<title>Introduction</title> <p>Inaccurate recognition of weight status is a threat to healthy weight control. Until
the mid-1990s, the emphasis was on young women’s tendency to identify themselves as
overweight despite a healthy body size,##REF##3245208##1##
##REF##2376839##2##
##REF##2388787##3## and concern focused primarily on the risks
of eating disorders. With rates of anorexia remaining stable##REF##15684236##4## but obesity rates rising inexorably,##UREF##0##5##
##UREF##1##6## attention has now turned to awareness of
weight status among those who are overweight or obese. A considerable proportion of
overweight adults—men in particular—do not recognise that their body weight is too
high,##REF##15567804##7##
##REF##12119582##8##
##REF##10454108##9## and many parents fail to recognise that
their children are overweight.##REF##15768040##10##
##REF##16510647##11##
##REF##17228044##12##</p> <p>The clinical categories “overweight” and “obese,” defined by BMI (body mass index)
thresholds of over 25 and over 30, respectively, are used universally by health
professionals to evaluate risks associated with excess body weight. Lay definitions
of these terms, however, might differ from those of clinicians, and such
discrepancies can present a barrier to communication between the health profession
and the public. The public’s weight perceptions are probably less rigidly defined
and influenced by perceptions of acceptable weight related to specific cultural and
social groups.##REF##12006633##13##
##REF##16151414##14##
##REF##15099168##15##</p> <p>Changes in the social environment over recent years could have affected weight
perceptions in several ways. Increased attention to the “obesity epidemic” and
publicity channelled through the media and health professionals to encourage
appropriate action for weight control##UREF##2##16##
##UREF##3##17## might be expected to promote recognition
of overweight. There has also been an emphasis on positive body images for young
women, which should have reduced inaccurate perceptions of overweight among normal
weight women. On this basis, weight recognition should have become more
accurate.</p> <p>Media reports about body weight, however, often use images of severe obesity, which
could give the impression that extremely high weights are required to meet medical
criteria for overweight. In addition, increases in adiposity in the population might
have “normalised” overweight, leading to increased acceptance of body fat and
reduced recognition of excess weight. The social comparison effects might also mean
that fewer normal weight individuals incorrectly perceive themselves to be
overweight. On this basis, recognition of overweight might be expected to be worse
in overweight and obese individuals.</p> <p>Accuracy in self diagnosing overweight can be approached with the diagnostic concepts
of sensitivity and specificity.##REF##8019315##18##
Sensitivity is the proportion of truly overweight people who identify themselves as
such, while specificity is the proportion of people who are not overweight who
identify themselves correctly as not overweight. If the combined emphasis on public
awareness of the risks of obesity and promotion of a healthy body image in young
women has been successful, then both sensitivity and specificity of self diagnosed
overweight should have increased. On the other hand, if social comparison processes
have led to normalisation of overweight, any increase in specificity might have been
accompanied by a decrease in sensitivity.</p> <p>We investigated changes in public perception of overweight over an eight year period,
and assessed effects on the self diagnostic abilities of overweight and normal
weight British adults.</p>
<title>Methods</title> <title>Study design and participants</title> <p>We compared self reported weights and perceptions of weight from two population
based surveys carried out eight years apart. The first survey was carried out
through the Office for National Statistics (ONS) omnibus survey of March 1999. A
probability sample of women and men was selected, using random sampling of
addresses on the postcode address file of private households in Great Britain.
Further details of the methods can be obtained at <ext-link ext-link-type="uri" xlink:href="www.ons.gov.uk/about/who-we-are/our-services/omnibus-survey">www.ons.gov.uk/about/who-we-are/our-services/omnibus-survey</ext-link>.
Within each household, one adult was randomly selected for interview. These data
have been previously published.##REF##12119582##8##</p> <p>The second survey was a face to face omnibus survey conducted in May 2007 by the
British Market Research Bureau (BMRB) using a two stage random location sampling
method. Enumeration districts defined by the 2001 census (excluding Northern
Ireland and the Western Isles) were selected at random, and 83 sample areas were
used. Sample units, composed of around 300 households, were stratified by
demographic characteristics and region and randomly selected, with probability
of selection proportional to the population. The use of stratifiers ensures all
types of area are fully represented. Further information is available from
<ext-link ext-link-type="uri" xlink:href="www.bmrb.co.uk/?id=755">www.bmrb.co.uk/?id=755</ext-link>. In both surveys the interviews were
undertaken in the home with only one interview per household. Both produced
samples that closely resembled the demography of the population of Great
Britain.</p> <title>Measures</title> <p><italic>Demographic variables</italic>—Demographic variables included in the
present analyses were age, sex, and age on leaving education.</p> <p><italic>Anthropometric data</italic>—Weight and height were self reported in
whichever metric the individual preferred. Use of self reported anthropometric
data means that height is likely to be overestimated and weight
underestimated,##UREF##4##19##
##REF##7667492##20## and therefore average BMI and the
proportion of the population who are overweight or obese will be underestimated
in both samples. Participants were divided into weight groups using BMI cut offs
of &lt;18.5 (underweight), &gt;25 (overweight), and &gt;30 (obese).</p> <p><italic>Perceived weight</italic>—Participants were asked to select a descriptor
for their own body weight from the following list: very underweight,
underweight, about right, overweight, and very overweight. The 2007 survey also
included the category “obese.” For most of the analyses reported here, we
dichotomised the data into a “perceived overweight” group, comprising the top
two (three in 2007) categories, versus the rest.</p> <title>Data analysis</title> <p>Data were provided with weightings for household size and analyses were carried
out on weighted and unweighted data, but as there were no substantial
differences in results, we present the unweighted results. Analyses were carried
out in SPSS version 14 and Stata version 9.2. We used <italic>t</italic> tests
and χ<sup>2</sup> analyses for comparisons between the two surveys and further
examined perceptions of overweight using log binomial regression, with
dichotomised perceived overweight as the dependent variable. Independent
variables were age, age on leaving education, sex, survey year, and weight
group. We calculated specificity and sensitivity of perceptions of overweight
and 95% confidence intervals using the efficient score method (corrected for
continuity), as described by Newcombe.##REF##9595616##21##</p>
<title>Results</title> <title>Sample characteristics, 1999 and 2007</title> <p>In 1999, 1894 interviews were carried out, comprising 882 men and 1012 women.
Adequate weight and height data were collected from 853 men and 944 women. The
2007 sample of 1998 participants comprised 895 men and 1103 women, of whom 847
men and 989 women provided adequate data on height and weight.</p> <p>There was no significant difference in sex balance between the two time points:
53% women in 1999 and 54% women in 2007. There was no overall difference in age,
but women in the 1999 sample were slightly older than those in the 2007 sample
(<italic>t</italic>=3.05, P&lt;0.01) (table 1). There was a significant difference in age of completing
education (<italic>t</italic>=2.61, P&lt;0.01) with participants in the 2007
sample being slightly older. This was probably because of increases in the legal
school leaving age.</p> <title>Weight and perceptions of overweight</title> <p>Height did not differ significantly between the samples, but both weight and BMI
were higher in 2007 (<italic>t</italic>=6.09, P&lt;0.001, and
<italic>t</italic>=7.77, P&lt;0.001, respectively). The proportion of
respondents whose BMI placed them in the obese category had nearly doubled, from
11% to 19% (table 2).</p> <p>In contrast with the upward trends in overweight and obesity, trends in perceived
overweight were downward. In 1999, 43% of the population had a BMI that put them
in the overweight or obese range, of whom 81% perceived themselves to be
overweight or very overweight. In 2007, 53% of the population had a BMI in the
overweight or obese range, of whom only 75% reported themselves to be
overweight, very overweight, or obese.</p> <p>We used log binomial regression to establish the significance of differences in
weight perceptions between 1999 and 2007, controlling for differences in
demographic composition of the samples (table 3). Age on leaving education did not achieve significance in the
model. All other independent variables were significant predictors of perceived
overweight.</p> <p>The effect of survey year on perception of overweight was highly significant,
with participants in 2007 less likely to perceive themselves as overweight,
given their weight group, sex, age, and education. Figure 1 shows how perceptions of overweight changed across the BMI
spectrum and between the two surveys.</p> <p>Weight group was strongly associated with perceived overweight. Just one (&lt;1%)
of the underweight participants and 19% of normal weight participants perceived
themselves to be overweight, compared with 70% of those who were overweight and
94% of those who were obese.</p> <title>Sensitivity and specificity of self perception of overweight </title> <p>We examined sensitivity and specificity of weight perceptions, together with 95%
confidence intervals, for the two samples (table 4). In the sample as a whole, sensitivity of recognition of
overweight decreased between 1999 and 2007, alongside an increase in
specificity. When we analysed data for men and women separately, we found a
similar pattern of results for both groups, but results for the men did not
reach significance. Figure 2 shows changes in sensitivity and specificity.</p>
<title>Discussion</title> <p>Despite the topic of weight scarcely being out of the news, these data from two
population surveys show that fewer overweight and obese people defined themselves as
overweight in 2007 than in 1999. The changes indicate a marked decline in
sensitivity with respect to individuals’ detection of their own overweight. There
was a concurrent improvement in specificity, with fewer people of normal or low
weight believing themselves to be overweight. These effects were strongest in women,
marginally failing to reach significance in men.</p> <title>Interpretation</title> <p>A decline in sensitivity of recognition of overweight has important implications
for the targeting of public health messages, which are unlikely to reach
marginally overweight individuals if they fail to identify themselves as
targets. These are the very people for whom lifestyle changes might have
beneficial effects, potentially preventing weight related comorbidities. Recent
research in primary care has suggested that communication between primary care
practitioners and overweight patients is inadequate,##REF##17828672##22## and our results show on a national level that the
attempts of health professionals to ensure that overweight individuals are aware
of their weight status have been largely unsuccessful.</p> <p>Increased attention to the health risks of excess weight might have left
individuals more reluctant to identify themselves with labels such as
“overweight” or “obese.” Certainly, there is evidence that some overweight
individuals resist identifying with terminology that they perceive as
stigmatising, preferring to adopt euphemistic identifiers for overweight such as
“chubby” or “big boned.”##REF##18254835##23## This raises
the question of how health professionals can best establish a vocabulary for the
discussion of body weight that is precise enough and neither minimises the risks
associated with excess weight nor provokes disengagement on the part of the
patient.</p> <p>One advantage of the shifting standard for overweight is that slightly fewer
normal weight women think they are overweight. This has implications for
practitioners and policy makers working in the field of eating disorders as well
as obesity prevention. Concern has often been expressed that women are
unnecessarily worried about their weight.##REF##8363189##24##
##REF##1860968##25## Our data suggest that inappropriate
perceptions of overweight are declining among women in the normal weight
range.</p> <title>Explaining changing weight perceptions</title> <p>Various factors might have contributed to the declining ability of overweight
individuals to recognise that their weight is too high. Social comparison is
likely to play an important role in the development of societal weight norms,
resulting in the threshold for perceived overweight rising in line with
increasing weight in the population. International data have suggested that
perceptions of overweight are related to levels of overweight in the local
population, supporting the social norm hypothesis.##REF##16151414##14## In the context of changing population weight, a
greater understanding of the role of social comparison in weight perception
would be beneficial.</p> <p>Another possible explanation relates to the type of images that often accompany
media and health information. Photographic illustrations often depict severely
obese people, untypical of the overweight population. This might act as false
reassurance for those who are “merely” overweight, implicitly reinforcing a
perception that messages about healthy eating and exercise are not aimed at
them.</p> <title>Strengths and weaknesses of the study</title> <p>While the demographic composition of the two samples was similar, there were
small differences between years. Women in the 2007 survey were slightly older,
and both men and women report more years of schooling. Inclusion of these as
covariates in the analyses, however, did not change the findings. Data
collection methods were not identical between the two surveys. In 2007, the
option for university researchers to include items in the ONS Omnibus survey was
not available, and therefore we used the BMRB Omnibus survey. Both samples
produced were representative of the population and in both cases a computer
assisted face to face survey was used, and therefore any social desirability
bias is likely to affect both sets of data in a similar way.</p> <p>A drawback of the methods is the use of self reported heights and weights. The
use of self reports facilitates large scale data collection but is always a
source of inaccuracy, resulting in underestimates of weight (particularly in
women) and overestimates of height (particularly in men).##UREF##4##19##
##REF##7667492##20## It is therefore likely that BMI and
the prevalence of overweight are underestimated in both samples. There is no
reason to expect that this accounts for the difference in weight perceptions as
the same methods were used in both surveys and any inaccuracy is likely to be
similar across both phases of data collection. In the absence of a study
comparing self reported and measured weights and height over time, however, it
is not possible to be certain that there has been no change in estimations of
weight and height.</p>
<p><bold>Objectives</bold> To examine changes in public perceptions of overweight in
Great Britain over an eight year period.</p> <p><bold>Design</bold> Comparison of data on self perceived weight from population
surveys in 1999 and 2007.</p> <p><bold>Setting</bold> Household surveys of two representative samples in Great
Britain.</p> <p><bold>Participants</bold> 853 men and 944 women in 1999, and 847 men and 989
women in 2007.</p> <p><bold>Main outcome measures</bold> Participants were asked to report their weight
and height and classify their body size on a scale from “very underweight” to
“obese.”</p> <p><bold>Results</bold> Self reported weights increased dramatically over time, but
the weight at which people perceived themselves to be overweight also rose
significantly. In 1999, 81% of overweight participants correctly identified
themselves as overweight compared with 75% in 2007, demonstrating a decrease in
sensitivity in the self diagnosis of overweight.</p> <p><bold>Conclusions</bold> Despite media and health campaigns aiming to raise
awareness of healthy weight, increasing numbers of overweight people fail to
recognise that their weight is a cause for concern. This makes it less likely
that they will see calls for weight control as personally relevant.</p>
<p><bold>Cite this as:</bold>
<italic>BMJ</italic> 2008;337:a494</p>
<fig id="fig1" position="float"><caption><p><bold>Fig 1</bold> Proportion of men and women who perceived themselves
overweight. All BMI values rounded down</p></caption></fig> <fig id="fig2" position="float"><caption><p><bold>Fig 2</bold> Sensitivity and specificity of perception of
overweight. Sensitivity denotes proportion of overweight participants
who correctly identify themselves as overweight. Specificity denotes
proportion of normal and underweight participants who correctly identify
that they are not overweight</p></caption></fig>
<table-wrap id="tbl1" position="float"><label>Table 1</label><caption><p> Participants in survey samples, 1999 and 2007. Figures are means
(SD)</p></caption><table frame="hsides" rules="groups"><thead><tr><th colspan="1" rowspan="2" align="left" valign="bottom"/><th colspan="2" rowspan="1" align="center" valign="bottom">All
participants</th><th colspan="1" rowspan="2" align="center" valign="bottom"/><th colspan="2" rowspan="1" align="center" valign="bottom">Women</th><th colspan="1" rowspan="2" align="center" valign="bottom"/><th colspan="2" rowspan="1" align="center" valign="bottom">Men</th></tr><tr><th colspan="1" rowspan="1" align="center" valign="bottom">1999
(n=1797)</th><th colspan="1" rowspan="1" align="center" valign="bottom">2007
(n=1836)</th><th colspan="1" rowspan="1" align="center" valign="bottom">1999
(n=944)</th><th colspan="1" rowspan="1" align="center" valign="bottom">2007
(n=989)</th><th colspan="1" rowspan="1" align="center" valign="bottom">1999
(n=853)</th><th colspan="1" rowspan="1" align="center" valign="bottom">2007
(n=847)</th></tr></thead><tbody><tr><td colspan="1" rowspan="1" align="left" valign="top">Age</td><td colspan="1" rowspan="1" align="center" valign="top">48.25
(18.36)</td><td colspan="1" rowspan="1" align="center" valign="top">47.61
(19.04)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">49.32
(18.75)</td><td colspan="1" rowspan="1" align="center" valign="top">46.74
(18.53)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">47.06
(17.86)</td><td colspan="1" rowspan="1" align="center" valign="top">48.64
(19.57)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Age on leaving
education</td><td colspan="1" rowspan="1" align="center" valign="top">17.07
(2.83)</td><td colspan="1" rowspan="1" align="center" valign="top">17.32
(2.96)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">17.03
(2.76)</td><td colspan="1" rowspan="1" align="center" valign="top">17.28
(2.89)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">17.11
(2.90)</td><td colspan="1" rowspan="1" align="center" valign="top">17.38
(3.03)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Height
(cm)</td><td colspan="1" rowspan="1" align="center" valign="top">169.15
(10.18)</td><td colspan="1" rowspan="1" align="center" valign="top">168.89
(10.38)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">162.69
(7.32)</td><td colspan="1" rowspan="1" align="center" valign="top">162.74
(7.72)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">176.29
(7.87)</td><td colspan="1" rowspan="1" align="center" valign="top">176.07
(8.27)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Weight
(kg)</td><td colspan="1" rowspan="1" align="center" valign="top">71.91
(14.89)</td><td colspan="1" rowspan="1" align="center" valign="top">74.91
(16.19)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">65.19
(13.20)</td><td colspan="1" rowspan="1" align="center" valign="top">68.31
(14.44)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">78.55
(13.42)</td><td colspan="1" rowspan="1" align="center" valign="top">81.55
(15.12)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">BMI</td><td colspan="1" rowspan="1" align="center" valign="top">24.91
(4.48)</td><td colspan="1" rowspan="1" align="center" valign="top">26.17
(5.22)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">24.53
(4.81)</td><td colspan="1" rowspan="1" align="center" valign="top">26.05
(5.63)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">25.33
(4.03)</td><td colspan="1" rowspan="1" align="center" valign="top">26.30
(4.71)</td></tr></tbody></table></table-wrap> <table-wrap id="tbl2" position="float"><label>Table 2</label><caption><p> Self reported and perceived weight 1999 and 2007. Figures are
percentages (numbers)</p></caption><table frame="hsides" rules="groups"><thead><tr><th colspan="1" rowspan="2" align="left" valign="bottom"/><th colspan="2" rowspan="1" align="center" valign="bottom">All
participants</th><th colspan="1" rowspan="2" align="center" valign="bottom"/><th colspan="2" rowspan="1" align="center" valign="bottom">Women</th><th colspan="1" rowspan="2" align="center" valign="bottom"/><th colspan="2" rowspan="1" align="center" valign="bottom">Men</th></tr><tr><th colspan="1" rowspan="1" align="center" valign="bottom">1999</th><th colspan="1" rowspan="1" align="center" valign="bottom">2007</th><th colspan="1" rowspan="1" align="center" valign="bottom">1999</th><th colspan="1" rowspan="1" align="center" valign="bottom">2007</th><th colspan="1" rowspan="1" align="center" valign="bottom">1999</th><th colspan="1" rowspan="1" align="center" valign="bottom">2007</th></tr></thead><tbody><tr><td colspan="9" rowspan="1" align="left" valign="top">Reported
weight status*:</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Underweight</td><td colspan="1" rowspan="1" align="center" valign="top">2.8
(50)</td><td colspan="1" rowspan="1" align="center" valign="top">2.9
(53)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">3.9
(37)</td><td colspan="1" rowspan="1" align="center" valign="top">3.3
(33)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">1.5
(13)</td><td colspan="1" rowspan="1" align="center" valign="top">2.4
(20)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Normal
weight</td><td colspan="1" rowspan="1" align="center" valign="top">54.5
(979)</td><td colspan="1" rowspan="1" align="center" valign="top">44.2
(812)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">59.6
(563)</td><td colspan="1" rowspan="1" align="center" valign="top">47.2
(467)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">48.8
(416)</td><td colspan="1" rowspan="1" align="center" valign="top">40.7
(345)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Overweight</td><td colspan="1" rowspan="1" align="center" valign="top">31.9
(574)</td><td colspan="1" rowspan="1" align="center" valign="top">34.2
(628)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">24.8
(234)</td><td colspan="1" rowspan="1" align="center" valign="top">30.9
(306)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">39.9
(340)</td><td colspan="1" rowspan="1" align="center" valign="top">38.0
(322)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Obese</td><td colspan="1" rowspan="1" align="center" valign="top">10.8
(194)</td><td colspan="1" rowspan="1" align="center" valign="top">18.7
(343)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">11.7
(110)</td><td colspan="1" rowspan="1" align="center" valign="top">18.5
(183)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">9.8
(84)</td><td colspan="1" rowspan="1" align="center" valign="top">18.9
(160)</td></tr><tr><td colspan="9" rowspan="1" align="left" valign="top">Perceived
weight:</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Underweight†</td><td colspan="1" rowspan="1" align="center" valign="top">7.6
(136)</td><td colspan="1" rowspan="1" align="center" valign="top">5.1
(94)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">6.9
(65)</td><td colspan="1" rowspan="1" align="center" valign="top">3.3
(33)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">8.3
(71)</td><td colspan="1" rowspan="1" align="center" valign="top">7.2
(61)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> About right
weight</td><td colspan="1" rowspan="1" align="center" valign="top">45.7
(821)</td><td colspan="1" rowspan="1" align="center" valign="top">47.3
(869)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">43.9
(414)</td><td colspan="1" rowspan="1" align="center" valign="top">44.5
(440)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">47.7
(407)</td><td colspan="1" rowspan="1" align="center" valign="top">50.6
(429)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Somewhat
overweight</td><td colspan="1" rowspan="1" align="center" valign="top">39.3
(706)</td><td colspan="1" rowspan="1" align="center" valign="top">38.5
(706)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">39.6
(374)</td><td colspan="1" rowspan="1" align="center" valign="top">40.3
(399)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">38.9
(332)</td><td colspan="1" rowspan="1" align="center" valign="top">36.2
(307)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Very
overweight</td><td colspan="1" rowspan="1" align="center" valign="top">7.5
(134)</td><td colspan="1" rowspan="1" align="center" valign="top">7.3
(134)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">9.6
(91)</td><td colspan="1" rowspan="1" align="center" valign="top">9.1
(90)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">5.0
(43)</td><td colspan="1" rowspan="1" align="center" valign="top">5.2
(44)</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Obese</td><td colspan="1" rowspan="1" align="center" valign="top">NA</td><td colspan="1" rowspan="1" align="center" valign="top">1.8
(33)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">NA</td><td colspan="1" rowspan="1" align="center" valign="top">2.7
(27)</td><td colspan="1" rowspan="1" align="center" valign="top"/><td colspan="1" rowspan="1" align="center" valign="top">NA</td><td colspan="1" rowspan="1" align="center" valign="top">0.7 (6)</td></tr></tbody></table></table-wrap> <table-wrap id="tbl3" position="float"><label>Table 3</label><caption><p> Log binomial regression: variables associated with perceived
overweight</p></caption><table frame="hsides" rules="groups"><thead><tr><th colspan="1" rowspan="1" align="left" valign="bottom"/><th colspan="1" rowspan="1" align="center" valign="bottom">Relative
risk of perceived overweight (95% CI)</th><th colspan="1" rowspan="1" align="center" valign="bottom">z
score</th><th colspan="1" rowspan="1" align="center" valign="bottom">P
value</th></tr></thead><tbody><tr><td colspan="1" rowspan="1" align="left" valign="top">Age</td><td colspan="1" rowspan="1" align="center" valign="top">0.998 (0.996
to 0.999)</td><td colspan="1" rowspan="1" align="center" valign="top">−2.54</td><td colspan="1" rowspan="1" align="center" valign="top">0.011</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Age on leaving
education</td><td colspan="1" rowspan="1" align="center" valign="top">0.997 (0.994
to 1.000)</td><td colspan="1" rowspan="1" align="center" valign="top">−1.92</td><td colspan="1" rowspan="1" align="center" valign="top">0.055</td></tr><tr><td colspan="4" rowspan="1" align="left" valign="top">Weight group
(BMI):</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Underweight
(&lt;18.5)</td><td colspan="1" rowspan="1" align="center" valign="top">0.05 (0.01
to 0.34)</td><td colspan="1" rowspan="1" align="center" valign="top">−3.03</td><td colspan="1" rowspan="1" align="center" valign="top">0.002</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Normal weight
(18.5-&lt;25)</td><td colspan="1" rowspan="1" align="center" valign="top">1.00</td><td colspan="1" rowspan="1" align="center" valign="top">—</td><td colspan="1" rowspan="1" align="center" valign="top">—</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Overweight
(25-&lt;30)</td><td colspan="1" rowspan="1" align="center" valign="top">3.69 (3.35
to 4.07)</td><td colspan="1" rowspan="1" align="center" valign="top">26.26</td><td colspan="1" rowspan="1" align="center" valign="top">&lt;0.001</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Obese
(&gt;30)</td><td colspan="1" rowspan="1" align="center" valign="top">4.82 (4.39
to 5.31)</td><td colspan="1" rowspan="1" align="center" valign="top">32.29</td><td colspan="1" rowspan="1" align="center" valign="top">&lt;0.001</td></tr><tr><td colspan="4" rowspan="1" align="left" valign="top">Sex:</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Men</td><td colspan="1" rowspan="1" align="center" valign="top">1.00</td><td colspan="1" rowspan="1" align="center" valign="top">—</td><td colspan="1" rowspan="1" align="center" valign="top">—</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> Women</td><td colspan="1" rowspan="1" align="center" valign="top">1.33 (1.26
to 1.40)</td><td colspan="1" rowspan="1" align="center" valign="top">10.20</td><td colspan="1" rowspan="1" align="center" valign="top">&lt;0.001</td></tr><tr><td colspan="4" rowspan="1" align="left" valign="top">Survey
year:</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> 1999</td><td colspan="1" rowspan="1" align="center" valign="top">1.00</td><td colspan="1" rowspan="1" align="center" valign="top">—</td><td colspan="1" rowspan="1" align="center" valign="top">—</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top"> 2000</td><td colspan="1" rowspan="1" align="center" valign="top">0.87 (0.83
to 0.92)</td><td colspan="1" rowspan="1" align="center" valign="top">−4.86</td><td colspan="1" rowspan="1" align="center" valign="top">&lt;0.001</td></tr></tbody></table></table-wrap> <table-wrap id="tbl4" position="float"><label>Table 4</label><caption><p> Prevalence of overweight and sensitivity and specificity of recognition
of overweight in men and women, 1999 and 2007</p></caption><table frame="hsides" rules="groups"><thead><tr><th colspan="1" rowspan="2" align="left" valign="bottom"/><th colspan="2" rowspan="1" align="center" valign="bottom">Prevalence/sensitivity/specificity (95% CI), No in group</th><th colspan="1" rowspan="2" align="center" valign="bottom">χ<sup>2</sup>, P value</th></tr><tr><th colspan="1" rowspan="1" align="center" valign="bottom">1999 </th><th colspan="1" rowspan="1" align="center" valign="bottom">2007
</th></tr></thead><tbody><tr><td colspan="4" rowspan="1" align="left" valign="bottom" content-type="TableSubHead"><bold>Prevalence</bold></td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Men</td><td colspan="1" rowspan="1" align="center" valign="top">0.50 (0.46
to 0.53), 903</td><td colspan="1" rowspan="1" align="center" valign="top">0.57 (0.54
to 0.60), 916</td><td colspan="1" rowspan="1" align="center" valign="top">7.72,
P=0.005</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Women</td><td colspan="1" rowspan="1" align="center" valign="top">0.36 (0.33
to 0.40), 895</td><td colspan="1" rowspan="1" align="center" valign="top">0.49 (0.46
to 0.53), 921</td><td colspan="1" rowspan="1" align="center" valign="top">25.65,
P&lt;0.001</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">All</td><td colspan="1" rowspan="1" align="center" valign="top">0.43 (0.40
to 0.45), 1798</td><td colspan="1" rowspan="1" align="center" valign="top">0.53 (0.51
to 0.55), 1837</td><td colspan="1" rowspan="1" align="center" valign="top">30.15,
P&lt;0.001</td></tr><tr><td colspan="4" rowspan="1" align="left" valign="bottom" content-type="TableSubHead"><bold>Sensitivity</bold></td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Men</td><td colspan="1" rowspan="1" align="center" valign="top">0.75 (0.70
to 0.79), 446</td><td colspan="1" rowspan="1" align="center" valign="top">0.67 (0.62
to 0.71), 512</td><td colspan="1" rowspan="1" align="center" valign="top">3.09,
P=0.079</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Women</td><td colspan="1" rowspan="1" align="center" valign="top">0.90 (0.86
to 0.93), 331</td><td colspan="1" rowspan="1" align="center" valign="top">0.83 (0.80
to 0.87), 449</td><td colspan="1" rowspan="1" align="center" valign="top">10.40,
P=0.001</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">All</td><td colspan="1" rowspan="1" align="center" valign="top">0.81 (0.78
to 0.84), 777</td><td colspan="1" rowspan="1" align="center" valign="top">0.75 (0.72
to 0.78), 961</td><td colspan="1" rowspan="1" align="center" valign="top">8.02,
P=0.005</td></tr><tr><td colspan="4" rowspan="1" align="left" valign="bottom" content-type="TableSubHead"><bold>Specificity</bold></td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Men</td><td colspan="1" rowspan="1" align="center" valign="top">0.86 (0.83
to 0.89), 457</td><td colspan="1" rowspan="1" align="center" valign="top">0.90 (0.87
to 0.93), 404</td><td colspan="1" rowspan="1" align="center" valign="top">3.51,
P=0.061</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">Women</td><td colspan="1" rowspan="1" align="center" valign="top">0.74 (0.70
to 0.77), 564</td><td colspan="1" rowspan="1" align="center" valign="top">0.78 (0.75
to 0.82), 472</td><td colspan="1" rowspan="1" align="center" valign="top">6.47,
P=0.011</td></tr><tr><td colspan="1" rowspan="1" align="left" valign="top">All</td><td colspan="1" rowspan="1" align="center" valign="top">0.79 (0.76
to 0.81), 1012</td><td colspan="1" rowspan="1" align="center" valign="top">0.83 (0.81
to 0.86), 876</td><td colspan="1" rowspan="1" align="center" valign="top">9.87,
P=0.002</td></tr></tbody></table></table-wrap>
<boxed-text position="float" content-type="style3"><sec><title>What is already known on this topic</title><list list-type="simple"><list-item><p>Perceptions of overweight in the population do not correspond
well to the definitions used by health professionals</p></list-item><list-item><p>Many overweight and obese individuals fail to recognise that
their weight is too high</p></list-item></list></sec><sec><title>What this study adds</title><list list-type="simple"><list-item><p>As the proportion of overweight people in Great Britain has
increased, the ability of overweight individuals to “self
diagnose” their weight problem has declined</p></list-item></list></sec></boxed-text>
<table-wrap-foot><p>NA=not applicable (not a category in 1999 survey).</p><p>*Mutually exclusive categories.</p><p>†Includes very underweight.</p></table-wrap-foot> <fn-group><fn><p>Data collection was carried out by the Office for National Statistics (ONS)
and the British Market Research Bureau (BMRB).</p></fn><fn fn-type="participating-researchers"><p>Contributors: JW was the lead researcher and conceived the project. She led
the study design and development of materials in both 1999 and 2007 and
participated in data analysis and interpretation for both surveys. She made
a substantial contribution to content of the paper and is guarantor. FJ
participated in the study design and development of materials for the 1999
survey, carried out statistical analyses of data from both surveys, and
drafted the paper. LC designed materials and liaised with the data
collection bodies in 2007. She also made revisions to the paper. HC was
involved in the development of survey materials in 2007 and made revisions
to the paper. All authors approved the final version of the paper for
publication.</p></fn><fn fn-type="financial-disclosure"><p>Funding: Cancer Research UK and the Economic and Social Research Council.</p></fn><fn fn-type="conflict"><p>Competing interests: None declared.</p></fn><fn><p>Ethical approval: Not required.</p></fn><fn><p>Provenance and peer review: Not commissioned; externally peer reviewed.</p></fn></fn-group>
<graphic xlink:href="johf549139.f1"/> <graphic xlink:href="johf549139.f2"/>
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BMJ. 2008 Jul 10; 337:a494