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World_Cancer_Research_Fund.pdf (PDF, 12 Mo)
Physical Activity,
and the Prevention
of Cancer:
The most definitive review of the science to date,
and the most authoritative basis for action to
prevent cancer worldwide.
ecommendations based on expert
judgements of systematic reviews of the
world literature.
he result of a five-year examination by a
panel of the world's leading scientists.
u I ncludes new findings on early life, body
fatness, physical activity, and cancer
survivors.
ecommendations harmonised with
prevention of other diseases and promotion
of well-being.
vital guide for everybody, and the
indispensable text for policy-makers and
researchers.
Food, Nutrition, Physical Activity, and the
Prevention of Cancer: a Global Perspective
Food, Nutrition,
Research Fund
SECOND EXPERT REPORT
American Institute
for Cancer Research
World Cancer
Wereld Kanker
Onderzoek Fonds
www.aicr.org
www.wcrf-uk.org
www.wcrf-nl.org
ER HARD FINAL.indd 1
www.wcrf-hk.org
Fonds Mondial
www.fmrc.fr
P h y s i c a l A c t i v i t y, a n d t h e
P re v e n t i o n o f C a n c e r :
Please cite the Report as follows:
World Cancer Research Fund / American Institute for Cancer Research.
Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective.
Washington DC: AICR, 2007
First published 2007 by the American Institute for Cancer Research
1759 R St. NW, Washington, DC 20009
© 2007 World Cancer Research Fund International
Readers may make use of the text and graphic material in this Report
for teaching and personal purposes, provided they give credit to
World Cancer Research Fund and American Institute for Cancer Research.
CIP data in process
Printed in the United States of America by RR Donnelley
P re f a c e
I am very grateful to the special group of distinguished scientists who made up the Panel
and Secretariat for this major review of the evidence on food, nutrition, physical activity
and cancer. The vision of WCRF International in convening this Panel and confidence in
letting a strong-willed group of scientists have their way is to be highly commended.
In our view, the evidence reviewed here that led to our recommendations provides a
wonderful opportunity to prevent cancer and improve global health. Individuals and
populations have in their hands the means to lead fuller, healthier lives. Achieving that
will take action, globally, nationally, and locally, by communities, families, and
individuals.
It is worth pausing to put this Report in context. Public perception is often that experts
disagree. Why should the public or policy-makers heed advice if experts differ in their
views? Experts do disagree. That is the nature of science and a source of its strength.
Should we throw up our hands and say one opinion is as good as another? Of course not.
Evidence matters. But not evidence unguided by human thought. Hence the process that
was set up for this review: use a systematic approach to examine all the relevant evidence
using predetermined criteria, and assemble an international group of experts who, having
brought their own knowledge to bear and having debated their disagreements, arrive at
judgements as to what this evidence means. Both parts of the exercise were crucial: the
systematic review and, dare I say it, the wisdom of the experts.
The elegance of the process was one of the many attractions to me of assuming the role
of chair of the Panel. I could pretend that it was the major reason, and in a way it was, but
the first reason was enjoyment. What a pleasure and a privilege to spend three years in
the company of a remarkable group of scientists, including world leaders in research on
the epidemiology of cancer, as well as leaders in nutrition and public health and the
biology of cancer, to use a relatively new methodology (systematic literature reviews),
supported by a vigorous and highly effective Secretariat, on an issue of profound
importance to global public health: the prevention of cancer by means of healthy patterns
of eating and physical activity. It was quite as enjoyable as anticipated.
Given this heady mix, the reasons why I might have wanted to take on the role of Panel
chair were obvious. I did question the wisdom of WCRF International in inviting me to do
it. Much of my research has been on cardiovascular disease, not cancer. What I described
as my ignorance, WCRF International kindly labelled impartiality.
WCRF also appreciated the parallels between dietary causes of cardiovascular disease
and cancer. There is a great deal of concordance. In general, recommendations in this
Report to prevent cancer will also be of great relevance to cardiovascular disease. The only
significant contradiction is with alcohol. From the point of view of cancer prevention, the
best level of alcohol consumption is zero. This is not the case for cardiovascular disease,
where the evidence suggests that one to two drinks a day are protective. The Panel
therefore framed its recommendation to take this into account.
The fact that the conclusions and recommendations in this Report are the unanimous
view of the Panel does not imply that, miraculously, experts have stopped disagreeing. The
Panel debated the fine detail of every aspect of its conclusions and recommendations with
remarkable vigour and astonishing stamina. In my view, this was deliberation at its best. If
conclusions could simply fall out of systematic literature reviews, we would not have
needed experts to deliberate. Human judgement was vital; and if human, it cannot be
infallible. But I venture to suggest this process has led to as good an example of evidencebased public health recommendations as one can find.
Throughout the Panel's deliberations, it had in mind the global reach of this Report.
Most of the research on diet and cancer comes from high-income countries. But
noncommunicable diseases, including cancer, are now major public health burdens in
every region of the world. An important part of our deliberations was to ensure the
global applicability of our recommendations.
One last point about disagreement among experts: its relevance to the link between
science and policy. A caricature would be to describe science as precise and policy-makers
as indecisive. In a way, the opposite is the case. Science can say: could be, might be,
some of us think this, and some think that. Policy-makers have either to do it or not
do it — more often, not. Our effort here was to increase the precision of scientific
judgements. As the Report makes clear, many of our conclusions are in the 'could be'
category. None of our recommendations is based on these 'could be' conclusions. All are
based on judgements that evidence was definite or probable. Our recommendations, we
trust, will serve as guides to the population, to scientists, and to opinion-formers.
But what should policy-makers do with our judgements? A year after publication of
this Report, we will publish a second report on policy for diet, nutrition, physical activity,
and the prevention of cancer. As an exercise developing out of this one, we decided to
apply, as far as possible, the same principles of synthesis of evidence to policy-making.
We enhanced the scientific panel that was responsible for this Report with experts in
nutrition and food policy. This policy panel will oversee systematic literature reviews on
food policy, deliberate, and make recommendations.
The current Report and next year's Policy Report have one overriding aim: to reduce
the global burden of cancer by means of healthier living.
Michael Marmot
S u m m a ry
I n t ro d u c t i o n
■ PA RT O N E B A C K G R O U N D
Food systems and diets throughout history
Foods and drinks, physical activity,
Migrant and other ecological studies
T h e c a n c e r p ro c e s s
Basic concepts and principles
Cellular processes
Carcinogen metabolism
Judging the evidence
I n t e r n a t i o n a l v a r i a t i o n s a n d t re n d s
Epidemiological evidence
Experimental evidence
Methods of assessment
Causation and risk
Coming to judgement
■ PA RT T W O E V I D E N C E A N D J U D G E M E N T S
Cereals (grains), roots, tubers and plantains
Vegetables, fruits, pulses (legumes), nuts,
seeds, herbs, spices
4.3 Meat, poultry, fish and eggs
4.4 Milk, dairy products
4.5 Fats and oils
4.6 Sugars and salt
4.7 Water, fruit juices, soft drinks and hot drinks
4.8 Alcoholic drinks
4.9 Food production, processing, preservation
and preparation
4.10 Dietary constituents and supplements
4.11 Dietary patterns
G ro w t h , d e v e l o p m e n t , b o d y
Body fatness
Mouth, pharynx and larynx
Nasopharynx
Colon and rectum
Endometrium
D e t e rm i n a n t s o f w e i g h t g a i n ,
o v e rw e i g h t , o b e s i t y
C a n c e r s u rv i v o r s
C h a p t e r 1 0 F i n d i n g s o f o t h e r re p o r t s
Interpretation of the data
Chronic diseases other than cancer
C h a p t e r 1 1 R e s e a rc h i s s u e s
■ PA RT T H R E E R E C O M M E N D AT I O N S
Chapter 12 Public health goals and
p e r s o n a l re c o m m e n d a t i o n s
12.1 Principles
12.2 Goals and recommendations
12.3 Patterns of food, nutrition and
A p p e n d i x A P ro j e c t p ro c e s s
A p p e n d i x B T h e f i r s t W C R F / A I C R E x p e rt R e p o rt
Appendix C WCRF global network
G l o s s a ry
R e f e re n c e s
CHAPTER BOXES
Box 4.6.1
Measurement of food supply
and consumption
Measurement of cancer incidence
and mortality
Sugar, sugars, sugary foods and drinks
Salt and salty, salted and salt-preserved
Box 4.6.3 Chemical sweeteners
Box 4.6.4 Refrigeration
Box 4.7.1 High temperature, and irritant drinks
and foods
Box 4.7.2 Contamination of water, and of foods
and other drinks
Box 4.8.1 Types of alcoholic drink
Box 4.9.1 Food systems
Box 4.9.2 'Organic' farming
Box 4.9.3 Regulation of additives and
Box 4.9.4 Water fluoridation
Box 4.10.1 Food fortification
Box 4.10.2 Functional foods
Box 4.10.3 Levels of supplementation
Nutrition over the life course
Oncogenes and tumour suppressor genes
Mechanisms for DNA repair
Body fatness and attained height
Energy restriction
Energy cost and intensity of activity
Sedentary ways of life
G ro w t h , d e v e l o p m e n t , b o d y c o m p o s i t i o n
Sexual maturity
Age at menarche and risk of
Issues concerning interpretation of
Dose-response
Forest plots
Systematic literature reviews
Experimental findings
Effect modification
Energy adjustment
Criteria for grading evidence
Wholegrain and refined cereals and
their products
Foods containing dietary fibre
Glycaemic index and load
Micronutrients and other bioactive
compounds and cancer risk
Phytochemicals
Preparation of vegetables and nutrient
Processed meat
Nitrates, nitrites and N-nitroso
Foods containing iron
Heterocyclic amines and polycyclic
aromatic hydrocarbons
Cantonese-style salted fish
Foods containing calcium
Hydrogenation and trans-fatty acids
Box 7.13.1
Cancer incidence and survival
Hepatitis viruses
Human papilloma viruses
Energy density
Body fatness in childhood
Television viewing
Conventional and unconventional
Use of supplements by cancer survivors
F i n d i n g s o f o t h e r re p o r t s
R e s e a rc h i s s u e s
Box 12.1
Public health goals and personal
re c o m m e n d a t i o n s
Quantification
Making gradual changes
Height, weight and ranges of BMI
When supplements are advisable
Regional and special circumstances
F O O D , N U T R I T I O N , P H Y S I C A L A C T I V I T Y, A N D T H E P R E V E N T I O N O F C A N C E R : A G L O B A L P E R S P E C T I V E
Sir Michael Marmot
MB BS MPH PhD FRCP FFPH
Tola Atinmo PhD
University of Ibadan, Nigeria
Tim Byers MD MPH
University of Colorado Health
Sciences Center
Junshi Chen MD
Chinese Centre for Disease
Control and Prevention
Beijing, People's Republic of
Tomio Hirohata MD
DrScHyg PhD
Fukuoka City, Japan
Alan Jackson CBE MD FRCP
FRCPCH FRCPath
W Philip T James CBE MD
DSc FRSE FRCP
International Obesity Task
Laurence N Kolonel MD PhD
Jim Mann DM PhD FFPH
FRACP
Dunedin, New Zealand
Hilary J Powers PhD RNutr
University of Sheffield, UK
(WHO)
Denise Coitinho PhD
Ruth Bonita MD
Chizuru Nishida PhD MA
Pirjo Pietinen DSc
K Srinath Reddy MD DM MSc
Institute of Medical Sciences
Panel observers
members for policy
Elio Riboli MD ScM MPH
Was at: International Agency
for Research on Cancer
(IARC), Lyon, France
Now at: Imperial College
Organization of the United
Nations (FAO)
Guy Nantel PhD
Prakash Shetty MD PhD
Barry Popkin PhD MSc BSc
Carolina Population Center,
University of North Carolina,
Chapel Hill, NC, USA
Juan A Rivera PhD
Cuernavaca, Mexico
International Food Policy
Research Institute (IFPRI)
Washington DC, USA
Lawrence Haddad PhD
Marie Ruel PhD
Arthur Schatzkin MD DrPH
Rockville, MD, USA
International Union of
Nutritional Sciences (IUNS)
Mark Wahlqvist MD AO
Jacob C Seidell PhD
Free University Amsterdam
Mechanisms Working Group
John Milner PhD
David E G Shuker PhD FRSC
Methodology Task Force
Jos Kleijnen MD PhD
Gillian Reeves PhD
Ricardo Uauy MD PhD
Instituto de Nutricion y
Tecnologia de los Alimentos
Union Internationale Contre
le Cancer (UICC)
Annie Anderson PhD
Curtis Mettlin PhD
Harald zur Hausen MD DSc
Shiriki Kumanyika PhD MPH
Walter C Willett MD DrPH
Harvard School of Public
Claus Leitzmann PhD
Justus Liebig University
Giessen, Germany
Steven H Zeisel MD PhD
Robert Beaglehole ONZM
FRSNZ DSc
Was at: World Health
Organization (WHO)
Now at: University of
United Nations Children's
Fund (UNICEF)
Ian Darnton-Hill MD MPH
Rainer Gross Dr Agr
Jane Wardle PhD MPhil
University College London, UK
Nick Cavill MPH
University of Oxford, UK
A C K N O W L E D G E M E N T S
University of Bristol, UK
Rajendra Persad ChM FEBU
FRCS
United Bristol Healthcare
Trust & Bristol Urological
Institute, UK
Carlos A Gonzalez PhD MPH
Catalan Institute of Oncology
Vittorio Krogh MD MSc
Istituto Nazionale Tumori
George Davey Smith
FMedSci FRCP DSc
University of Bristol , UK
Massimo Pignatelli MD PhD
FRCPath
Jonathan Sterne PhD MSc
Jelena Savovic PhD
Sylvie Menard ScD
Steve Thomas MB BS PhD
Eugenio Mugno ScD
Tim Whittlestone MA MD
Trust, UK
Valeria Pala ScD
Chris Bain MB BS MS MPH
Nahida Banu MB BS
Trudy Bekkering PhD
Luisa Zuccolo MSc
Sabina Sieri ScD
Rebecca Beynon MA BSc
Margaret Burke MSc
David de Berker MB BS MRCP
Anna A Davies MSc BSc
Roger Harbord MSc
Ross Harris MSc
Lee Hooper PhD SRD
Anne-Marie Mayer PhD MSc
Andy Ness PhD FFPHM MRCP
Tu m o r i M i l a n , I t a l y
Franco Berrino MD
Patrizia Pasanisi MD MSc
Claudia Agnoli ScD
Silvana Canevari ScD
Giovanni Casazza ScD
Elisabetta Fusconi ScD
U n i v e r s i t y, B a l t i m o re ,
Anthony J Alberg PhD MPH
Columbia, SC, USA
Kristina Boyd MS
Laura Caulfield PhD
Eliseo Guallar MD DrPH
James Herman MD
Karen Robinson MSc
Xuguang (Grant) Tao MD
University of Leeds, UK
David Forman PhD FFPH
Victoria J Burley PhD MSc
RPHNutr
Janet E Cade PhD BSc
Darren C Greenwood MSc
Doris S M Chan MSc
Jennifer A Moreton PhD MSc
James D Thomas
Yu-Kang Tu PhD MSc DDS
Iris Gordon MSc
Kenneth E L McColl FRSE
FMedSci FRCP
Western Infirmary
Lisa Dyson MSc
Genevieve Matanoski MD
DrPH
London School of
H y g i e n e & Tr o p i c a l
Medicine, UK
P e n n S t a t e U n i v e r s i t y,
University Park,
PA , U S A
Alan D Dangour PhD MSc
London School of Hygiene &
Tropical Medicine, UK
Terryl J Hartman PhD MPH
Penn State University,
University Park, PA, USA
Shefalee Mehta MSc
Abigail Perry MSc
Sakhi Kiran Dodhia MSc
Vicki Pyne MSc
U n i v e r s i t y o f Te e s s i d e ,
Carolyn Summerbell PhD
University of Teesside
Middlesbrough, UK
Sarah Kelly PhD
Louisa Ells PhD
Frances Hillier MSc
Sarah Smith MSc
Alan Batterham PhD
Laurel Edmunds PhD
Vicki Whittaker MSc
Ian Macdonald PhD
David Mauger PhD
Penn State College of
Lindsay Camera MS
M Jenny Harris Ledikwe PhD
Linda Kronheim MS
Keith R Martin PhD MTox
Tara Murray
Michele L Shaffer PhD
Dina M Gifkins MPH
The Cancer Institute of New
Marjorie L McCullough RD
Wa g e n i n g e n U n i v e r s i t y,
Pieter van 't Veer PhD
Ellen Kampman PhD
Marije Schouten PhD
Bianca Stam MSc
Claudia Kamphuis MSc
Maureen van den Donk PhD
Marian Bos MSc
Anouk Geelen PhD
Evelien Smit MSc
Salome Scholtens MSc
Evert-Jan Bakker PhD
Jan Burema MSc
Marianne Renkema PhD
Henk van Kranen PhD
National Institute for Health
and the Environment (RIVM)
Bilthoven, the Netherlands
Narrative review
Liju Fan PhD
Ontology Workshop
Luigino Dal Maso ScD
Aviano Cancer Center
Michael Garner MSc
Kim Spaccarotella PhD
Rutgers, The State University
of New Jersey, New
Brunswick, NJ, USA
Akke Botma MSc
K a i s e r P e rm a n e n t e ,
Oakland, California, USA
Simone Croezen MSc
Frank M Torti MD MPH
Wake Forest University,
Comprehensive Cancer Unit
Winston-Salem, NC, USA
Mirjam Meltzer MSc
Christine F Skibola PhD
University of California,
Berkeley, CA, USA
Elisa V Bandera MD PhD
Lawrence H Kushi ScD
Dirk F Moore PhD
Fleur Schouten MSc
Janneke Ploemacher MSc
Khahn Le MSc
Martin Wiseman FRCP
WCRF International
Sheila A Bingham PhD
FMedSci
MRC Dunn Human Nutrition
Cambridge, UK
Heiner Boeing PhD
German Institution of Human
Eric Brunner PhD FFPH
University College London,
H Bas Bueno de Mesquita MD
MPH PhD
National Institute of Public
Health and the Environment
(RIVM)
Ian Frayling PhD MRCPath
Addenbrookes Hospital
Andreas J Gescher DSc
University of Leicester, UK
Tim Key PhD
Epidemiology Unit,
Oxford, UK
Was at: University of York, UK
Now at: Kleijnen Systematic
Reviews, York, UK
Barrie Margetts MSc PhD
MFPH
University of Southampton,
Robert Owen PhD
German Cancer Research
David E G Shuker PhD
Peer reviewers and
David S Alberts MD
Arizona Cancer Center
Nahida Banu MBBS
Chris Bain MBBS MPH
Xavier Castellsagué Pique
PhD MD MPH
Amy Berrington de Gonzalez
DPhil MSc
Sanford M Dawsey MD
Michael Sjöström MD PhD
Karolinska Institute
Chris Williams MD
Cochrane Cancer Network
Stephen Hursting PhD
Henry Kitchener MD
MRCPath
Diane Birt PhD
Ames, IA, USA
Steven Blair PED
Judith Bliss MSc
The Institute of Cancer
Sutton, UK
Cristina Bosetti ScD
Istituto di Recherche
Farmacologiche "Mario
Paul Brennan PhD MSc
International Agency for
Research on Cancer (IARC)
Johannes Brug PhD FFPH
Institute for Research in
Extramural Medicine
(EMGO),
VU University Medical Centre
Noel Cameron BEd MSc
Loughborough University, UK
Moira Chan-Yeung MBBS
FRCP FACP
Robert Clarke DSc PhD
Lombardi Comprehensive
Cancer Center, Georgetown
Steven K Clinton MD PhD
Columbus, OH, USA
Karen Collins MS RD
Nutrition Advisor
AICR
Elizabeth TH Fontham DrPH
Louisiana State University of
Terrence Forrester MB BS DM
FRCP
Teresa Fung ScD RD MSc
Simmons College and
John Garrow MD PhD FRCP
University of London, UK
Glenn Gibson PhD
University of Reading, UK
Brian Cox MBChB PhD
FAFPHM
Ian Gilmore MD PRCP
Cindy Davis PhD
Vay Liang W Go MD
Diana Dyer MS RD
Ann Arbor, MI, USA
Per Hall MD PhD
Jonathan Earle MB BCh FCAP
Alison Eastwood MSc
Ibrahim Elmadfa PhD
Dallas English PhD MSc
Michael Fenech PhD MSc BSc
Commonwealth Scientific and
Organization (CSIRO)
Justin Fenty MSc
Lynn Ferguson DSc DPhil MSc
Univerity of Auckland
Laura Hardie PhD
Peter Herbison MSc
Victor Kipnis PhD
Paul Knekt PhD
National Public Health
Thilo Kober PhD
Cochrane Haematological
Malignancies Group
Suminori Kono PhD MD MSc
Nancy Kreiger PhD MPH
Cancer Care Ontario and
Petra Lahmann PhD
Fabio Levi MD MSc
Institut Universitaire de
Médecine Sociale et
Ruth Lewis MSc
Cardiff University, UK
Albert B Lowenfels MD
Melvyn Hillsdon PhD
Graham A MacGregor FRCP
St George's University of
Edward Hurwitz DC PhD
Geoffrey Marks PhD MS
Susan Jebb PhD
MRC Human Nutrition
John Mathers PhD DipNutr
University of Newcastle, UK
Stanley B Kaye MD FRCP
Sam McClinton MD FRCS
NHS Grampian
Tony McMichael MB BS PhD
The Australian National
Dominique Michaud ScD
Anthony B Miller MD FRCP
Sidney Mirvish PhD
Max Parkin MD
Charlotte Paul MB ChB PhD
John Reilly PhD
University of Glasgow, UK
Richard Rivlin MD
Strang Cancer Research
Andrew Roddam DPhil
Epidemiology Unit
Leo Schouten MD PhD
Nutrition and Toxicology
Research Institute Maastricht
Jackilen Shannon PhD MPH
Oregon Health and Science
Portland, OR, USA
Fiona Mensah
Keith Singletary PhD
Urbana, IL, USA
Margaret McCredie PhD
Rashmi Sinha PhD
Rachael Stolzenberg-Solomon
PhD MPH RD
Boyd Swinburn MB ChB MD
Peter Szlosarek MRCP PhD
St Bartholomew's Hospital
Paul Talalay MD
Margaret Thorogood PhD
University of Warwick, UK
Stewart Truswell MD DSc
Paolo Vineis MD MPH
Steven Waggoner MD
Case Comprehensive Cancer
Cleveland, OH, USA
Christopher P Wild PhD
Anthony Williams DPhil FRCP
FRCPCH
Frederic M Wolf PhD MEd
Jian-Min Yuan MD PhD
University of Minnesota,
Minneappolis, MN, USA
Maurice Zeegers PhD MSc
WCRF/AICR Report
Marilyn Gentry
WCRF Global Network
Kelly Browning
Kate Allen PhD
Kathryn L Ward
Senior Vice-President
Deirdre McGinley-Gieser
Kate Coughlin BSc
Science Programme Manager
Cara James
Associate Director for
Jennifer Kirkwood
Anja Kroke MD PhD MPH
Fulda, Germany
Jeffrey R Prince PhD
Vice-President for Education
and Communications
Kayte Lawton
Lisa Miles MSc
Geoffrey Cannon
Ritva R Butrum PhD
Senior Science Advisor
Greg Martin MB BCh MPH
Susan Higginbotham PhD
Director for Research
Steven Heggie PhD
Alison Bailey
Redhill, UK
Poling Chow BSc
Sarah Nalty MSc
Edmund Peston
Ivana Vucenik PhD
Joan Ward
Julia Wilson PhD
Art & production
Design and Art Director
Design4Science Ltd
Emma Copeland PhD
Rosalind Holmes
Fletcher Ward Design
Ann O'Malley
Print Manager
Geoff Simmons
Design & Production Manager
WCRF UK
Serena Prince
Melissa Samaroo
Elaine Stone PhD
Rachel Thompson PhD
Review Coordinator
This summary provides an abbreviated version of the full
Report. It highlights the wealth of information and data
studied by the Panel and is designed to give readers an
overview of the key issues contained within the Report,
notably the process, the synthesis of the scientific evidence,
and the resulting judgements and recommendations.
T h e f i r s t a n d s e c o n d R e p o rt s
Food, Nutrition and the Prevention of Cancer: a global perspective, produced by the World Cancer Research Fund
together with the American Institute for Cancer Research,
has been the most authoritative source on food, nutrition,
and cancer prevention for 10 years. On publication in 1997,
it immediately became recognised as the most authoritative
and influential report in its field and helped to highlight the
importance of research in this crucial area. It became the
standard text worldwide for policy-makers in government
at all levels, for civil society and health professional organisations, and in teaching and research centres of academic
excellence.
Since the mid-1990s the amount of scientific literature on
this subject has dramatically increased. New methods of
analysing and assessing evidence have been developed,
facilitated by advances in electronic technology. There is
more evidence, in particular on overweight and obesity and
on physical activity; food, nutrition, physical activity, and
cancer survivors is a new field. The need for a new report
was obvious; and in 2001 WCRF International in collaboration with AICR began to put in place a global process in
order to produce and publish the Report in November 2007.
H o w t h i s R e p o rt h a s b e e n a c h i e v e d
The goal of this Report is to review all the relevant research,
using the most meticulous methods, in order to generate a
comprehensive series of recommendations on food, nutrition, and physical activity, designed to reduce the risk of
cancer and suitable for all societies. This process is also the
basis for a continuous review of the evidence.
Organised into overlapping stages, the process has been
designed to maximise objectivity and transparency, separating the collection of evidence from its assessment and
judgement. First, an expert task force developed a method
for systematic review of the voluminous scientific literature.
Second, research teams collected and reviewed the literature based upon this methodology. Third, an expert Panel
has assessed and judged this evidence and agreed recommendations. The results are published in this Report and
summarised here. A more detailed explanation of this
process is given in Chapter 3 and the research teams and
investigators involved are listed on pages viii–xi.
This Report is a guide to future scientific research, cancer
prevention education programmes, and health policy
around the world. It provides a solid evidence base for
policy-makers, health professionals, and informed and
interested people to draw on and work with.
Overview of the second expert Report
This Report has a number of inter-related general purposes.
One is to explore the extent to which food, nutrition, physical activity, and body composition modify the risk of cancer, and to specify which factors are most important. To the
extent that environmental factors such as food, nutrition,
and physical activity influence the risk of cancer, it is a preventable disease. The Report specifies recommendations
based on solid evidence which, when followed, will be
expected to reduce the incidence of cancer.
P a r t 1 — B a c k g ro u n d
Chapter 1 shows that patterns of production and consumption of food and drink, of physical activity, and of body
composition have changed greatly throughout human
history. Remarkable changes have taken place as a result
of urbanisation and industrialisation, at first in Europe,
North America, and other economically advanced countries, and increasingly in most countries in the world.
Notable variations have been identified in patterns of cancer throughout the world. Significantly, studies consistently
show that patterns of cancer change as populations migrate
from one part of the world to another and as countries
become increasingly urbanised and industrialised. Projections indicate that rates of cancer in general are liable
to increase.
Chapter 2 outlines current understanding of the biology
of the cancer process, with special attention to the ways in
which food and nutrition, physical activity, and body composition may modify the risk of cancer. Cancer is a disease
of genes, which are vulnerable to mutation, especially over
the long human lifespan. However, evidence shows that
only a small proportion of cancers are inherited.
Environmental factors are most important and can be modified. These include smoking and other use of tobacco;
infectious agents; radiation; industrial chemicals and pollution; medication; and also many aspects of food, nutrition,
physical activity, and body composition.
S U M M A R Y
Chapter 3 summarises the types of evidence that the
Panel has agreed are relevant to its work. No single study
or study type can prove that any factor definitely is a cause
of, or is protective against, any disease. In this chapter,
building on the work of the first report, the Panel shows
that reliable judgements on causation of disease are based
on assessment of a variety of well-designed epidemiological and experimental studies.
The prevention of cancer worldwide is one of the most
pressing challenges facing scientists and public health
policy-makers, among others. These introductory chapters
show that the challenge can be effectively addressed and
suggest that food, nutrition, physical activity, and body
composition play a central part in the prevention of cancer.
P a rt 2 — E v i d e n c e a n d J u d g e m e n t s
The judgements made by the Panel in Part 2 are based on
independently conducted systematic reviews of the literature commissioned from academic institutions in the USA,
UK, and continental Europe. The evidence has been meticulously assembled and, crucially, the display of the evidence was separated from assessments derived from that
evidence. Seven chapters present the findings of these
reviews. The Panel's judgements are displayed in the form
of matrices that introduce five of these chapters, and in the
summary matrix on the fold-out page inside the back cover.
Chapter 4, the first and longest chapter in Part 2, is concerned with types of food and drink. The judgements of the
Panel are, whenever possible, food- and drink-based,
reflecting the most impressive evidence. Findings on
dietary constituents and micronutrients (for example foods
containing dietary fibre) are identified where appropriate.
Evidence on dietary supplements, and on patterns of diet,
is included in the two final sections of this chapter.
Chapters 5 and 6 are concerned with physical activity
and with body composition, growth, and development.
Evidence in these areas is more impressive than was the
case up to the mid-1990s; the evidence on growth and
development indicates the importance of an approach to
the prevention of cancer that includes the whole life
Chapter 7 summarises and judges the evidence as
applied to 17 cancer sites, with additional briefer summaries based on narrative reviews of five further body systems and cancer sites. The judgements shown in the
matrices in this chapter correspond with the judgements
shown in the matrices in the previous chapters.
Obesity is or may be a cause of a number of cancers.
Chapter 8 identifies what aspects of food, nutrition, and
physical activity themselves affect the risk of obesity and
associated factors. The judgements, which concern the biological and associated determinants of weight gain, overweight, and obesity, are based on a further systematic
literature review, amplified by knowledge of physiological
processes.
The relevance of food, nutrition, physical activity, and
body composition to people living with cancer, and to the
prevention of recurrent cancer, is summarised in Chapter 9.
Improved cancer screening, diagnosis, and medical services
are, in many countries, improving survival rates. So the
number of cancer survivors — people living after diagnosis
of cancer — is increasing.
The Panel agreed that its recommendations should also
take into account findings on the prevention of other chronic diseases, and of nutritional deficiencies and nutritionrelated infectious diseases, especially of childhood. Chapter
10, also based on a systematic literature review, is a summary of the findings of expert reports in these areas.
The research issues identified in Chapter 11 are, in the
view of the Panel, the most promising avenues to explore in
order to refine understanding of the links between food,
nutrition, physical activity, and cancer, and so improve the
prevention of cancer, worldwide.
P a rt 3 — R e c o m m e n d a t i o n s
Chapter 12, the culmination of the five-year process, presents the Panel's public health goals and personal recommendations. These are preceded by a statement of the
principles that have guided the Panel in its thinking.
The goals and recommendations are based on 'convincing' or 'probable' judgements made by the Panel in the chapters in Part 2. These are proposed as the basis for public
policies and for personal choices that, if effectively implemented, will be expected to reduce the incidence of cancer
for people, families, and communities.
Eight general and two special goals and recommendations are detailed. In each case a general recommendation
is followed by public health goals and/or personal recommendations, together with further explanation or clarification as required. Chapter 12 also includes a summary of the
evidence, justification of the goals and recommendations,
and guidance on how to achieve them.
The process of moving from evidence to judgements and
to recommendations has been one of the Panel's main
responsibilities, and has involved discussion and debate
until final agreement has been reached. The goals and recommendations here have been unanimously agreed.
The goals and recommendations are followed by the
Panel's conclusions on the dietary patterns most likely to
protect against cancer. In order to discern the 'big picture' of
healthy and protective diets, it is necessary to integrate a
vast amount of detailed information. The Panel used a
broad, integrative approach that, while largely derived from
conventional 'reductionist' research, has sought to find patterns of food and drink consumption, of physical activity,
and of body fatness, that enable recommendations designed
to prevent cancer at personal and population levels.
The goals and recommendations are designed to be generally relevant worldwide and the Panel recognises that in
national settings, the recommendations of this Report will
be best used in combination with recommendations, issued
by governments or on behalf of nations, designed to prevent
chronic and other diseases. In addition, the Panel cited
three specific cases where the evidence is strong enough to
be the basis for goals and recommendations, but which currently are relevant only in discrete geographical regions:
maté in Latin America, Cantonese-style salted fish in the
Pearl River Delta in Southern China, and arsenic contaminating water supplies in several locations. Further details on
nutritional patterns and regional and special circumstances
can be found in section 12.3.
The main focus of this Report is on nutritional and other
biological and associated factors that modify the risk of cancer. The Panel is aware that as with other diseases, the risk
of cancer is also modified by social, cultural, economic, and
ecological factors. Thus the foods and drinks that people
consume are not purely because of personal choice; likewise
opportunities for physical activity can be constrained.
Identifying the deeper factors that affect cancer risk enables
a wider range of policy recommendations and options to be
identified. This is the subject of a separate report to be published in late 2008.
The public health goals and personal recommendations of
the Panel that follow are offered as a significant contribution towards the prevention and control of cancer throughout the world.
The Panel's recommendations
The Panel's goals and recommendations that follow are
guided by several principles, the details of which can be
found in Chapter 12. The public health goals are for
populations, and therefore for health professionals; the
recommendations are for people, as communities, families,
and individuals.
The Panel also emphasises the importance of not smoking
and avoiding exposure to tobacco smoke.
The goals and recommendations begin with a general statement. This is followed by the population goal and the personal recommendation, together with any necessary
footnotes. These footnotes are an integral part of the
recommendations. The full recommendations, including
further clarification and qualification, can be found in
RECOMMENDATION 1
B O D Y FAT N E S S
Be as lean as possible within
t h e n o rm a l r a n g e1 o f b o d y w e i g h t
B e p h y s i c a l l y a c t i v e a s p a rt o f e v e ry d a y l i f e
PUBLIC HEALTH GOALS
The proportion of the population that is sedentary1
to be halved every 10 years
Median adult body mass index (BMI) to be
between 21 and 23, depending on the
normal range for different populations2
Average physical activity levels (PALs)1 to be above 1.6
The proportion of the population that is overweight
or obese to be no more than the current level,
or preferably lower, in 10 years
PERSONAL RECOMMENDATIONS
Be moderately physically active, equivalent
to brisk walking,2 for at least 30 minutes every day
As fitness improves, aim for 60 minutes or more
of moderate, or for 30 minutes or more of
vigorous, physical activity every day2 3
Ensure that body weight through
childhood and adolescent growth projects3 towards the
lower end of the normal BMI range at age 21
Limit sedentary habits such as watching television
Maintain body weight within
the normal range from age 21
Avoid weight gain and increases in
waist circumference throughout adulthood
'Normal range' refers to appropriate ranges issued by national governments or
the World Health Organization
To minimise the proportion of the population outside the normal range
'Projects' in this context means following a pattern of growth (weight and
height) throughout childhood that leads to adult BMI at the lower end of the
normal range. Such patterns of growth are specified in International Obesity
Task Force and WHO growth reference charts
Maintenance of a healthy weight throughout life may be
one of the most important ways to protect against cancer.
This will also protect against a number of other common
chronic diseases.
Weight gain, overweight, and obesity are now generally
much more common than in the 1980s and 1990s. Rates of
overweight and obesity doubled in many high-income countries between 1990 and 2005. In most countries in Asia and
Latin America, and some in Africa, chronic diseases including obesity are now more prevalent than nutritional deficiencies and infectious diseases.
Being overweight or obese increases the risk of some cancers. Overweight and obesity also increase the risk of conditions including dyslipidaemia, hypertension and stroke, type
2 diabetes, and coronary heart disease. Overweight in childhood and early life is liable to be followed by overweight
and obesity in adulthood. Further details of evidence and
judgements can be found in Chapters 6 and 8. Maintenance
of a healthy weight throughout life may be one of the most
important ways to protect against cancer.
The term 'sedentary' refers to a PAL of 1.4 or less. PAL is a way of representing
the average intensity of daily physical activity. PAL is calculated as total energy
expenditure as a multiple of basal metabolic rate
Can be incorporated in occupational, transport, household, or leisure activities
This is because physical activity of longer duration or greater intensity is more
Most populations, and people living in industrialised and
urban settings, have habitual levels of activity below levels
to which humans are adapted.
With industrialisation, urbanisation, and mechanisation,
populations and people become more sedentary. As with
overweight and obesity, sedentary ways of life have been
usual in high-income countries since the second half of the
20th century. They are now common if not usual in most
All forms of physical activity protect against some cancers, as well as against weight gain, overweight, and obesity; correspondingly, sedentary ways of life are a cause of
these cancers and of weight gain, overweight, and obesity.
Weight gain, overweight, and obesity are also causes of
some cancers independently of the level of physical activity.
Further details of evidence and judgements can be found in
Chapters 5, 6, and 8.
The evidence summarised in Chapter 10 also shows that
physical activity protects against other diseases and that
sedentary ways of life are causes of these diseases.
F O O D S A N D D R I N K S T H AT
PROMOTE WEIGHT GAIN
PLANT FOODS
Eat mostly foods of plant origin
L i m i t c o n s u m p t i o n o f e n e rg y - d e n s e f o o d s1
Av o i d s u g a r y d r i n k s 2
Population average consumption of non-starchy1
vegetables and of fruits to be at least 600 g (21 oz) daily2
Average energy density of diets3 to be lowered
towards 125 kcal per 100 g
Relatively unprocessed cereals (grains) and/or pulses
(legumes), and other foods that are a natural source of
dietary fibre, to contribute to a population average
of at least 25 g non-starch polysaccharide daily
Population average consumption of sugary drinks2
Eat at least five portions/servings
(at least 400 g or 14 oz) of a variety2 of
non-starchy vegetables and of fruits every day
Consume energy-dense foods1 4 sparingly
Avoid sugary drinks2
Eat relatively unprocessed cereals (grains)
and/or pulses (legumes) with every meal3
Consume 'fast foods'5 sparingly, if at all
Energy-dense foods are here defined as those with an energy content of more
than about 225–275 kcal per 100 g
This principally refers to drinks with added sugars. Fruit juices should also be
This does not include drinks
Limit processed energy-dense foods (also see recommendation 4). Relatively
unprocessed energy-dense foods, such as nuts and seeds, have not been shown
to contribute to weight gain when consumed as part of typical diets, and these
and many vegetable oils are valuable sources of nutrients
The term 'fast foods' refers to readily available convenience foods that tend to
be energy-dense and consumed frequently and in large portions
Consumption of energy-dense foods and sugary drinks is
increasing worldwide and is probably contributing to the
global increase in obesity.
This overall recommendation is mainly designed to prevent
and to control weight gain, overweight, and obesity.
'Energy density' measures the amount of energy (in kcal
or kJ) per weight (usually 100 g) of food. Food supplies that
are mainly made up of processed foods, which often contain
substantial amounts of fat or sugar, tend to be more energydense than food supplies that include substantial amounts
of fresh foods. Taken together, the evidence shows that it is
not specific dietary constituents that are problematic, so
much as the contribution these make to the energy density
of diets.
Because of their water content, drinks are less energydense than foods. However, sugary drinks provide energy
but do not seem to induce satiety or compensatory reduction in subsequent energy intake, and so promote overconsumption of energy and thus weight gain.
Limit refined starchy foods
People who consume starchy roots or tubers4
as staples also to ensure intake of sufficient
non-starchy vegetables, fruits, and pulses (legumes)
This is best made up from a range of various amounts of non-starchy vegetables
and fruits of different colours including red, green, yellow, white, purple, and
orange, including tomato-based products and allium vegetables such as garlic
Relatively unprocessed cereals (grains) and/or pulses (legumes) to contribute
to an average of at least 25 g non-starch polysaccharide daily
These foods are low in energy density and so promote healthy weight
For example, populations in Africa, Latin America, and the Asia-Pacific region
An integrated approach to the evidence shows that most
diets that are protective against cancer are mainly made up
from foods of plant origin.
Higher consumption of several plant foods probably protects
against cancers of various sites. What is meant by 'plantbased' is diets that give more emphasis to those plant foods
that are high in nutrients, high in dietary fibre (and so in nonstarch polysaccharides), and low in energy density. Nonstarchy vegetables, and fruits, probably protect against some
cancers. Being typically low in energy density, they probably
also protect against weight gain. Further details of evidence
and judgements can be found in Chapters 4 and 8.
Non-starchy vegetables include green, leafy vegetables,
broccoli, okra, aubergine (eggplant), and bok choy, but not,
for instance, potato, yam, sweet potato, or cassava. Nonstarchy roots and tubers include carrots, Jerusalem artichokes, celeriac (celery root), swede (rutabaga), and turnips.
ANIMAL FOODS
m e a t1
L i m i t i n t a k e o f re d
a v o i d p ro c e s s e d m e a t 2
L i m i t a l c o h o l i c d r i n k s1
PUBLIC HEALTH GOAL
Proportion of the population drinking
more than the recommended limits to be
reduced by one third every 10 years1 2
Population average consumption of red meat
to be no more than 300 g (11 oz) a week,
very little if any of which to be processed
PERSONAL RECOMMENDATION
If alcoholic drinks are consumed,
limit consumption to no more than two drinks a day
for men and one drink a day for women1 2 3
People who eat red meat1
to consume less than 500 g (18 oz) a week,
very little if any to be processed2
'Red meat' refers to beef, pork, lamb, and goat from domesticated animals
including that contained in processed foods
'Processed meat' refers to meat preserved by smoking, curing or salting, or
addition of chemical preservatives, including that contained in processed foods
An integrated approach to the evidence also shows that
many foods of animal origin are nourishing and healthy if
consumed in modest amounts.
People who eat various forms of vegetarian diets are at low
risk of some diseases including some cancers, although it is
not easy to separate out these benefits of the diets from
other aspects of their ways of life, such as not smoking,
drinking little if any alcohol, and so forth. In addition, meat
can be a valuable source of nutrients, in particular protein,
iron, zinc, and vitamin B12. The Panel emphasises that this
overall recommendation is not for diets containing no meat
— or diets containing no foods of animal origin. The
amounts are for weight of meat as eaten. As a rough conversion, 300 g of cooked red meat is equivalent to about
400–450 g raw weight, and 500 g cooked red meat to about
700–750 g raw weight. The exact conversion will depend
on the cut of meat, the proportions of lean and fat, and the
method and degree of cooking, so more specific guidance is
not possible. Red or processed meats are convincing or
probable causes of some cancers. Diets with high levels of
animal fats are often relatively high in energy, increasing
the risk of weight gain. Further details of evidence and
judgements can be found in Chapters 4 and 8.
Recommendation 4, continued from page xviii
The goals and recommendations here are broadly similar
to those that have been issued by other international and
national authoritative organisations (see Chapter 10). They
derive from the evidence on cancer and are supported by
evidence on other diseases. They emphasise the importance
This recommendation takes into account that there is a likely protective effect
for coronary heart disease
Children and pregnant women not to consume alcoholic drinks
One 'drink' contains about 10–15 grams of ethanol
The evidence on cancer justifies a recommendation not to
drink alcoholic drinks. Other evidence shows that modest
amounts of alcoholic drinks are likely to reduce the risk of
coronary heart disease.
The evidence does not show a clear level of consumption of
alcoholic drinks below which there is no increase in risk of
the cancers it causes. This means that, based solely on the
evidence on cancer, even small amounts of alcoholic drinks
should be avoided. Further details of evidence and judgements can be found in Chapter 4. In framing the recommendation here, the Panel has also taken into account the
evidence that modest amounts of alcoholic drinks are likely
to protect against coronary heart disease, as described in
The evidence shows that all alcoholic drinks have the
same effect. Data do not suggest any significant difference
depending on the type of drink. This recommendation
therefore covers all alcoholic drinks, whether beers, wines,
spirits (liquors), or other alcoholic drinks. The important
factor is the amount of ethanol consumed.
The Panel emphasises that children and pregnant women
should not consume alcoholic drinks.
of relatively unprocessed cereals (grains), non-starchy vegetables and fruits, and pulses (legumes), all of which contain
substantial amounts of dietary fibre and a variety of
micronutrients, and are low or relatively low in energy density. These, and not foods of animal origin, are the recommended centre for everyday meals.
P R E S E R VAT I O N , P R O C E S S I N G ,
P R E PA R ATION
D I E TA R Y S U P P L E M E N T S
Aim to meet nutritional needs
t h ro u g h d i e t a l o n e 1
s a l t1
Limit consumption of
A v o i d m o u l d y c e re a l s ( g r a i n s ) o r p u l s e s ( l e g u m e s )
Maximise the proportion of the population achieving
nutritional adequacy without dietary supplements
Population average consumption of salt from
all sources to be less than 5 g (2 g of sodium) a day
Proportion of the population consuming more than 6 g
of salt (2.4 g of sodium) a day to be halved every 10 years
Minimise exposure to aflatoxins
from mouldy cereals (grains) or pulses (legumes)
Dietary supplements are not recommended
for cancer prevention
This may not always be feasible. In some situations of illness or dietary
inadequacy, supplements may be valuable
Avoid salt-preserved, salted, or salty foods;
preserve foods without using salt1
Limit consumption of processed foods with added salt
to ensure an intake of less than 6 g (2.4 g sodium) a day
Do not eat mouldy cereals (grains) or pulses (legumes)
Methods of preservation that do not or need not use salt include refrigeration,
freezing, drying, bottling, canning, and fermentation
The strongest evidence on methods of food preservation, processing, and preparation shows that salt and salt-preserved
foods are probably a cause of stomach cancer, and that foods
contaminated with aflatoxins are a cause of liver cancer.
Salt is necessary for human health and life itself, but at levels very much lower than those typically consumed in most
parts of the world. At the levels found not only in highincome countries but also in those where traditional diets
are high in salt, consumption of salty foods, salted foods,
and salt itself is too high. The critical factor is the overall
amount of salt. Microbial contamination of foods and drinks
and of water supplies remains a major public health problem worldwide. Specifically, the contamination of cereals
(grains) and pulses (legumes) with aflatoxins, produced by
some moulds when such foods are stored for too long in
warm temperatures, is an important public health problem,
and not only in tropical countries.
Salt and salt-preserved foods are a probable cause of
some cancers. Aflatoxins are a convincing cause of liver cancer. Further details of evidence and judgements can be
found in Chapter 4.
The evidence shows that high-dose nutrient supplements
can be protective or can cause cancer. The studies that
demonstrate such effects do not relate to widespread use
among the general population, in whom the balance of
risks and benefits cannot confidently be predicted. A general recommendation to consume supplements for cancer
prevention might have unexpected adverse effects.
Increasing the consumption of the relevant nutrients
through the usual diet is preferred.
The recommendations of this Report, in common with its
general approach, are food based. Vitamins, minerals, and
other nutrients are assessed in the context of the foods and
drinks that contain them. The Panel judges that the best
source of nourishment is foods and drinks, not dietary supplements. There is evidence that high-dose dietary supplements can modify the risk of some cancers. Although some
studies in specific, usually high-risk, groups have shown evidence of cancer prevention from some supplements, this
finding may not apply to the general population. Their level
of benefit may be different, and there may be unexpected
and uncommon adverse effects. Therefore it is unwise to
recommend widespread supplement use as a means of cancer prevention. Further details of evidence and judgements
can be found in Chapter 4.
In general, for otherwise healthy people, inadequacy of
intake of nutrients is best resolved by nutrient-dense diets
and not by supplements, as these do not increase consumption of other potentially beneficial food constituents. The
Panel recognises that there are situations when supplements
are advisable. See box 12.4.
SPECIAL RECOMMENDATION 1
C A N C E R S U R V I V O R S1
M o t h e r s t o b re a s t f e e d ; c h i l d re n t o b e b re a s t f e d 1
F o l l o w t h e re c o m m e n d a t i o n s
f o r c a n c e r p re v e n t i o n 2
The majority of mothers to breastfeed
exclusively, for six months2 3
All cancer survivors3 to receive nutritional care
from an appropriately trained professional
If able to do so, and unless otherwise advised,
aim to follow the recommendations for
diet, healthy weight, and physical activity2
Aim to breastfeed infants exclusively2
up to six months and continue
with complementary feeding thereafter3
Breastfeeding protects both mother and child
'Exclusively' means human milk only, with no other food or drink, including
In accordance with the UN Global Strategy on Infant and Young Child Feeding
The evidence on cancer as well as other diseases shows
that sustained, exclusive breastfeeding is protective for the
mother as well as the child.
This is the first major report concerned with the prevention
of cancer to make a recommendation specifically on breastfeeding, to prevent breast cancer in mothers and to prevent
overweight and obesity in children. Further details of evidence and judgements can be found in Chapters 6 and 8.
Other benefits of breastfeeding for mothers and their
children are well known. Breastfeeding protects against
infections in infancy, protects the development of the
immature immune system, protects against other childhood
diseases, and is vital for the development of the bond
between mother and child. It has many other benefits.
Breastfeeding is especially vital in parts of the world where
water supplies are not safe and where impoverished families do not readily have the money to buy infant formula
and other infant and young child foods. This recommendation has a special significance. While derived from the evidence on being breastfed, it also indicates that policies and
actions designed to prevent cancer need to be directed
throughout the whole life course, from the beginning of
Cancer survivors are people who are living with a diagnosis of cancer, including
those who have recovered from the disease
This recommendation does not apply to those who are undergoing active
treatment, subject to the qualifications in the text
This includes all cancer survivors, before, during, and after active treatment
Subject to the qualifications made here, the Panel has
agreed that its recommendations apply also to cancer survivors. There may be specific situations where this advice
may not apply, for instance, where treatment has compromised gastrointestinal function.
If possible, when appropriate, and unless advised otherwise
by a qualified professional, the recommendations of this
Report also apply to cancer survivors. The Panel has made
this judgement based on its examination of the evidence,
including that specifically on cancer survivors, and also on
its collective knowledge of the pathology of cancer and its
interactions with food, nutrition, physical activity, and body
composition. In no case is the evidence specifically on cancer survivors clear enough to make any firm judgements or
recommendations to cancer survivors. Further details of
evidence and judgements can be found in Chapter 9.
Treatment for many cancers is increasingly successful,
and so cancer survivors increasingly are living long enough
to develop new primary cancers or other chronic diseases.
The recommendations in this Report would also be expected to reduce the risk of those conditions, and so can also be
recommended on that account.
The proposals that cancer might be preventable, and that
food, nutrition, physical activity, and body composition
might affect the risk of cancer, were first made before
science emerged in its modern form in the 19th and 20th
centuries. Throughout recorded history, wise choices of
food and drink, and of habitual behaviour, have been
recommended to protect against cancer, as well as other
diseases, and to improve well-being.
Reports such as this, which incorporate systematic
examination of all relevant types of research, differ from
ancient, historical, and even relatively recent accounts, and
descriptive studies of the type detailed in Chapter 1, not
only in the quantity and quality of evidence, but also in the
reliability of the judgements and recommendations that
derive from it.
T h e p u r p o s e o f t h i s R e p o rt
This Report has been commissioned and resourced by the
World Cancer Research Fund (WCRF) International and its
sister organisation the American Institute for Cancer
Research (AICR), who provided the Secretariat that has
supported the Panel responsible for the Report. Panel
members, observers, review centres, and other contributors
are listed on the preceding pages. The five-year project that
has resulted in this Report follows a previous five-year
project that resulted in the first WCRF/AICR report
published in 1997, which was the responsibility of the
former distinguished international multidisciplinary panel
chaired by Professor John Potter.
This Report has two overall general purposes. The first is
to summarise, assess, and judge the most comprehensive
body of evidence yet collected and displayed on the subject
of food, nutrition, physical activity, body composition, and
the risk of cancer, throughout the life-course. The second
purpose is to transform the evidence-derived judgements
into goals and personal recommendations that are a
reliable basis for sound policies and effective actions at
population, community, family, and individual level, in
order to prevent cancer, worldwide.
W h a t i s a l re a d y k n o w n
The Panel is aware of the general consensus shared by
scientists, health professionals, and policy-makers on the
relationships between food, nutrition, physical activity,
body composition, and the risk of cancer.
This consensus, based on the findings of a rapidly
growing mass of increasingly well-designed
epidemiological and experimental studies and other
relevant evidence, emerged in the early 1980s. Thus: 'It is
abundantly clear that the incidence of all the common
cancers in humans is determined by various potentially
controllable external factors. This is surely the most
comforting fact to come out of cancer research, for it
means that cancer is, in large part, a preventable disease'.1
This is the conclusion of a report on diet and the
prevention of cancer published a quarter of a century
before this Report.
Since the early 1980s, relevant United Nations agencies,
national governments, authoritative non-governmental
organisations, and researchers and other experts in the
field have agreed that food and nutrition, physical activity,
and body composition are individually and collectively
important modifiers of the risk of cancer, and taken
together may be at least as important as tobacco.
By the mid-1990s the general consensus became more
solidly based on methodical assessment of the totality of
the relevant literature. Thus: 'It is now established that
cancer is principally caused by environmental factors, of
which the most important are tobacco; diet and factors
related to diet, including body mass and physical activity;
and exposures in the workplace and elsewhere.' This
statement introduces the recommendations made in the
first WCRF/AICR report.
Expert reports may be accompanied by guidebooks
written for general readers. Thus: 'A healthy eating
strategy… is an important part of protecting yourself
against a long list of diseases. These include heart disease,
stroke, several common cancers, cataract formation, other
age-related diseases, and even some types of birth defects.
When combined with not smoking and regular exercise, this
kind of healthy diet can reduce heart disease by 80 per
cent, and stroke and some cancers by 70 percent, compared
with average rates'.2 This is a conclusion of a book written
by a member of the Panel responsible for this Report.
Some general judgements are now well known and not a
matter for serious debate. Cancer in general, and cancers
of different types and sites, are agreed to have various
causes, among which are inherited genetic predisposition
and the increasing likelihood that cells will accumulate
genetic defects as people age. This is discussed in more
detail in Chapter 2. Also, people die less frequently from
nutritional deficiencies, infectious diseases, predation, and
accidents, whereas chronic diseases including cancer —
which are more common in older people — become more
However, cancer is not an inevitable consequence of
ageing, and people's susceptibility to it varies. There is
abundant evidence that the main causes of patterns of
I N T R O D U C T I O N
cancer around the world are environmental. This does
indeed mean that at least in principle, most cancer is
preventable, though there is still discussion about the
relative importance of various environmental factors.
But what are these environmental factors, what is their
relative importance, and how may they vary in different
times in the life-course and in different parts of the world,
and how might they interact with each other? Many
thousand epidemiological and experimental studies have
looked for answers. Some answers are now agreed to be
unequivocal. Thus, smoking is the chief cause of lung
cancer. Alcohol is also an established carcinogen in
humans, as are types of radiation such as those used in
medical treatments and as released by nuclear weapons
and accidents. Certain infectious agents are undoubtedly a
cause of some cancers.
The need for a new initiative
Many questions, particularly in the field of food, nutrition,
and associated factors, remain. Some are fundamental. Do
statements such as those quoted above remain valid? Do
they apply worldwide? Have the reviews and reports so far
published overlooked key findings? How do the large
prospective studies, meta-analyses, pooling projects, and
randomised controlled trials undertaken and published
since the mid-1990s impact on earlier conclusions and
recommendations? Are there areas in this field that have
been neglected? Is entirely new evidence coming to light?
Questions such as these led to the commissioning of this
Report by WCRF/AICR in 2001. The Panel responsible for
the Report first convened in 2003, and has met twice a
year until 2007. The terms of reference accepted by the
Panel at its first meeting were to:
• Judge the reviews of the scientific and other literature
prepared for the Panel by the assigned review teams
• Devise a series of dietary, associated, and other
recommendations suitable for all societies, designed to
reduce the risk of cancer
• Evaluate the consistency between such
recommendations and those designed to prevent other
food-related diseases.
The Panel believes that these terms of reference have been
fulfilled. The public policy implications of the
recommendations made in this Report are the subject of a
further report, to be published in late 2008.
S p e c i a l f e a t u re s o f t h i s R e p o r t
This Report in part adapts and builds on the work of the
previous WCRF/AICR report. It also has central features
that are new. It is not simply an 'update' of the previous
report. Since the mid-1990s a substantial body of relevant
literature has been published in peer-reviewed journals.
Further, the executive officers of WCRF/AICR, its
Secretariat, and the Panel responsible, decided at the
outset that developments in scientific method since the
mid-1990s, notably in systematic approaches to
synthesising evidence, and as enabled by the electronic
revolution, have been so remarkable that a whole new
process was justified.
This process (described in Appendix A) has involved
systematic literature reviews (SLRs), which have been used
as the main basis for the Panel's judgements in this Report.
These are described in more detail in Chapter 3. They were
undertaken by independent centres of research and review
excellence in North America and Europe, to a common
agreed protocol, itself the product of an expert
Methodology Task Force. As a result, the judgements of the
Panel now are as firmly based as the evidence and the state
of the science allow. Some are new. Some are different
from those previously published. Findings that may at first
reading seem to repeat those of the first report are in fact
the result of an entirely new process.
Rigorous criteria to assess evidence
The criteria used in this Report to assess the evidence
presented in the SLRs and from other sources are more
precise and explicit than, and in some respects different
from and more stringent than, those used in the previous
report. During its initial meetings, the Panel reviewed and
agreed these criteria before embarking on the formal
evidence review. More details are given in Chapter 3.
Nevertheless, readers and users of this Report should be
able to see how and why the development of scientific
method and research since the mid-1990s has resulted in
conclusions and recommendations here that sometimes
vary from, sometimes are much the same as, and
sometimes reinforce those of the previous Report.
Graphic display of Panel judgements
The Panel has retained the matrix technique of displaying
its judgements, which introduce the chapters and chapter
sections throughout Part 2 of this Report. This technique,
pioneered in the first report, has been adapted by the
World Health Organization in its 2003 report on diet,
nutrition, and the prevention of chronic diseases. Some
members of the expert consultation responsible for the
WHO report, including its chair and vice-chair, have served
as members of the Panel responsible for this Report.
In further adapting the format of the matrices used in
the first report, the Panel was careful to distinguish
between evidence strong enough to justify judgements of
convincing or probable causal relationships, on which
recommendations designed to prevent cancer can be
based, and evidence that is too limited in amount,
consistency, or quality to be a basis for public and personal
health recommendations, but which may nevertheless in
some cases be suggestive of causal relationships.
Food-based approach
Since the 1990s a broad food- and drink-based approach to
interpreting the evidence on food, nutrition, and the risk of
cancer has increasingly been used, in contrast to the
overwhelming research emphasis on individual food
constituents. The previous report included three chapters
showing the findings on dietary constituents (including
'energy and related factors', notably physical activity),
foods and drinks, and food processing (meaning
production, preservation, processing, and preparation), in
that order.
This Report has taken a food-based approach, as shown
throughout Chapter 4, more closely reflecting the nature of
the evidence. Thus many findings on dietary constituents
and micronutrients, when their dietary sources are from
foods rather than supplements, are here identified as, for
example, findings on 'foods containing dietary fibre' or
'foods containing folate'. Findings on methods of food
processing are, wherever possible, shown as part of the
evidence on the associated foods, so that, for example,
meat processing is integrated with the evidence on meat.
The evidence and judgements focused on cancer are
summarised and displayed in Chapter 7.
The scope of the work of this Panel is wider than that of
the previous panel. The previous report judged that the
evidence that physical activity protects against cancer of
the colon was convincing. Since then evidence on physical
activity (and physical inactivity, especially when this
amounts to generally sedentary ways of life) has become
more impressive. Correspondingly, the review centres were
requested specifically to examine the literature on physical
activity (and inactivity) as well as on foods and drinks. The
results of this work, and the Panel's judgements, are shown
in Chapter 5.
As with physical inactivity, the evidence that body fatness
— including degrees of fatness throughout the range of
body weight, from underweight and normal to overweight
and obesity, as well as any specific effect of weight gain —
directly influences risk of some cancers has also become
more impressive. The previous report judged that the
evidence that greater body fatness (there termed 'high
body mass') is a convincing or probable cause of cancers of
the endometrium, breast (postmenopausal), and kidney.
For this Report, the commissioned SLRs not only included
the evidence linking body fatness directly with cancer, but
a separate review was also commissioned specifically on
the biological and associated determinants of body fatness
itself. The evidence and the Panel's judgements, which
include assessment of the physiology of energy
metabolism, are summarised in Chapters 6 and 8.
The Panel is aware that weight gain, overweight, and
obesity, and their antecedent behaviours, are critically
determined by social, cultural, and other environmental
factors. This is one topic for the separate report on policy
implications to be published in late 2008.
There are increasing numbers of cancer survivors — people
who have at some time been diagnosed with cancer. What
should those people living with cancer do? Particularly
since the 1990s, this question is being asked increasingly,
as more and more people are diagnosed with and treated
for cancer, and are seeking ways in which they can add to
their medical or surgical management to help themselves
to remain healthy. Are the circumstances of people who
have recovered from cancer any different from those of
people who are free from cancer? Questions such as these
are addressed in Chapter 9.
Life-course approach
Unlike this Report, the reviews conducted for the first
report did not consider the literature on food and nutrition
in the first two years of life. Increasingly, evidence is
accumulating on the importance of early life-events on
later health. Evidence and judgements on the impact of
birth weight and adult attained height on cancer risk are
presented in Chapter 6, though the detailed processes
underpinning these associations with cancer risk are not
yet clear. Findings on the relationship between not being
breastfed and later overweight and obesity in children are
reported in Chapter 8, and on lactation and lower breast
cancer risk in the mother are reported in Chapter 7. These
findings form part of a general 'life-course' approach
summarised in Chapter 2, reflecting an appreciation of the
importance of the accumulation of nutritional and other
experiences throughout life, as well as genetic endowment,
in influencing susceptibility to disease.
Goals and recommendations
The Panel's recommendations are set out in Chapter 12
and in abbreviated form in the Summary, on the preceding
pages.
The previous report agreed 14 recommendations. This
Report makes eight general and two special
recommendations for specific target groups. These are set
out in more detail than in the previous report. As before,
principles that guide the goals and recommendations are
set out. The recommendations themselves are displayed in
boxes and are accompanied by text that justifies them, and
by practical guidance. The recommendations are addressed
to people, as members of communities and families and
also as individuals.
Recommendations and options addressed to UN and
other international organisations, national governments,
industry, health professional and civil society organisations,
and the media are set out in the separate report on policy
implications, to be published in late 2008.
scale this represents over 3 to 4 million cases of cancer that
can be prevented in these ways, every year.
In many of its forms, cancer is a disease that can cause
great suffering and claims many lives. The overall
commitment of scientists and other professionals
committed to disease prevention, as exemplified by this
Report, is to reduce the rates not just of cancer, but of all
diseases, so that more people enjoy good health until they
eventually die in old age.
A note of caution
The Panel is confident that its findings are soundly based,
and that its recommendations, when translated into
effective public policy programmes and personal choices,
will reduce the risk of cancer. That said, the available
evident is imperfect. The Panel's conclusions derive from
the best evidence now available, which reflects past and
recent research priorities mostly in high-income countries,
though synthesised and judged in as meticulous and
rigorous way as possible. What is here is therefore an
incomplete picture.
The tendency of reports such as this is to consider
diseases in isolation. In the case of this Report, the
relationship of weight gain, overweight, and obesity on the
risk of some cancers is so clear that determinants of these
factors have also been considered. But the Panel agrees, as
evident in Chapters 10 and 12, that many chronic diseases,
including type 2 diabetes and its precursors, cardiovascular
diseases and their precursors, and also perhaps other
diseases of the digestive, musculoskeletal, and nervous
systems, are to a large extent caused by environmental
factors, including inappropriate food and nutrition,
physical inactivity, overweight and obesity, and associated
factors. Following from this, future reports should consider
the promotion of health and the prevention of disease as a
National Research Council. Diet, Nutrition and Cancer. Washington
DC: National Academy of Sciences, 1982
Willett W. Summary. In: Eat, Drink, and Be Healthy. The Harvard
Medical School Guide to Healthy Eating. New York: Free Press, 2003
Doll R, Peto R. The causes of cancer: quantitative estimates of
avoidable risks of cancer in the United States today. J Natl Cancer Inst
1981;66:1191-308.
H o w m u c h c a n c e r i s p re v e n t a b l e ?
As shown in its title, the purpose of this Report is to
prevent cancer. The term 'prevention' needs definition. It
does not mean the elimination of cancer. It means
reduction in its occurrence, such that at any age fewer
people have cancer than otherwise would be the case.
If all factors are taken into account, cancer is mostly a
preventable disease. The authors of a landmark study
published in the early 1980s concluded: 'It is highly likely
that the United States will eventually have the option of
adopting a diet that reduces its incidence of cancer by
approximately one third, and it is absolutely certain that
another one third could be prevented by abolishing
smoking.'3 Cancers of some sites, notably of the colon, are
generally agreed to be greatly or mostly affected by food
and nutrition.
Since then, authoritative estimates of the preventability
of cancer by means of food and nutrition and associated
factors have been in broad agreement with the 'around one
third' figure. The estimate of the previous WCRF/AICR
Report was that cancer is 30 to 40 per cent preventable
over time, by appropriate food and nutrition, regular
physical activity, and avoidance of obesity. On a global
> VŽ } Àœ Õ ˜ `
International variations and trends
The cancer process
P A R T
Introduction to Part 1
This Report has a number of inter-related general purposes. One is to explore
the extent to which food, nutrition, physical activity, and body composition
modify the risk of cancer, and to specify as far as possible the importance of
specific factors. To the extent that environmental factors such as food,
nutrition, and physical activity influence risk of cancer, it is a preventable
disease. The Report specifies recommendations based on solid evidence
which, when followed, will be expected to reduce the incidence of cancer.
Part 1 of the Report begins with two chapters summarising the first lines of
evidence from observations of human populations, and from experimental
and basic science, pointing to the conclusion that cancer is preventable. The
third chapter summarises the types of evidence that are relevant in
identifying the causes of cancer, and explains the process used by the Panel
to assess the strength of this evidence and to come to judgement.
Chapter 1 shows that patterns of production and consumption of food and
drink, of physical activity, and of body composition have changed greatly
throughout different periods of human history. Remarkable changes have
taken place as a result of urbanisation and industrialisation, at first in
Europe, North America, and other economically advanced countries, and
increasingly in most countries in the world.
With the establishment of reliable records in the second half of the 20th
century, notable variations have been identified in patterns of cancer
throughout the world. Some cancers, such as those of the upper
aerodigestive tract, stomach, liver, and cervix, are more common in lower
income countries; others, such as those of the colorectum, breast, ovary,
endometrium, prostate, and lung, are more common in higher income
More significant, as shown in Chapter 1, are studies consistently showing
that patterns of cancer change as populations migrate from one part of the
world to another and as countries become increasingly urbanised and
industrialised. Projections indicate that rates of cancer in general are liable
Chapter 2 outlines current understanding of the biology of the cancer
process, with special attention given to the ways in which food and
nutrition, physical activity, and body composition may modify it.
Cancer is a disease of genes, which are vulnerable to beneficial or harmful
mutation, especially over the long human lifespan. Nutritional factors are
important in determining the likelihood of some mutations, as well as in
changing the functions of genes even without mutation. However, both
epidemiological and experimental evidence shows that only a small
proportion of cancers are inherited. Environmental factors are most
important and can be modified. These include smoking and other use of
tobacco; infectious agents; radiation; industrial chemicals and pollution;
medication — and also many aspects of food, nutrition, physical activity, and
body composition. Essentially this is good news. It means that healthy
environments can stop cancer before it starts. The evidence also indicates that
such environments, including the factors that are the subject of this Report,
may be able to check the cancer process after it has started.
The third chapter summarises the types of evidence that the Panel has agreed
are relevant to its work. No one study can prove that any factor definitely is a
cause of or is protective against any disease. Also while some study designs
are more reliable than others, they often cannot be used to answer many types
of question; so no one kind of study, however careful its methods, can ever
produce definitive results. In this chapter, building on the work of the first
report, the Panel shows that all study designs have strengths and weaknesses,
and that reliable judgements on causation of disease are based on assessment
of a variety of well designed epidemiological and experimental studies.
The judgements made by the Panel in Part 2 of this Report are based on
independently commissioned and conducted systematic reviews of the
literature. This has ensured that the evidence has been assembled using
methods that are as meticulous as possible, and that the display of the
evidence is separated from assessments derived from this evidence, which are
made in Part 2.
The prevention of cancer worldwide is one of the most pressing challenges
facing scientists and public health policy-makers, among others. These
introductory chapters show that the challenge can be effectively addressed.
They also suggest that food and nutrition, physical activity, and body
composition all play a central part in the prevention of cancer.
C H A P T E R
B A C K G R O U N D
and trends
The first lines of evidence suggesting that cancer is
a largely preventable disease have come from
studies noting variations in cancer incidence across
time and place. The most impressive initial evidence
showing that patterns of cancer are altered by
environmental factors, and are not mainly
genetically determined, comes from studies
describing changes in the rates of different cancers
in genetically identical populations that migrate
from their native countries to other countries. Such
studies consistently show that changes in the rates
of some of the most common cancers, including
those of the stomach, colorectum, breast, and
prostate, can be remarkable, even over one or two
generations.
This first introductory chapter summarises current
knowledge of the variations in food, nutrition,
physical activity, body composition, and cancer in
different parts of the world. This assessment
provides strong circumstantial evidence that
continues to prompt systematic studies including
interventions of various types, and also reports such
as this, which collect and judge the available
evidence. Such systematic work has already led the
United Nations and other international bodies,
national governments, and authoritative
independent organisations to be confident that
most cancers are largely preventable.
Patterns of food and drink, of physical activity,
and of body composition have changed remarkably
throughout human history. With industrialisation
and urbanisation, food supplies usually become
more secure, and more food is available for
consumption. In general, diets become more energy
dense, containing fewer starchy foods, more fats
and oils, sugars, and additives, and often more
alcoholic drinks. At the same time, patterns of
physical activity change: populations become
increasingly sedentary, their need for energy from
food drops, and rates of overweight and obesity
increase.
These changes correlate with changes in the
patterns of cancer throughout the world. Middleand low-income regions and countries within Africa,
Asia, and Latin America have generally experienced
comparatively high rates of cancers of the upper
aerodigestive tract (of the mouth, pharynx, larynx,
nasopharynx, and oesophagus), and of the stomach,
liver (primary), and cervix. Rates of some cancers,
especially stomach cancer, are now generally
decreasing.
In contrast, high-income countries, and urbanised
and industrialised areas of middle- and low-income
regions and countries, have higher rates of
colorectal cancer and of hormone-related cancers (of
the breast, ovary, endometrium, and prostate). Lung
cancer is now the most common type in the world
because of the increase in tobacco smoking and
exposure to environmental tobacco smoke. Rates of
these cancers, some of which may have been
historically rare, are increasing.
Globally, the number of people with cancer is
projected to double by the year 2030, with most of
this increase likely to occur in middle- and lowincome countries. Such an increase would only
partly be accounted for by the projected rise in the
size and average age of the global population. This
makes the task of cancer prevention all the more
urgent and important.
I N T E R N AT I O N A L
V A R I AT I O N S
This chapter outlines the historic, recent, and current variations and trends in food, nutrition, physical activity, overweight and obesity, and in patterns of cancer.
People's diets reflect the times and situations in which they
live. It is only relatively recently in history that urban–industrial ways of life have evolved, with many or most people
living in towns and cities rather than in the countryside. In
much of Africa and Asia, most people still live in rural communities, and peasant–agricultural and urban–industrial
ways of life still coexist in most countries. Such patterns
change very rapidly as countries become increasingly
urbanised and industrialised.
The different food systems and diets that are part of these
diverse ways of life affect people's levels of physical activity,
their body composition and stature, their life expectancy, and
patterns of disease, including cancer. With the move to
urban–industrial ways of life, populations have become taller
and heavier, their life expectancy has increased, and they are
usually adequately nourished (although poverty, and even
destitution, remains a major problem in most big cities). On
the other hand, urban populations are at increased risk of
chronic diseases such as obesity, type 2 diabetes, coronary
heart disease, and also some cancers.
This chapter also summarises some available information
on eight common cancers, irrespective of any recognised links
to food, nutrition, and physical activity; these factors are dealt
with later in the Report. Four are endemic in middle- and lowincome countries: cancers of the oesophagus, stomach, liver,
and cervix. Four are endemic in high-income countries, and
are in general increasing in middle- and low-income countries:
cancers of the lung, colon and rectum, breast, and prostate.
Information on the trends and projections of levels of physical activity, and overweight and obesity, is summarised.
Descriptive epidemiology, including studies of changing disease patterns in migrant populations, is covered. These studies can generate hypotheses about relationships between food,
nutrition, physical activity, and the risk of cancer. However,
they serve mainly as a foundation for studies that provide
stronger evidence.
The 12 national examples provided throughout this chapter summarise some of the trends in foods and drinks, obesity, physical activity, and cancer in countries around the world.
These are Egypt and South Africa (Africa); China, India, and
Japan (Asia); the UK, Poland, and Spain (Europe); the USA,
Brazil, and Mexico (the Americas); and Australia (AsiaPacific).1-47
A N D
T R E N D S
1.1 Food systems and diets: historical and
Throughout history, food systems, and thus human diets,
have been and are shaped by climate, terrain, seasons, location, culture, and technology. They can be grouped into three
broad types: gatherer–hunter, peasant–agricultural, and
urban–industrial. These and other food systems (for example, pastoralist, the semi-mobile farming of herds of large
animals such as sheep and cattle) have their roots in history. All have coexisted in recent millennia with the exception
of industrial food systems, which are the consequence of the
industrial revolution that began in Europe in the late 18th
century. These systems still exist in the world today.
1.1.1 Gatherer–hunter
Since the emergence of Homo sapiens around 250 000 years
ago, gatherer–hunter food systems have taken different
forms, depending on the environments in which people lived.
These systems still exist in parts of the world that are remote
from cities and roads. They supply diets that usually include
moderate amounts of starchy foods, and which are high in
dietary fibre and low in sugar, mostly from fruits and
honey.48 Methods of food preparation include pulverising,
drying, and roasting. These diets are usually high in foods
of animal origin (ranging from large animals to insects, and
also fish and other seafood, depending on location), and
thus in animal protein. It is sometimes thought that
gatherer–hunter diets are high in fat, which is not the case
because wild animals are lean. Recent analyses suggest that
gathered food generally provides rather more dietary bulk
and energy than hunted food.49
People in gatherer–hunter societies are necessarily physically active, and are often tall and usually lean (only chiefs,
or old or incapacitated people might be overweight or
obese). The diets of food-secure gatherer–hunter societies
may be diverse and high in micronutrients.50 51 Diets are
liable to become monotonous and deficient in various nutrients, as well as in energy, when food supplies are chronically
insecure, or at times of acute food shortage. It is sometimes
claimed that gatherer–hunter food systems generate diets to
which the human species is best adapted.48 However, life
expectancy in gatherer–hunter societies is and has been usually relatively low.
Evidence of cancer has occasionally been found in human
and other fossil and ancient remains.52 Historically, cancer
In 2004 Egypt had a population of just over
74 million. Nearly the whole population
lives within the Nile Valley and the Nile
Delta, less than 4 per cent of the country's
total area. Egypt has a lower-middle-income
economy, with a gross domestic product of
4274 international dollars per person (figure
1.3). Life expectancy at birth is 66 years for
Non-communicable causes of death
men and 70 for women (figure 1.1).46
Chronic diseases account for 83.6 per
cent of deaths, while infectious diseases,
maternal, perinatal, and nutritional condi-
Age-standardised rates of common cancers
Age-standardised rate per 100 000
Per cent of deaths
Data from World Health Organization46
of any type seems to have been uncommon among gatherer–hunter peoples, if only because their average life
expectancy was low. In modern gatherer–hunter societies,
the incidence of cancer rises after contact with industrialised
and urbanised ways of life, which usually involve shifts in
patterns of diet and physical activity.53 These points generally also apply to pastoralist societies.
1.1.2 Peasant–agricultural
In recent millennia, and until very recently in history, almost
all human populations have been rural and mostly peasant–agricultural, and the majority still are in most regions of
Asia, many regions of Africa, and some parts of Latin
America. Peasant–agricultural food systems involving the cultivation of wheat may have first developed around 9000
years ago in the 'Fertile Crescent' of the Middle East, including the region between the Tigris and Euphrates rivers (within modern Iraq). These systems also developed
independently in Asia, with rice as the staple food, and in
the Americas, with corn (maize) as the staple.54 The key factor in these systems is land settlement, itself determined by
the cultivation and breeding of crops and also animals, birds,
and fish for human consumption and use.55 In and around
Egypt, people began to make bread from wheat about 6000
years ago.56
Typically, diets derived from these systems are plant-based:
they are high or very high in cereals (grains), complemented with animal sources of protein. These diets are therefore
high in starchy foods and usually in dietary fibre (unless the
Data from International Agency for Research on Cancer20
cereals are refined). They include varying amounts of foods
of animal origin, and of vegetables and fruits, depending on
relative food security. Surplus food is stored for consumption in winter and during hard times, and methods of food
preparation also include fermentation, used for foods as well
as for the production of alcoholic drinks (see chapters 4.8
and 4.9).
The dominant indigenous cereal crop varies in different
parts of the world: wheat is grown in the Middle East; barley, rye, and oats in colder, northern climates; millet and rice
in Asia; maize (corn) in the Americas; and sorghum and teff
in Africa. Indigenous staple crops also include roots and
tubers such as cassava (manioc), yams, potatoes, and also
plantains. Pulses (legumes) are also farmed to ensure agricultural and nutritional balance; and other crops such as
vegetables and fruits are also cultivated. Birds and animals
are domesticated and bred for food, and fish and seafood
contribute to the diets of communities living beside water.57
As with gatherer–hunters, the diets of peasant–agricultural societies may be diverse and high in micronutrients.
Again, when food supplies are chronically insecure, or at
times of acute food shortage (including times of war), diets
are liable to become monotonous and deficient in various
nutrients, as well as in energy.
Peasant–agricultural societies are necessarily physically
active, although not constantly so: the main times of intensive physical work include building field systems, sowing,
harvesting, and storing. The level of energy balance and of
physical activity varies greatly, depending in part on how dif-
tions account for 12.2 per cent; 4.2 per cent
of deaths are due to injuries. The first figure gives a breakdown of deaths caused by
chronic diseases.46
Bladder cancer is the most common type
of cancer in men, followed by cancers of the
lung and liver.20 In women, the dominant
cancers include those of the breast, cervix,
and bladder (for age-standardised rates of
these cancers, see the second figure).20 The
high incidence of bladder cancer is likely to
be related to bilharzia, a parasitic infection
of the bladder.20 There is also a high incidence of hepatitis C virus, a cause of liver
cancer.20 Also see box 7.8.1 It is predicted
that there will be a 3.5-fold increase in liver
cancer by 2030.12
For the period 1991–1994, 46 per cent of
men and 48 per cent of women between
the ages of 20 and 44 were classified as
sedentary.46 In 2003, women aged 15–49
had a mean body mass index (BMI) of 28.6.
In teenagers (13–19 year olds), average BMI
was 23.9; women in their 30s had a mean
BMI of 29.0, while those over 45 had a BMI
of 31.3. In total, 77.3 per cent of women
aged 15–49 had a BMI of over 25. In 1992,
23.5 per cent of all women had a BMI of
over 30. By 2000, this figure had risen to 41
per cent.46 Fewer data are available for
men, but in 1994, the mean BMI for men
26.6,
to 28.4 for men over 45. In 2002, among
all men, 45 per cent had a BMI of between
25 and 29.99 and 20 per cent had a BMI of
over 30.15 See figure 1.4 for projections of
the proportions of men and women predicted to have a BMI of 30 or more in
The average amount of available food
energy rose between 1964 and 2004, from
around 2240 to 3290 kcal/person per day
(9400 to 13 800 kJ/person per day).1 Early
dietary studies in Egypt demonstrated that
corn bread was the staple food and that
protein intake was about 100 g/day.15
People from higher-income households
consumed more dairy products and those
from urban households consumed a wider
variety of foods. Between 1950 and 1990,
there was a shift towards a dependence on
wheat rather than other cereals (grains),
and a sustained rise in the consumption of
meat, fish, and dairy products.15
ficult it is to cultivate the land. The degree of physical activity and so of body mass in peasant–agricultural communities depends mostly on relative food security.58
People in these societies who are prosperous, especially
those who own land farmed by others, may quite often
become overweight or obese. But in general, and largely
because of the nature of their dietary staples, peasant–agriculturalists are usually short and lean. This is still evident in
rural peasant communities whose food systems remain traditional: for instance, in Africa, Latin America, and in Asia,
notably India and China.58
Agriculture enabled the development of towns and then
cities: throughout the world, walled, urban settlements
became surrounded by fields cultivated by peasants. These
people subsisted on the food they produced, and the surplus
fed the community living within the walls. In times of war,
the fortified settlement became a refuge for the farmers. This
crowding of populations into towns and cities caused a sharp
rise in the rates of infectious diseases, mostly notably among
infants and young children, pregnant and lactating women,
and infirm and old people.59
The average life expectancy of peasant–agriculturists
in general is probably a little longer than that of
gatherer–hunters, with a greater percentage of people
surviving into what would be regarded as late-middle and
old age.
The prevalence and incidence of various cancers in traditional rural societies is often uncertain, even following the
establishment of cancer registers in many countries: records
Consumption of sugars and oils increased
substantially
(legumes)
decreased in importance.15 Since the 1970s,
consumption of all major food groups has
increased. However, between 1990 and
1994 there was a 20 per cent decrease in
total household food consumption, because
subsidies were removed and food prices
rose sharply.15 A national study in 1981
found that only 24 per cent of urban and
15 per cent of rural households ate readymade foods, and meat was eaten more frequently in urban households compared
with rural households.15 A repeat survey in
1998 found that poultry had become the
main source of animal protein and that
wheat bread was the most popular type,
although homemade wheat-maize bread
was common in rural areas. Another study
highlighted differences in dietary fat
intake: in urban women, 27.5 per cent of
dietary energy came from fat (mainly as
vegetable oil) compared with 22.5 per cent
in rural women.15 Between 1981 and 1998,
people increasingly ate meals away from
home (20.4 per cent of all meals in 1981
compared with 45.8 per cent in 1998).15
are less reliable than those kept in urbanised societies. But
there is reasonable evidence that relatively common cancers
in peasant–agricultural societies include those causally
associated with chronic infections, such as cancers of the
stomach, liver, and cervix.60
1.1.3 Urban–industrial
Indigenous or traditional peasant–agricultural systems have
coexisted with urban–industrial food systems in most countries since the creation and growth of cities, and the beginning of the 'industrial revolution'. This movement started in
Europe in the 18th century, and then spread to North
America and elsewhere. Britain is one exception to this coexistence: it was the first country to become mostly urban, with
hired workers replacing peasants on increasingly large and
relatively mechanised farms. The Americas are another
exception: settlers, mostly from Europe, displaced native
populations and developed mechanised agricultural systems.61 In continental Europe, some balance between rural
and urban ways of life has been preserved. Throughout the
Mediterranean coastal regions, and in the Middle East, modern food systems have deep, historical roots.62 In most of
Africa and Asia, including countries with large cities, the
basic economies and cultures have remained predominantly
rural, but this is changing.63
Urban–industrial food systems have characteristics distinct
from peasant–agricultural and gatherer–hunter systems.
Their original purpose was to ensure reliable and adequate
supplies of food of an agreed minimum nutritional quality
In 2001 South Africa had a population of
nearly 47.5 million.3 The country has a middle-income economy, with a gross domestic
product of 8506 international dollars per
person (figure 1.3), which masks extreme
socioeconomic inequalities.46 Life expectancy at birth is 47 years for men and 49 for
women (figure 1.1).46
Chronic diseases account for 53.9 per cent
of deaths, while infectious diseases, maternal,
perinatal, and nutritional conditions account
for 40.2 per cent; 5.9 per cent of deaths are
due to injuries. The figure below gives a breakdown of deaths caused by chronic diseases.46
The most common cancers in men are
those of the prostate, lung, oesophagus,
colorectum, and bladder.20 Since HIV and
AIDS became epidemic, Kaposi's sarcoma
has become more common in both men
and women. For women, the most common
cancers are those of the cervix, breast,
Age-standardised rates of
common cancers
to entire populations. Technology has been the main driving
force behind these systems. For instance, various food-preservation techniques were developed as part of the industrial
revolution, and there has been further innovation since that
time. These include bottling, canning, refrigeration, and
packaging; the extensive use of sugar and salt; and technologies that suppress, convert, or eliminate perishable qualities in fresh foods (see chapters 4.6 and 4.9). The clearing
of land to rear cattle and sheep, and the development of railways, refrigeration, and other technologies, have made meat,
milk, and their products cheap and plentiful all year round.
Sugar derived from cane is the most profitable edible cash
crop, and sugars and syrups made from cane, beet, and now
also corn are used to sweeten and preserve breakfast foods,
baked foods, desserts, soft drinks, and a vast array of other
manufactured products.64 65 Steel roller mills, invented in the
1870s, separate the components of wheat and enable production of uniform quality white bread, which has become
a staple food.66 Hydrogenation, which converts oils to hard
fats (see chapter 4.5), has made margarine a basic item of
food, and provides ingredients used in the manufacturing of
many processed foods.67 Perhaps the most remarkable
change following the industrialisation of food systems has
been the precipitate drop in breastfeeding.68 At various times,
urban–industrial food systems have been adjusted in
response to the then current knowledge of nutrition and pub-
Colorectum
Kaposi's
lic health recommendations, notably when food security has
been threatened by wars.69
Urban–industrial food systems generate relatively energydense diets. These are fairly high in meat, and milk and their
products, and in total fats, hardened fats, processed starches and sugars, salt, baked goods, soft drinks, and often also
alcoholic drinks. These diets are relatively low in both
dietary fibre and starchy staple foods, other than products
made from wheat, which has become the dominant cereal
in most countries outside Asia and Africa. Recent advances
in food technology have further altered patterns of food production and consumption, particularly in high-income
countries. Patterns of production and consumption of
vegetables and fruits and fish vary between different
urban–industrial food systems, depending on factors such as
climate and geographical location.70
Efficient urban–industrial food systems can ensure the
constant supply of food to all sections of the population,
even to the lowest-income and marginalised groups. In higher-income countries and regions, this, together with basic
public health initiatives, has helped to greatly reduce rates
of nutritional deficiencies and other diseases, which people
are more vulnerable to if they have inadequate food supplies.
As a result of these food systems, people have become generally taller and heavier.
Since the industrial revolution, as populations have moved
colorectum, lung, and oesophagus (for agestandardised rates of these cancers, see the
second figure).20 Diseases of poverty and
chronic diseases coexist, but it is predicted
that by 2010, deaths from AIDS will account
for twice as many deaths as those from all
other causes combined.5 41
men and 49 per cent of women aged 18–69
were classified as sedentary (figure 1.6).46
Some regional studies suggest that young
women who did not finish school have low
levels of physical activity.24 There is a lack of
physical education in schools, and poor
environment and high crime rates prevent
leisure activity outside school.24
In 1998 men aged 15–24 had an average
body mass index (BMI) of 21.1; for those
aged 35–65, average BMI remained constant at around 25. Just 7.8 per cent of men
aged 25–34 had a BMI of over 30 compared
with 17.3 per cent of men aged 45–54. In
the same year, women aged 15–24 had an
average BMI of 23.7; for those aged 35–64,
average BMI remained constant at around
29. In women aged 25–34, 27 per cent had
a BMI of over 30 compared with 45 per cent
of women aged 45–64.46 Although undernutrition remains a problem among rural
children, obesity and associated diseases are
also prevalent. There has been a misconception of 'benign obesity': being thin is
associated with HIV and AIDS, and moderately overweight women are thought of as
attractive and affluent.24 Overall, in 1998,
21.1 per cent of men and 25.9 per cent of
women had a BMI of at least 25; 10.1 per
cent of men and 27.9 per cent of women
had a BMI of at least 30. See figure 1.4 for
projections of the proportions of men and
women who will have a BMI of 30 or more
(11 400 to 12 600 kJ/person per day). In the
same period, sugar consumption dropped
from 420 to 370 kcal/person per day (1800
to 1500 kJ/person per day).1 The National
Food Consumption survey of 1999 found
that stunting was the most common nutritional disorder, affecting almost one fifth of
children aged 1–9, with the lowest levels in
urban areas. There was a similar pattern for
underweight, where 10 per cent of children
aged 1–3 consumed less than half of their
suggested daily dietary needs, and 26 per
cent consumed less than two thirds.25 In
rural areas, adults from lower-income
households were shorter and had a lower
Life expectancy at birth
BMI, and commonly consumed foods were
maize, sugar, tea, milk, and brown bread.
Urban households ate less maize porridge
but more vegetables and fruits, animalbased products, and fats and oils. It was
only in urban areas that fruits and milk
appeared in the top 10 list of foods and
drinks consumed by more than 85 per cent
of people. In men, alcoholic drinks made a
significant contribution to dietary energy
(10–14 per cent). People living in rural areas
obtained a higher proportion of total
dietary energy from carbohydrates, whereas the most urbanised populations derived
one third of their energy from animal foods
Urbanisation is generally accompanied
by an improvement in micronutrient
intakes, but this way of life is also associated with increases in overweight and obesity.44 Other studies have suggested shifts
towards a Western dietary pattern in people living in both urban and rural areas, typified by a decrease in starchy foods and
dietary fibre consumption, and an increase
in fat. They have also shown that half of
the population does not eat the locally
recommended four portions of fruits
and vegetables each day, while a quarter
eats none.10
from rural to urban areas, there have been rapid and profound changes in both the nature and quality of their foods
and drinks, and the patterns of diseases they suffer.71
Urban–industrial food systems have evidently improved people's strength and health in early life. They are also a factor
in the doubling of average life expectancy since 1800, and
the increase in global population from around 1 billion in
1800 to 6.5 billion in 2006.72 The range of current life
expectancy in selected countries is illustrated in figure 1.1.
In the second half of the 20th century, attention focused
on the apparent ill-effects of these food systems on people,
mostly in later life. By the 1980s, it was generally agreed that
these industrialised diets increase the risk of some chronic
diseases, usually of later life, which had become common or
epidemic in higher-income industrialised countries. These
included obesity, type 2 diabetes, and coronary heart disease.
At the same time, in examining patterns of both diet and cancer across the world, and among migrants, it was increasingly thought that these diets were partly responsible for
some cancers, notably those of the colon and rectum, breast,
ovary, endometrium, and prostate.73-75
In the last decades of the 20th century, the demographic,
nutritional, and epidemiological transitions that had, until
then, largely been apparent only in higher-income countries
became global. Since the 1990s, and outside Europe, North
America, and other high-income countries, economic glob-
In 2004 China had a population of over 1.3
billion. The one-child policy introduced in
1979 has reduced annual population
growth to 1.07 per cent. The United Nations
estimates that the population will have
increased to nearly 1.5 billion by 2025.46 The
country has a lower-middle-income economy, with a gross domestic product of 5581
international dollars per person (figure
2004 found that there has been a shift
towards nutrition-related chronic diseases
such as type 2 diabetes, cancer, and cardiovascular disease.14
Stomach cancer is the most common type
of cancer in men, although it has declined
slightly since 1980.20 Lung cancer has risen
steadily over the same period.20 Liver cancer
has risen since 1990, although levels are now
of deaths, while infectious diseases, maternal, perinatal, and nutritional conditions
account for 11.7 per cent; 9.3 per cent of
deaths are due to injuries.46 The figure
below gives a breakdown of deaths caused
by chronic diseases.46 A study published in
alisation is thought to be the single main force shifting
populations from the countryside into cities, changing the
dominant food systems from peasant–agricultural to
urban–industrial, and transforming patterns of disease. This
phenomenon includes the unprecedented and accelerating
movement of money, goods, and ideas. All this has been
made possible by new international, political, and economic policies, by the creation of supranational regulatory bodies such as the World Trade Organization, and by the
electronic revolution.76-78
People's levels of physical activity have also changed dramatically as a result of the move from peasant–agricultural
to urban–industrial ways of life. In 1950, the UN 'reference
man' weighing 65 kg (143 lbs) was estimated to be in energy balance at an average of 3200 kilocalories (kcal)/day
(13398 kilojoules [kJ]/day); the 'reference woman' weighing
55 kg (121 lbs) was estimated to be in energy balance at 2300
kcal/day (9630 kJ/day). Today in the USA, average weights
are much higher, yet the figure for the 'reference person' (men
and women combined) is taken to be 2000 kcal/day (8374
kJ/day) for the purposes of nutrition food labelling. The reason for this drop in human energy requirements is because
three of the four settings for physical activity — occupational, household, and transport — (see Chapter 5) have become
increasingly mechanised. Energy-dense food systems, essen-
tial to sustain young populations that walk or cycle to work
that is physically demanding, are unsuitable for ageing populations who sit for most of the day, even if they engage in
some recreational physical activity.
There is some evidence that these very recently introduced
urban–industrial food systems have lowered the rates of
nutritional deficiencies and infectious diseases of early life
in middle- to low-income countries and regions. But the
apparent impact on the rates of chronic diseases in these
areas is of increasing public health concern. In most of these
regions, with the exception of sub-Saharan Africa, childhood
overweight, obesity, and type 2 diabetes have become common and, in some countries, epidemic.70
The Panel emphasises that there is no reason to think that
urban–industrial food systems are intrinsically harmful. They
were first developed using relatively crude technologies, and
at a time when something was known of their positive
impact on growth and strength, but little of their long-term
impact on health. Since then, many new technologies have
been developed, and there is a clearer understanding that
some methods of preserving and processing food are beneficial, whereas others are a factor in increasing the risk of
disease. Future developments can ensure universal food
security, avoid earlier mistakes, and reduce the risk of chronic diseases, including cancer.
stabilising.20 The incidence of cancer of the
oesophagus has remained stable since the
1980s and cancers of the colorectum are also
relatively common.20 For women, the most
common cancers are those of the lung,
stomach, and breast, which have risen
steadily since the 1980s; of the liver, which
has risen since 1990; and of the oesophagus.
For age-standardised rates of these cancers,
see the second figure.20
These figures are likely to increase, with further urbanisation and greater use of vehicles for transport. Between 1980 and 2003,
the number of cars produced in China
quadrupled to more than 2 million.84
body mass index (BMI) of around 25; just 2.1
per cent of men aged 20–74 had a BMI of
over 30. In the same year, women aged
25–29 had an average BMI of 22.2, and
those aged 35–64 had a BMI of around 25.
Just 3.7 per cent of women had a BMI of
over 30.46 In 2002, 18.9 per cent of men and
women aged 18 and above had a BMI of
over 25, and 2.9 per cent of them had a BMI
of over 30. See figure 1.4 for projections of
the proportions of men and women who
will have a BMI of 30 or more in 2015.
(7760 to 12 290 kJ/person per day). This is
largely due to an increase in the availability of fats and oils, meat, and sugar.1 The
1957–1962 famine was followed by a liberalisation of food production. Economic
growth has reduced poverty and Chinese
diets now are influenced by the Western
pattern: cereals (grains) and lower-fat mixed
dishes are being replaced with animal foods
and edible fats.14 Recent national nutritional surveys show that energy intake from animal sources increased from 8 per cent in
1982 to 25 per cent in 2002, and that energy from fat, particularly among people living in urban areas, increased from 25 to 35
per cent over the same period.84 Intake of
cereals (grains) has also decreased substantially since the mid-1980s among urban and
rural populations, with a larger decrease in
the consumption of coarse grains compared
with refined varieties. The biggest drop in
cereal intake has been among people in the
lowest-income groups. Vegetable and fruit
intakes have decreased since 1989, although
they are highest in urban populations. Fat
intake is also increasing and many adults
obtain 30 per cent or more of their overall
energy intake from fat.14 Regional variations also exist: for example, the dietary pattern around the city of Hangzhou is very
1.2 Foods and drinks, physical activity,
1.2.1 Foods and drinks
Substantial changes have occurred in the patterns of foods
and drinks supplied and consumed throughout the world,
and these changes are becoming increasingly rapid. Also see
Economic development is generally accompanied by
quantitative and qualitative changes in food supplies and
therefore in diets. This 'nutrition transition' may reduce the
risk of some dietary deficiencies and improve overall nutrition. But it can also be accompanied by adverse shifts in the
composition of diets, for instance, with a greater proportion
of energy coming from fats and oils, and added sugars. Over
recent years, such dietary changes have been rapid in the
middle- and low-income countries of Asia, Africa, the Middle
East, and Latin America.63 79 80
The Food and Agriculture Organization (FAO) of the UN
records global differences in the availability of food crops and
commodities (box 1.1). These data provide information on
the average amounts of food available for consumption,
rather than actual food consumption. Animal products have
traditionally made up a small proportion of food availability in low-income countries; most dietary energy comes from
varied, resulting in a diet low in saturated
fatty acids and high in n-3 polyunsaturated
fatty acids; people there eat green, leafy
vegetables with almost every meal.26 The
incidence of nutrition-related diseases and
deaths from these diseases are lower in this
region than in other parts of China.
Snacking contributes minimal energy
intake to Chinese diets (0.9 per cent).
However, snacking and eating food away
from home are increasing among children
from middle- and high-income groups.
Foods commonly eaten away from home
include cereals (grains), vegetables and
fruits, meat, eggs, and fish. Between 1991
and 1997, the proportion of children from
low-income households eating foods away
from home did not change, but there was
an increase among children from higherincome groups, with a 10 per cent increase
in the consumption of foods from animal
sources eaten away from home. Eating food
prepared away from home accounted for 15
per cent of total energy intake for all
Chinese children during this period.27
Despite these statistics, only 10 per cent of
Chinese children and young people consumed any snacks during the study period,
and there was little evidence then that they
consumed significant amounts of soft
drinks, although this is now changing
plant sources such as roots and tubers, cereals (grains), and
fruits.
However, this pattern is changing, with proportionally
more dietary energy available for consumption now coming
from animal sources. Since the 1960s, estimates for animal
sources for low-income countries have risen from around
160 to 340 kcal/day (670 to 1400 kJ/day). During the same
period, estimates of the energy available for consumption
from plant sources have also risen, from 1900 to 2340
kcal/day (7900 to 9800 kJ/day) (figure 1.2). There have
been similar changes in the availability of both animal and
plant sources of energy in high-income countries. However,
in these cases, the proportion of energy from animal sources
is much greater: around one third or 940 kcal/day (3900
kJ/day).81 The proportion of dietary energy available from
cereals (grains) has remained constant at around 50 per
cent, though dietary energy available from cereals (grains),
in particular rice and wheat, have decreased slightly in lowincome countries. This trend is likely to continue until the
2030s in middle- and low-income countries.81
Large variations exist across the world in the amounts of
fat available for consumption. The highest availability is in
Europe and North America; the lowest is in Africa. The quantity of available fat in diets has increased globally since the
1960s, with the exception of sub-Saharan Africa.81 These
Changes in available energy from animal
and plant food sources
Middle income
Gross domestic product per capita, 2004
International $
High income
Data from Food and Agriculture Organization1
Food energy from animal and plant food sources in selected low-,
middle-, and high-income countries, 1967–1999
Current gross domestic product per capita for selected countries in
international dollars
changes are accounted for by an increase in the availability
and consumption of plant oils in lower-income countries.82
Palm oil intake is increasing in South-East Asia, and olive oil
is now consumed widely in Europe and not just in
Mediterranean countries.
Analysis of food balance sheet data suggests that available
energy for consumption has increased steadily on a worldwide basis. Since the 1960s, this has increased globally by
approximately 450 kcal/person per day (1900 kJ/person per
day), and by more than 600 kcal/person per day (2500
kJ/person per day) in low-income countries.81 Regional differences exist. For example, there has been little change in
sub-Saharan Africa, and in Asia the amount of available energy has risen dramatically: in China by almost 1000 kcal/person per day (4200 kJ/person per day). These data need to
be interpreted with caution, as they do not relate directly to
energy consumption (box 1.1). Global average available
energy is predicted to rise from around 2800 kcal/person per
day (11700 kJ/person per day) (1997–1999 average) to
2940 (12 300 kJ) in 2015, and to 3050 (12 800 kJ) in 2030.
Again, see box 1.1.
With increasing socioeconomic status, the proportion of
energy in diets from staples such as cereals (grains) and roots
and tubers declines, whereas the proportion of energy from
fats and oil, and animal protein (including from meat, milk,
and eggs) increases. For example, in China, energy intake
from foods of animal origin has increased significantly: the
average Chinese adult now consumes more than 1300
kcal/day (5400 kJ/day) from these foods.83 In low-income
countries between the 1960s and 1990s, consumption of
meat rose by 150 per cent, and of milk and dairy products
by 60 per cent. By 2030, it is predicted that consumption of
animal products could rise by a further 44 per cent, with the
biggest contribution coming from poultry. If stocks of fish can
be maintained, fish consumption is likely to rise by 19–20
kg/person in the same period. Owing to decreases in the cost
of these foods in real terms, low-income countries have higher levels of meat and fat consumption at much lower levels
of gross domestic product (GDP) than was the case in countries that underwent socioeconomic transition in the 1960s
and 1970s. Figure 1.3 shows the GDP of selected countries.
According to food consumption surveys, only a minority of
the world's adult population consumes the commonly recommended minimum daily amount of vegetables and fruits
of 400 g/person. Low-income countries have the lowest
intakes of vegetables and fruits, and vegetables are generally more readily available than fruits.43 In India, for example,
levels of vegetable and fruit intake have remained static at
120–140 g/day. Australia, Japan, and North America have
high levels of intake, for example 300 g/day in Australia. In
Europe, average consumption is between 250 and 350 g/day
— often much higher in Mediterranean countries, for
instance 550 g/day in Spain — and Scandinavian countries
have particularly high fruit intakes.43 Countries in Europe,
Latin America, North America, and South-East Asia have seen
an increase in the availability of vegetables and fruits for con-
Measurement of food supply and consumption
The data here on energy, foods, and drinks
are taken from food balance sheets compiled by the Food and Agriculture
Organization of the United Nations. These
are statistical data on the production,
trade, and use of agricultural commodities
for all countries. Food balance sheets are
the most common and widely used data
sets for food supply estimates. A food balance sheet provides estimates of the food
available for human consumption, and an
overall picture of a country's food supply
during a specified period of time, which
can be compared between countries.
It follows that these estimates of availability are not measures of consumption.
They record information about the supply
of food (production, imports, stock
changes, and exports) and about how it is
used (as feed and seed, in processing, and
wastage, as well as food). The amounts of
foods and drinks recorded on these balance sheets are expressed 'per person' (in
kg/person per year or kcal/person per day).
The estimates in food balance sheets
that need to be treated with most caution
are those of energy. Balance sheets overestimate food consumption in high-income
countries, where substantial amounts of
food are wasted or fed to pets. They
underestimate consumption in countries
that are not dominated by urban–industrial food systems, and where many people
grow their own food, raise animals, or
gather wild food such as fungi and berries.
It follows that balance sheet data showing
increases in food energy over time tend to
reflect economic development and greater
use of money, rather than actual increases
in availability.
The accuracy of a food balance sheet
also depends on the reliability of the
underlying statistics of supply, use, and
population. Also, the data do not take into
account regional differences, so the information may not be representative of the
entire country. In countries where there is
wide variation in income and food access,
for example, the overall supply picture provided by the balance sheet is of limited use.
In such cases, food balance sheets can be
complemented with national nutrition
sumption since the 1960s. In contrast, in eastern and central Africa, availability has decreased since the mid-1980s.
Studies in children suggest that their eating patterns vary
around the world. For instance, children living in the USA
and the Philippines consume one third of their daily energy
away from home, and snacks provide one fifth of their daily
energy. In contrast, children living in Russia and China eat
very little food away from the home. Snacks provide about
16 per cent of dietary energy for Russian children, but
account for only 1 per cent in Chinese children.2
A US study showed that between 1977 and 2001, consumption of sweetened drinks increased by 135 per cent.
During the same period, milk consumption decreased by 38
per cent, resulting in an overall daily increase of 278 kcal
(1164 kJ) from drinks.31
1.2.2 Overweight and obesity
There have been rapid changes in rates of overweight and
obesity throughout the world since the 1980s, at the same
time as the urbanisation and industrialisation of middle- and
low-income countries. Such countries often experience the
dual burden of nutritional deficiencies and chronic diseases.
Also see Chapters 6 and 8.
The most recent estimates suggest that in 2002 there were
1 billion overweight or obese people worldwide, with
Chinese people accounting for approximately one fifth. The
example of China is remarkable. Historically, China, which
is classed as a lower-middle-income economy by the World
Bank, had a lean population. But the prevalence of underweight adults has decreased and the numbers of people who
surveys or household income/expenditure
surveys.
Household income/expenditure surveys,
such as the World Bank's Living Standards
Measurement Study, look at multiple
aspects of household welfare and behaviour, and collect data on the quantities of
food purchased by a representative sample
of households. These surveys provide
detailed information about foods consumed in and away from the home over a
limited time period, and can be used to
document differences in regional, geographical, or household socioeconomic
characteristics. While these surveys are
generally more useful than food balance
sheets for assessing household consumption, they are less readily available. Balance
sheets are often available for a large number of countries and for most years.
Food balance sheets, household income/
expenditure surveys, and methods of assessing individual dietary intakes (see Chapter
3) all provide information on food supply
and consumption, and they have different
purposes, uses, and limitations.
are either overweight or obese have risen considerably. In
2002, there were 184 million overweight and 31 million
obese people in China, out of a population of 1.3 billion.14
The prevalence of overweight and obesity among 7–18 year
olds increased substantially between 1985 and 2000.84
Between 1989 and 1997, one study estimated that the proportion of overweight and obese men in China rose from 6.4
to 14.5 per cent, and in women from 11.5 to 16.2 per cent.85
Another study, in nine Chinese provinces, found that
between 1989 and 2000 there was a 13.7 per cent increase
in the proportion of men, and a 7.9 per cent increase in the
proportion of women, who were overweight or obese.
During the same period, there was an average 2 per cent
decrease in the number of men and women who were classified as underweight.86
The World Health Organization MONICA Project monitored 10 million adults in 21 countries over a 10-year period in the 1980s and 1990s. During this time, the mean body
mass index (BMI) increased in most populations, with the
largest increases in regions of Australia and the USA. Over
the course of the project, the overall average BMI increased
by 1.5.87 However, average BMI decreased in Russia and
Central Europe, and in certain regions of Italy and
Switzerland. The UK has one of the highest rates of excess
weight in Europe. This has increased threefold since 1980;
in 2003, 65 per cent of men and 56 per cent of women were
overweight, with 22 per cent of men and 23 per cent of
women classified as obese.88
Historically, food insecurity, undernutrition, and underweight, and their likely contribution to infection, have been
In 2004 India had a population of over 1.1
billion, growing at a rate of about 1.2 per
cent a year; it was the next country after
China to reach the 1-billion mark.46 India
has a low-income economy, with a gross
domestic product of 1830 international
dollars per person (figure 1.3). Life
expectancy at birth is 61 years for men and
63 for women (figure 1.1).46
1.2.3 Physical activity
Changes in degrees of physical activity throughout the world
have also been rapid since the 1970s, as paid and household
Projected increases in obesity
Per cent of adults with BMI ≥30
Projections based on
adults aged 30 –100
2002 men
2002 women
the main nutrition-related public health issues in middle- and
low-income countries. This is no longer the case. Thus,
surveys of women between 1992 and 2000 found that
overweight exceeds underweight in most middle- and lowincome countries, including those in North Africa and the
Middle East, Central Asia, China, and Latin America. Indeed,
there has been a disproportionate increase in, and prevalence
of, obesity among the lowest-income groups in most countries. It is more likely that people will be overweight if they
live in urban areas compared with rural areas, and countries
with a higher GDP have a greater ratio of overweight to
underweight women.89 North Africa and the Middle East are
two areas of the world with middle- and low-income countries that are experiencing very high rates of overweight and
obesity, often higher in women than in men.82
The rise of overweight and obesity since the mid-1970s has
been much faster in lower-income countries.63 In Europe and
the USA, the prevalence has risen relatively slowly, by
0.3–0.5 per cent each year; but the figures are two- to fourfold higher in many low-income countries.90 Projections from
existing data suggest that by 2015, levels of obesity could
be as high as 50 per cent in the USA, between 30 and 40
per cent in the UK and Australia, and more than 20 per cent
in Brazil.46 See figure 1.4. It is estimated that more than 12
million adults in England will be obese by 2010, while 25
per cent of children who live in households with obese parents will become obese themselves.88
Projected increases in obesity (BMI of above 30 kg/m2) in
selected countries, 2002–2015
cent of all deaths, while infectious diseases,
maternal, perinatal, and nutritional conditions account for 32.9 per cent; 9 per cent
of deaths are due to injuries.46 The first figure gives a breakdown of deaths caused by
chronic disease.46
Common cancers in men include those of
the oral cavity and pharynx.20 Although
these cancers have declined since the late
1970s, the incidence remains high.20 Cancers
of the oesophagus and lung have also
decreased slightly in the same period.20 In
women, cancer of the cervix is the most common type, and has been since the 1970s;
breast cancer has increased steadily during
this time.20 Cancers of the oral cavity and
oesophagus have declined slightly since the
late 1970s (for age-standardised rates of
these cancers, see the second figure).20
body mass index (BMI) of 20.7, while those
aged 40–54 had an average BMI of 23.6.46
For men aged 20–70, 25.4 per cent had a
BMI of over 25.46 Women aged 20–24 had
an average BMI of 20.9, rising to an average of 24 at age 30; and women aged
30–69 also had a BMI of around 24.46 In
total, 35.8 per cent of women aged 20–70
had a BMI of over 25.46 A review from 2002
established that the prevalence of
preschool obesity was about 1 per cent, but
stunting remained a problem in over half
of all children.39 Obesity has been uncommon in India and varies with socioeconomic
status, being more common in high-income
households. In the 1970s, 2.1 per cent of
men and 2.9 per cent of women had a BMI
of 25 or more, while less than 0.5 per cent
of men and women had a BMI of 30 or
more.46 By 1998 these figures had risen: 4.4
per cent of men and 4.3 per cent of women
had a BMI of 25 or more.46 See figure 1.4
for projections of the proportions of men
and women who will have a BMI of 30 or
more in 2015.46
work has become increasingly mechanised, and vehicles are
used more often for transport. Occupational and household
physical activity has reduced dramatically in high-income
countries. Also see Chapters 5, 6 and 8.
There is as yet no globally accepted, quantified definition
of physical inactivity, or of the extent to which populations
or people should be physically active. In 2002, the WHO
recommended a minimum of 30 minutes moderate-intensity physical activity most days; it found that at least 60 per
cent of the world's population fails to achieve this level of
physical activity.91
The proportion of people employed in agriculture can
reflect the level of work-related activity undertaken in a
country, and there may be a linear relationship between the
two.91 Thus, it is likely that, compared with high-income
countries, transport-related and occupational and household
physical activity is higher in low-income countries.
Transport-related physical activity (cycling, walking) is higher in those countries with the lowest gross domestic product and low car ownership, and this differs little between
men and women.
Data on physical activity in Africa are limited. Several studies are available for South Africa, but these cannot be used
to predict or generalise about activity levels across the entire
continent. Some small regional studies have been performed,
in Ethiopia, for example, which provide useful local information, but they are not nationally representative.
Data from Europe, where recreational physical activity
accounts for a greater proportion of total activity, suggest
that approximately half of all walking and cycling trips are
less than 3 km. Therefore, almost half of European adults do
(8580 to 10 360 kJ/person per day).1
Recently, though, there have been large
increases in the consumption of animal
products, fats, and sugars. The proportion
of energy from fat has increased each year,
although within India there are differences:
for higher-income groups, 32 per cent of
energy comes from fat, compared with
17 per cent in lower-income groups.39
Since 1975 there has been a reduction in
cereal (grains) consumption, particularly
coarse grains, although this has not affected overall energy consumption. This is
probably due to large increases in intakes
of fats and animal protein, and also of milk
and milk products. In lower-income households, fat comes mainly from vegetable
foods, with very little consumption of animal fats, whereas in the highest-income
households, the majority of fat is from animal sources. India is a major producer of
vegetables and fruits, much of which are
exported.
not do enough physical activity getting from one place to
another.91 In Europe, people living in more northerly regions
such as Scandinavia have higher levels of activity than those
living further south, for example, in Mediterranean countries. Women tend to exercise less than men and this difference is greatest in southern European countries.42
A study conducted in 1953 demonstrated that more than
half of US school children failed a minimum standard of
Projected levels of inactivity in selected
regions in 2020
Insufficient
India/Bangladesh
New Zealand/Australia/Japan
Data from Bull et al93
Percentage of adults projected to have insufficient levels of
physical activity or to be inactive in 2020 in selected regions
In 2004 Japan's population was just over
128 million, with 79 per cent living in urban
areas.46 The country has a high-income
30 039 international dollars per person (figure 1.3). Life expectancy at birth is 79 years
for men and 86 for women (figure 1.1).46
maternal, perinatal, and nutritional conditions account for 10.5 per cent; 10.8 per
cent of deaths are due to injuries. The first
fitness, compared with less than 10 per cent of European
children.92 Another study in 2001 found that only 0.2 per
cent of US adults were physically active in both occupational
and transport settings, compared with 29 per cent of Chinese
adults.91 In the USA, while socioeconomic status has a large
impact on whether someone participates in recreational
physical activity, there are only small differences between
men and women, and activity levels decline with age. Similar
trends exist for men and women and for socioeconomic status in Australia.42
A number of factors will affect levels of physical activity in
future. Economic development has the effect of reducing levels of occupational, household, and transport physical activity. It reduces the amount of physical activity in the
workplace, often because of a shift from agriculture to manufacturing and service industries. Improved public transport
in middle- and low-income countries reduces transportrelated activity. Similarly, as people gain more disposable
income, they are more likely to own a car, which means that
they will make fewer journeys by bicycle or foot. Recreational
activity is the only area in which physical activity may
increase as economies develop and countries become increasingly urbanised and mechanised, although people may not
necessarily use their leisure time for active pursuits.91
Other factors constrain physical activity in cities, such as
personal safety: crime rates are often high and it may be
unsafe to walk, jog, or cycle in the streets. Furthermore, city
and town planning may not encourage people to be active
— for example, people can only walk, run, ride, and play if
Sedentary behaviour in adults in selected
countries (age 18–69)
Per cent of adults classified as sedentary
Sedentary behaviour is defined as less than 30 minutes of
moderate physical activity (equivalent to brisk walking) on fewer
than 5 days/week, or less than 20 minutes of vigorous physical
activity (equivalent to running) on fewer than 3 days/week. Also
defined in terms of 'metabolic equivalents' (METs) as achieving
less than 60 MET–hours/week of any combination of activity on
fewer than 5 days/week (also see chapter 5.2)
there are sidewalks/pavements, parks, or other areas where
they can move around freely and safely. Cultural and religious customs may also limit activity levels, particularly for
By 2020 it is predicted that more adults will be physically
figure gives a breakdown of deaths caused
by chronic diseases.46
In men, cancer of the stomach is the most
common type of cancer. This is followed by
colorectal, lung, liver, and prostate cancers,
which have increased since the 1960s.
Cancer of the oesophagus has remained
steady since the 1960s, although the incidence of cancer of the pancreas has
increased since then.20 In women, breast
cancer is the most common type and its incidence has risen since the 1970s.20 Colorectal
cancer is the next most common type, and
this has also increased. Stomach cancer incidence has decreased since the 1960s, but
the rate remains high; lung cancer has risen
steadily since the 1960s.20 The incidence of
cancer of the cervix increased during the
1960s and remained high in the 1970s, but
has since declined (for age-standardised
rates of these cancers, see the second figure). 20 However, the total numbers of new
cancer cases and cancer deaths are set to
rise because Japan has an ageing population. Cancer has been the leading cause of
death in Japan since 1981 and projections
indicate that in 2015 almost 900 000 people
will develop cancer and 450 000 will die
from cancer.47
Regional studies suggest that 68–70 per
cent of men and 70–82 per cent of women,
aged 20–70, are physically inactive.
In men there has been a steady increase
in body mass index (BMI) since the mid1970s. In 2002, 17.5 per cent of men aged
20–29 and around 30 per cent of those
aged 30–60 had a BMI of over 25. Only 7 per
cent of women aged 20–29, 19 per cent of
those aged 40–49, and 25.6 per cent of
those aged 50–59 had a BMI of over 25. See
figure 1.4 for projections of the proportions
of men and women who will have a BMI of
30 or more in 2015.
(10 780 to 11 540 kJ/person per day). Meat
consumption also increased during this
time.1 Steamed rice was the staple food
until 1950, and accounted for 80 per cent of
energy intake before 1935. Dietary intake
of cereals (grains), almost all rice, has
inactive.91 Clearly, levels of physical activity will vary in different areas and countries around the world. In Europe, for
example, the former Soviet Union states and countries in
eastern Europe are at the lower end of the estimates, with
western European countries at the higher end. Indeed, these
figures are expected to rise further in western Europe and it
is estimated that 50–60 per cent of adults will not be sufficiently physically active by 2020. Also see figure 1.5. The percentage of adults currently classified as sedentary in selected
national examples is shown in figure 1.6. Using different definitions, the amount of adults (aged over 16 years) classified as sedentary for the UK are 60 per cent of men and 66
per cent of women. For the USA 52 per cent of men and 65
per cent of women (aged over 18 years) are classified as
sedentary.46
1.2.4 Cancer
Patterns of cancer and trends, incidence, and projections vary
greatly in different parts of the world. Also see Chapter 7.
In 2002 there were more than 10 million new cases of cancer (excluding non-melanoma skin cancers) recorded worldwide, and nearly 7 million cancer deaths. By 2020 these
figures are estimated to rise to over 16 million new cases,
with 10 million deaths. There may be more than 20 million
new cases of cancer in 2030.93 Indications suggest that, at
that time, 70 per cent of cancer deaths will be in low-income
This projected increase is accounted for by a combination
of factors: the projected increase in global population; an
decreased, from 75 per cent of energy in
the 1940s to 41.3 per cent in 2000. Energy
from fat increased from 6.9 per cent in 1949
to 25 per cent in 1988, and to 26.5 per cent
in 2002. Total fat intake has increased significantly following the country's economic growth, from 15 g/person per day in the
1940s to 59 g in 1983, remaining at around
this level in 2002. The percentage of energy in diets from protein has risen from 12.4
per cent in the 1940s to 15.9 per cent in
2000. However, there has been a larger
increase in the percentage of protein from
animal sources: from 18.6 per cent in the
1940s to more than 50 per cent in 2000. In
2002, people were continuing to eat more
green and yellow vegetables, with people
over 50 tending to eat the most vegetables.
Fruit intake peaked in 1975 and has since
decreased and stabilised. In 2002, Japanese
diets did not provide the recommended
intake of calcium: although consumption of
milk and dairy products had increased, consumption of fish and shellfish had declined
slightly. Salt intake remained high, at over
12 g/person per day. 23
ageing world population; improved screening, detection, and
treatment, which increases the number of people living with
a diagnosis of cancer (see Chapter 9); the projected increases in tobacco smoking in many countries; and the increase
in the number of people with HIV/AIDS in some countries.
The global age-adjusted incidence of cancer is also likely to
increase. Also see box 1.2.
Globally, the most commonly diagnosed cancers (excluding all types of skin cancer) are those of the lung, colon and
rectum, and breast, with lung cancer being the leading cause
of cancer death.94 95 Geographical and socioeconomic differences exist for the most common cancers. In low-income
countries, the most prevalent cancers include those of which
infectious agents are a major cause, while in high-income
countries, they include hormone-related cancers. In highincome countries, and among men, prostate cancer is the
most common type, followed by cancers of the lung, stomach, and colon and rectum. In low-income countries, and
among men, lung cancer is the most common type, followed
by cancers of the oesophagus, stomach, and liver. Breast cancer is the most common type among women living in highincome countries, followed by cancers of the lung, colon and
rectum, and endometrium. Breast cancer is also the most frequent type among women living in low-income countries,
followed by cancers of the lung, stomach, and cervix.94 96
1.2.4.1 Oesophagus
Oesophageal cancer is the seventh most common type of
cancer worldwide, with more than 460 000 new cases record-
In 2001 the UK population was nearly 60
million.30 The UK is a high-income economy,
with a gross domestic product of 31 300
men and 81 for women (figure 1.1).
Chronic diseases account for 84 per cent
of all deaths, while infectious diseases,
maternal, perinatal, and nutritional conditions account for 11 per cent; 4.9 per cent
ing steadily since the 1960s, is now decreasing, and stomach cancer incidence has
declined since the 1960s.20 In women, breast
cancer is the most common type, and
although rates were fairly constant during
the 1960s and 1970s, they have risen steadily since then.20 The incidence of colorectal
cancer has remained steady since the
1960s.20 Lung cancer rose from the 1960s to
1980s, and has remained steady since
of deaths are due to injuries. The first figure below gives a breakdown of deaths
caused by chronic diseases.46
Prostate cancer is the most common cancer type in men and has increased steadily
since the 1970s.20 Lung cancer incidence
peaked in the 1960s, remained high until
the mid-1980s, and is now declining.20
Colorectal cancer has risen steadily since
1960.20 Bladder cancer, which had been ris-
Increases in BMI
ed in 2002. Because it has a poor survival rate, it is the fifth
most common
ofBMI
for ≥30
Per cent adults
25–29.9death,
Per cent
adults with BMI
000 deaths in 2002.
Incidence rates vary widely between countries. Studies
that cancer of the oesophagus is 100 times
more common in parts of China than in Europe and
North America.94 97 Other areas of high risk include southern
and eastern Africa, south-central Asia, and some countries
in South America.
Geographical variability of exposure to established car-
Measurement of cancer incidence and mortality
10 cancer registers were established in
various countries in the second half of the
0 century, descriptive studies showed
reliably for (UK)
the first time
that rates and
(England)
trends of different cancers vary, sometimes
substantially across different countries.
This variation suggested that cancer is not
from Department
of Health48
and Rosenbaum
et al49
justData
genetically
that different
cancers have different causes.
Many countries publish annual incidence
and mortality rates for cancer. The incidence rate refers to the number of new
cancer cases reported; the mortality rate
refers to the number of deaths from can-
cer. These rates are usually expressed as the
number of new cases (or deaths) each year
for every 100 000 people.
are not usually diagnosed until
they produce symptoms, so there is a period of time Women
between the first stages of cancer development and its identification. This
length of time can vary greatly, and there
are also considerable differences in survival
times and how types of cancer respond to
Many countries and international agencies track mortality statistics with causes
of death, and national or regional cancer
registries prepare cancer-incidence statistics. With types of cancer where survival is
high, cancer mortality statistics will not
reflect occurrence rates. But globally, it
is easier to obtain statistics for mortality
than for incidence, so these are often used
for comparisons between population
It can also be difficult to compare cancer incidence globally: not all countries and
regions are covered by cancer registries,
and these organisations may use different
definitions and collect different data, both
geographically and over time.
then.20 Cancer of the ovary has increased
slightly since the 1960s, and rates of cancer
of the endometrium have remained the
same since the 1960s (for age-standardised
rates of these cancers, see the second figure).20 The incidence of childhood cancer
has been rising at an average rate of 1.1
per cent each year and, between 1978 and
1997, the age-standardised incidence
increased from 120 to 141 cases/million children.22 Children in the British Isles have the
highest rates of skin cancer in Europe.11
In 2003, 64 per cent of men and 76 per
cent of women aged 16–69 were classified
as sedentary.46 A study to examine exercise
patterns in adults in 1991 and again in 1999
found that only 4 in 10 adults had managed to meet and maintain the current recommended level of activity, or to increase
their level. During the study period, the
majority either reduced their activity level
or maintained it below the recommended
level, and 15 per cent of the sample was
inactive, both in 1991 and 1999.33
In the UK, body mass index (BMI) has
risen steadily since the mid-1970s. For the
proportions of men and women in 1980
and in 2003 with a BMI of between 25 and
29.9, or of over 30, see the figure on this
page. Also see figure 1.4 for projections of
The average amount of available
food energy rose between 1964 and 2004,
Data from Inte
from around 3280
to 3480 kcal/person
per day (13 730 to
Per cent adults with BMI 25–29.9
Per cent adults with BMI ≥30
kJ/person
per day). Consumption of pasta, rice,
(grains),
yogurt, soft drinks,
savoury snacks, and
nuts has increased
since the mid-1980s.
Over the same period, intakes of fish
and fish dishes and
eggs and egg dishes
have decreased.19
Large studies suggest that fat intake
Data from Department of Health48 and Rosenbaum et al49
has decreased because people now
consume less whole
portions of vegetables and fruits. Instead,
milk, butter, and red meat, and more vegmen ate an average of 2.7 portions while
etables and fruits.35 Men surveyed between
women had 2.9.19 The survey also showed
2000 and 2001 were more likely to eat
that vegetable and fruit consumption was
foods containing fats, oils, and sugars, as
particularly low in young adults, and that
well as meat and meat products, and soft
people from low-income households were
and alcoholic drinks.
less likely to eat fruit and yogurt.19 It
In the same survey, and compared with
appears that more-educated adults put
older men and all women, young men were
dietary guidelines into practice, reducing
more likely to eat savoury snacks and soft
the amount of fat in their diets and increasdrinks, and less likely to eat eggs, fish, and
ing the amount of vegetables and fruits
fruit.19 Women ate more fruit, although
they eat.3
only 13 per cent of men and 15 per cent of
women ate the recommended five daily
cinogens can explain some of these differences. In highincome countries, alcohol and smoking tobacco are the main
carcinogenic agents, whereas chewing tobacco is more common in India. Pockets of high incidence occurring in parts
of China and in the Caspian littoral of Iran may be due to
general nutritional deficiencies. Incidence of adenocarcinoma of the lower third of the oesophagus is steadily increasing in the USA and Europe, which is likely to be linked to
an increasing incidence of acid reflux from the stomach due
to obesity.94 95 Also see chapter 7.3.
1.2.4.2 Lung
Lung (pulmonary) cancer has been the most common type
of cancer in the world since 1985, with around 1.35 million
new cases recorded in 2002. It is also the most common
cause of cancer death. In 2002, 1.2 million people died from
lung cancer.
Between 1985 and 2002, the estimated number of lung
cancer cases worldwide rose by 51 per cent, and the number of cases in middle- and low-income countries has
increased steadily over recent years. Previous estimates indicated that the majority of lung cancer cases occurred in
high-income countries (almost 70 per cent in 1980); almost
half were predicted to occur in middle- and low-income
countries in 2005.94 95 The USA and Europe have the highest numbers of lung cancer cases for both men and women,
but the incidence appears to have peaked, and may now
be declining in the USA and in parts of northern Europe. It
is, however, still increasing in southern and eastern Europe.
Men are more likely to develop lung cancer than women,
almost certainly because, on average, they smoke more than
women. Worldwide, 1 billion men and 250 million women
currently smoke tobacco. It is estimated that throughout the
20th century, 100 million people died from tobacco use.93
Also see chapter 7.4.
1.2.4.3 Stomach
Stomach (gastric) cancer is now the fourth most common
type of cancer worldwide, with around 925 000 new cases
recorded in 2002. It is the second most common cause of
death from cancer, with around 700 000 deaths annually.
Until about the mid-1980s, stomach cancer was the most
common type in the world. Since then, rates have fallen substantially in all high-income countries, and overall rates are
In 2004 Poland had a population of around
38.5 million. The country has an upper-middle-income economy, with a gross domestic
product of 12647 international dollars per
person (figure 1.3).46 Life expectancy at
birth is 71 years for men and 79 for women
(figure 1.1).46
tions account for 3.9 per cent; 7.9 per cent
Lung cancer is the most common type of
now about 15 per cent lower than in 1985.94-96
Stomach cancer is now much more common in Asia than
in the USA or Europe. Indeed, 42 per cent of cases occur in
China alone.94 97 High-risk areas are China, Japan, eastern
Europe, and Central and South America. Low-risk areas are
South-East Asia, northern and eastern Africa, the USA, and
Australia and New Zealand. In most countries, incidence has
dropped by about 15 per cent compared with 1985.
The bacterium Helicobacter pylori is an established cause
of stomach cancer. Reduction in stomach cancer rates can be
explained partly by reduced exposure to H pylori and partly by increased use of refrigeration to preserve foods.94 97 Also
see chapter 7.5.
Liver (hepatic) cancer is the sixth most common type of cancer worldwide, with around 625 000 new cases recorded in
2002. The poor prognosis makes it the third most common
cause of cancer death, with around 600 000 deaths in 2002.
In most countries, the incidence of liver cancer is stable
and there is little difference in survival rates between highand low-income countries. More than 80 per cent of cases
occur in middle- and low-income countries. Areas with a
high incidence are China (55 per cent of all new cases), subSaharan Africa, and eastern and south-eastern Asia.
Incidence is lower in high-income countries and in Latin
America, although Japan and areas of southern Europe have
intermediate incidence levels.94 96
Exposures to the hepatitis B and C viruses are known to
increase the risk of developing liver cancer; 85 per cent of
cases in low-income countries are attributed to exposures to
these two viruses. Also see chapter 7.8.
1.2.4.5 Colon and rectum
Colorectal cancer (of the colon or rectum) is the third most
common type of cancer worldwide, with just over 1 million
new cases recorded in 2002. Mortality is approximately half
that of the incidence, and nearly 530 000 deaths were
recorded in 2002, making it the fourth most common cause
of death from cancer.
There is a large geographical difference in the global distribution of colorectal cancers. Incidence varies up to 25-fold
between countries with the highest rates (the USA, Australia
and New Zealand, and in parts of Europe) and those with
the lowest rates (in Africa and Asia). Intermediate levels
occur in South America.
Incidence of colorectal cancer may be stabilising in parts
of northern and western Europe, and possibly declining
gradually in the USA. Elsewhere, however, the incidence is
increasing rapidly, particularly in Japan and in middle- and
low-income countries.94 96
As shown in 1.3, the incidence of colorectal cancer increases quickly when people migrate from low- to high-risk areas
of the world. Indeed, the incidence rate is higher in Japanese
people born in the USA than in white people born in the
USA. Also see chapter 7.9.
cancer in men and age-adjusted incidence
has remained stable since the 1970s.20 The
incidence of colorectal cancer has increased
since 1990, and both prostate and bladder
cancers have increased slightly since the
1970s.20 Stomach cancer incidence peaked in
the late 1970s and has declined steadily since.
Breast and colorectal cancers are the most
common types in women and their rates
have risen steadily since the 1970s.20 Cancer
of the cervix has remained steady since the
mid-1970s, whereas cancers of the lung,
ovary, and endometrium have increased in
this period (for age-standardised rates of
as sedentary.46
body mass index (BMI) of 23.1.46 This rose to
25.9 for men aged 30–44, while those aged
45–75 had a BMI of between 26 and 27.46
Only 2.4 per cent of men aged 15–29 had a
BMI of over 30, rising to 10.8 per cent of
those aged 30–44, and 17.5 per cent of 45–59
year olds.46 In the same year, women aged
15–29 had an average BMI of 21.2.46 Women
aged 30–44 had a BMI of 24.1, while those
aged 45–59 had a BMI of 26.7.46 Only 1.5 per
cent of women aged 15–29 had a BMI of
over 30, rising to 22.5 per cent of those aged
45–59, and 23.7 per cent of women aged
60–74.46 In a study of adults in Warsaw, the
average adult BMI remained stable between
1983 and 1993 at approximately 27.46 Overall
in 1996, 10.3 per cent of men and 12.4 per
cent of women had a BMI of 30 or more.46
See figure 1.4 for projections of the proportions of men and women who will have a
BMI of 30 or more in 2015.46
(13 850 to 14 730 kJ/person per day). The
amount of energy available from sugars
and meat increased during this period,
while the energy available from animal fats
fell substantially.1 In 1989 Poland began the
transition from a centrally planned to a
market economy. This resulted in dramatic
increases in food prices, and although the
transition gave people a better choice of
foods, there was a decline in food demand
and alterations in dietary patterns.37
1.2.4.6 Breast
Breast cancer is the most common type of cancer in women,
and the third most common cancer overall. Incidence rates
are increasing in most countries, with an estimated 1.15 million new cases recorded in 2002. Breast cancer is the sixth
most common cause of death from cancer overall. However,
it is the second most common cause of cancer death in
women, with just over 410 000 deaths recorded in 2002.
The incidence of breast cancer is highest in high-income
countries (although not in Japan) and more than half of all
cases occur in these countries. Although breast cancer has
been less common in women living in low-income countries,
age-adjusted incidence is increasing, and the rates of
increase are often greater in these countries.
Globally, estimates indicate that breast cancer incidence
has increased by 0.5 per cent annually since 1990. However,
certain cancer registries, such as those in China and other
parts of Asia, are recording annual increases in incidence of
up to 4 per cent. Rates are low in Africa, with the lowest incidence in central Africa.94 96
Migrant studies show that breast cancer rates change when
women move to a new country. See 1.3. Also see chapter
1.2.4.7 Cervix
Cancer of the cervix is the second most common type of cancer among women, and the eighth most common cancer
overall, with around 500 000 new cases recorded in 2002.
Tobacco smoking and alcoholic drink consumption are underlying factors in overall
mortality trends in eastern Europe. An
analysis of national household budget and
individual dietary surveys carried out in the
1990s found that, each day, the average
person ate around 300 g of dairy products
and the same amount of cereals (grains)
and roots and tubers, although consumption of pulses (legumes) was very low.38 A
study of students found that women ate
meat and drank beer less frequently than
men, and they ate more fruit and drank
more milk.8 Another local study, in Warsaw,
reported decreases in intakes of total energy, dietary cholesterol, and dietary animal
fats, and an increase in vegetable oil intake
between 1984 and 2001.45 Another study
found that between 1990 and 2000, the
proportion of men eating fruit each day
increased from 36 to 42 per cent. Levels of
intake were stable in women, with around
60 per cent eating fruit every day. In contrast, over the same decade, only 22–23 per
cent of men limited their fat intake,
although more women did during this period (an increase from 23 to 45 per cent).40
Cervical cancer is the seventh most common cause of death
from cancer overall, and the third most common in women,
and was responsible for nearly 275 000 deaths in 2002.
Over 80 per cent of cases occur in low-income countries.
Areas with the highest incidence rates are sub-Saharan Africa,
the Caribbean, Central and South America, and south-central and South-East Asia. Incidence rates are lowest in Europe,
the USA, Japan, China, and Australia and New Zealand.
The incidence has dropped substantially in high-income
countries following the introduction of cervical screening
programmes. The major established cause of cervical cancer
is infection with certain subtypes of human papilloma
viruses (HPV). Other cofactors (parity, contraception, HIV
infection, and smoking) can also modify the risk of this
cancer in women infected with HPV.94 96 97 Also see
chapter 7.13.
1.2.4.8 Prostate
Prostate cancer is the third most common type of cancer in
men, and the sixth most common cancer overall, with nearly 680 000 new cases recorded in 2002. The majority of cases
are diagnosed in men over the age of 65, and this cancer
accounted for just over 220 000 cancer deaths in 2002. This
made it the eighth most common cause of death from cancer overall, and the sixth most common in men.
Prostate cancer is more common in high-income countries,
but the incidence remains low in Japan. Incidence rates have
been influenced by screening programmes, which increase
In 2004 Spain had a population of over
43 million. The country has a high-income
24 325 international dollars per person (fig-
ure 1.3).46 Life expectancy at birth is 77 years
maternal, perinatal, and nutritional conditions account for 5.5 per cent; 6.9 per cent
of deaths are due to injuries. The first figure
below gives a breakdown of deaths due
diagnosis rates. This has resulted in a huge increase in the
number of recorded cases in the USA in recent years,
although the incidence in several high-income countries has
declined since the 1990s. Prostate cancer incidence is
increasing rapidly in low-income countries, particularly in
Latin American countries (such as Costa Rica, Colombia,
and Ecuador) and in China. Again, this may partly be due
to increased awareness and screening.
Mortality from prostate cancer is lower (5.8 per cent of
cancer deaths in men),94 and may give a better indication
of actual disease patterns.97 Even so, mortality is approximately 10 times more common in the USA and Europe
than in Asia. Also see chapter 7.14.
1.3 Migrant and other ecological studies
Ecological studies (also called correlation studies) examine the relationships between environmental factors and
disease outcomes, often in different countries, at an aggregate level (see chapter 3.1.2). These provided the first systematically gathered evidence suggesting that the principal
causes of cancer are environmental, and that food, nutrition, and physical activity are among these factors. Early
studies showed strong correlations among countries
between, for instance, dietary fat intake and breast cancer rates.98
While not providing strong evidence for causation, such
studies generated hypotheses for possible links between
Mortality from stomach and colorectal
cancer in European migrants to Australia
<16
>16
Data from McMichael et al102
Relative risk of death from cancer of the stomach, colon, and
rectum in European migrants to Australia (1962–1976) compared
with people born in Australia
specific nutritional factors and cancers at particular sites,
and for the general proposition that patterns of cancer might
be altered as a result of changing patterns of eating and
other ways of life. Part 2 of this Report explores the degree
to chronic diseases.46
Lung cancer is the most common cancer
type in men and incidence rates have
increased dramatically since the 1970s.20
Rates of colorectal, prostate, bladder, and
oral cancers have risen since records began
in the 1970s.20 Breast cancer is the most
common type in women and the rate has
doubled since the 1970s.20 Colorectal cancer
is the next most common type, which has
seen a steady rise during this period.20
Cancers of the endometrium and cervix
have remained steady since the 1970s, but
cancer of the ovary has risen (for age-standardised rates of these cancers, see the second figure).20
A survey in 1997 found that 76 per cent
of adults aged 16 and over did no regular
exercise during their leisure time29; 46 per
cent of adults were classified as sedentary,
with only 7 per cent of adults recording any
physical activity each week.29
Between 1994 and 1997, men aged
25–34 had an average body mass index
(BMI) of 25, while those aged 35–44 had a
Cancer among female Iranian migrants
to British Columbia, Canada
BMI of 26, and 45–75 year olds had a BMI
of 27.46 In total, 35 per cent of men aged
25–64 had a BMI of over 27, and 12.2 per
cent had a BMI of over 30.46 Women aged
25–34 had an average BMI of 23, while
those aged 35–44 had a BMI of 25, and
45–74 year olds had a BMI of between 27
and 28.46 Overall, 25.7 per cent of women
aged 25–64 had a BMI of over 27, and 12.1
per cent had a BMI of over 30.46
Over the period 1977–1993, the proportion of people with energy-intensive jobs
halved. In children aged 6–7, there has
been a marked increase in obesity and overweight, higher even than in US children of
the same age. Obesity in adolescents is also
among the highest in the world.29 Between
1990 and 2000, 45 per cent of men and 32.2
per cent of women had a BMI of 25 or
more, and 13.4 per cent of men and 15.8
more. See figure 1.4 for projections of the
proportions of men and women who will
have a BMI of 30 or more in 2015.46
Age-standardised incidence in women per 100 000
migrants to
(11 330 to 14 590 kJ/person per day), due
largely to an increase in the availability of
sugars and meat.1 The Mediterranean-style
diet is often seen as the healthiest in
Europe, but Spanish diets have recently
shifted towards being high in fat and dairy
products, with only moderate amounts of
vegetables. Dairy and fruit intakes are the
highest in Europe, but so is the proportion
of energy in diets from fat.29 Between 1964
and 1990, consumption of plant-based
foods decreased from 1289 to 995 g/person
per day. In the same period, intakes of cereals (grains), pulses (legumes), and potatoes
all halved. While consumption of other vegetables remained stable, fruit intake doubled to 327 g/person per day. Consumption
of animal products increased from 407 to
743 g/person per day due to a large
increase in the amounts of meat, poultry,
milk, and dairy products in people's
diets, although intakes of animal fats
decreased.29
Incidence of colorectal cancer in Asian
migrants to USA and their descendants
Data from Yavari et al104
Age-standardised incidence of breast and colorectal cancer is
increased in Asian migrants to Canada compared with source
Incidence rate per 100 000 people
Data from Flood et al106
Age-standardised incidence of colorectal cancer is increased in the
descendants of Japanese migrants to the USA
to which such hypotheses are upheld or refuted by the totality of the relevant published literature, including more robust
observational and also experimental types of study.
The most compelling evidence, suggesting that the main
causes of cancers of most sites are environmental (due to factors that people are exposed to) rather than genetically
inherited comes from studies of migrant populations.
There are many migrant populations. Examples include
people who have migrated from eastern Asia to the
Americas; from the Indian subcontinent to Africa and the
UK; from Europe to Australia; and from Africa to the
Caribbean, and then to the UK. All of these population movements are accompanied by marked changes in patterns of
diet, physical activity, and disease.
Migrations from Japan to the USA, from the Caribbean to
the UK, and from European countries to Australia have been
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