Rachel K. Johnson
Dietary Intake—How Do We Measure What People Are <i>Really</i> Eating?
University of Vermont
successful obesity treatment depends combination diet modification increased physical activity 1 goal diet therapy instruct people longterm modifications reduce energy intake 1 frequent clinical encounters trained health professional physician registered dietitian initial 6 months therapy facilitate reaching goals therapy 2 important component clinical encounters assessing dietary intake treatment followup 2 aim paper identify commonly used methods estimate dietary intake identify strengths weaknesses make recommendations use treatment overweight obese patient traditional dietary intake methods rely information reported subjects methods include food records food frequency questionnaires ffqs 24hour recalls method strengths weaknesses related intended use ease administration validity food records typically obtained 3 7 days sevenday records historically used gold standard validating methods 3 based tactic assumption selfreported information valid correct however advent biomarkers food record known many weaknesses limit use validation studies biomarkers variables measured body fluids tissue independently reflect intake food component 4 food records require literate motivated subjects place high burden patients quality record declines relation number days recorded 5 actual process recording food intake lead patients change foodintake patterns 6 ffqs commonly used groups people provide estimates usual dietary intake time typically 6 months 1 year often used large cohort studies place individuals broad categories along distribution nutrient intake ffq lists specific foods asks subject eat often much eat hence ffq must culturespecific ie different lists foods developed assessing diverse diets groups hawaiians japanese chinese filipinos whites 7 short 60 food items long 100 food items ffqs developed 8 neither designed assess current energy intake important component diet therapy obesity treatment modified ffqs designed identification people high intake dietary fat andor low intakes fiber fruits vegetables 9 figures 1 2 questionnaires developed identify potential candidates enrollment intervention research studies may also useful clinicians seeking identify people needing diet counseling 9 fat screener fat screener fruitvegetablefiber screener associated scoring algorithms property block dietary data systems berkeley ca must obtain permission owner use tools please contact vendor licensing 510 7048514 wwwnutritionquestcom fruit vegetable fiber screener fat screener fruitvegetablefiber screener associated scoring algorithms property block dietary data systems berkeley ca must obtain permission owner use tools please contact vendor licensing 510 7048514 wwwnutritionquestcom 24hour recall designed quantitatively assess current nutrient intake 24hour recall conducted person telephone similar results 10 method requires shortterm memory recall unannounced diet changed method relatively brief 20 30 minutes subject burden less comparison food records appropriate use lowincome lowliteracy populations subjects need read write complete recall 11 disadvantages 24hour recall include inability single days intake describe usual diet 12 success recall depends memory cooperation communication ability subject lastly trained interviewer needed essential assess validity dietary intake methods determine method measuring people really eating traditionally face validity determined based comparison among methods example ffq often compared 7day food records 3 actually determine either method valid estimates dietary intake comparable two methods believed dietary methods validated using external independent markers energy intake biomarkers 13 doubly labeled water dlw currently widely used well accepted biomarker dlw provides accurate measure freeliving subjects total energy expenditure equivalent energy intake weightstable people dlw well accepted gold standard determine validity tools designed measure energy intake 13 use validation tool based principle energy balance person weight stable energy expenditure measured dlw must equal energy intake 14 15 high cost sophisticated technology associated dlw use date confined research laboratories around world lend routine use clinical settings used however research settings validate energy intakes obtained dietary intake method choice based dlw studies underreporting food intake known pervasive people report dietary intake lowenergy reporting occurs people report estimated food intakes lower true intake person reports energy intake biologically plausible identified lowenergy reporter 16 number factors associated lowenergy reporting including age sex body mass index well demographic psychological factors 17 based numerous papers published past decade lowenergy reporting consistently shown prevalent severe among obese subjects compared lean subjects 18 19 studies others found obese underestimate energy intake greater degree ranging 30 47 lean thus well accepted obese inclined underestimate dietary intake factors may predictive lowenergy reporting underlying cause solely people purposely underreporting also implementation dietary intake methods lowenergy reporting occurred simply across boardthat foods nutrients underreported degreethe solution problem would relatively simple correction factor could added dietaryintake data lowenergy reporters would bring intake nutrients line valid reporters unfortunately solution simple become clearer lowenergy reporters often fail report foods bad even sinful connotation 20 may need improve probing methods evaluate subject familiar standard measures improve accuracy total energyintake reporting large us survey 1224 8334 adults found lowenergy reporters comparing lowenergy reporters nonlowenergy reporters following among foods less likely reported cakespie savory snacks cheese white potatoes meat mixtures regular soft drinks fattype spreads condiments 21 british investigators found underreporters reported consuming significantly less cakes sugars fat breakfast cereals however found discernible differences reports bread potatoes meat vegetable fruit consumption underreporters subjects 22 time consensus literature whether much macronutrients differently reported research suggests lowenergy reporters report lower intakes fat percentage total energy higher intakes protein carbohydrate 17 23 others demonstrated reported added sugar intake significantly lower measured caused part omission snack foods dietary record 24 phenomenon lowenergy reporting important implications obesity treatment notion obese often report consuming calories lean probably related lowenergy reporting food intake obese subjects 19 hence important clinicians working obese patients aware problem understand identify clinicians apply goldberg cutoff extensively described goldberg et al 25 black et al 26 goldberg cutoff evaluates selfreported energy intakes estimated energy requirements defines cutoff limits identify obviously implausible intake values cutoff value valuable applied food frequency questionnaires designed represent persons usual eating habits period time precise measure energy intake briefly height weight measurements used predict basal metabolic rate standard formulas goldberg et al recommend schofield equations ratio estimated energy intake ei predicted basal metabolic rate bmr calculated eibmr ratio compared studyspecific cutoff value provided ref 25 represents lowest value eibmr could within defined bounds statistical probability reflect habitual energy expenditure given sedentary lifestyle example 4day mean estimate energy intake single subject recorded intakes would least 110 estimated bmr considered plausible 25 multiplepass 24hour recall method originally developed us department agriculture effort limit extent underreporting occurs selfreported food intake 27 method differs traditional 24hour recall interviewer uses five distinct passes garner information subjects food intake preceding 24 hours method described detail first pass termed quick list subject asked recall everything eaten previous day using recall strategy choose second pass termed forgotten food list interviewer probes subject possible forgotten foods ie sweets savory snacks non alcoholic beverages etc third pass termed time occasion subject states time foods eaten discusses eating occasion fourth step termed detailed cycle subject answers standardized questions us department agriculture developed probe subjects information pertaining food clarifies food portion sizes 28 food portion sizes estimated using twodimensional food models food models include common household measures dishes cups spoons bowls glasses geometric shapes circles rectangles wedges foodspecific gram weight descriptions 29 subjects also asked food consumed length time eating occasions final step termed final review probe interviewer probes try get additional food items consumed recorded part recall 28 typically multiplepass 24hour recalls entered computerbased nutrient analysis program obtain estimated energy intakes original multiplepass 24hour recall shown accurate young children ages 4 7 years 30 however underreporting occurred method adult women ages 19 46 years compared dlw measurements total energy expenditure 11 according conway et al 31 current multiplepass method accurate measure energy intake adult women controlled conditions hise et al 32 developed new method improve validity subjective dietary records among overweight people method entailed people eating university cafeteria 2 weeks food weighed food waste taken account 24hour food recall used snacks beverages meals 2week measurement period combination observerrecorded weighedfood records 24hour snack recalls shown valid measure ei dlw although method shown valid use method limited would difficult always weigh observe subjects intakes date dietary intake method shown immune underreporting older children adolescents adults 33 34 multiplepass 24hour recall designed estimate current nutrient intake attempts minimize problem lowenergy reporting recommended method choice estimating energy intake obesity treatment followup single administration multiplepass 24hour recall little use estimating peoples usual energy intake substantial intraindividual daytoday variation occurs food intake 12 thus recommended minimum 3 days intake including 1 weekend day collected done person telephone similar results 10 3day mean energy intake assessed underreporting using ratio energy intake estimated energy requirements established cutoffs 25 clinicians need screening questionnaires quickly accurately measure changes energy intake associated successful outcomes obesity treatment unfortunately date questionnaire developed lowering fat intake increasing fruit vegetable intake strategies may helpful reducing total energy intake promoting weight loss 2 35 hence simplified fat fiberfruitvegetable questionnaire figures 1 2 might useful determining patient lowered fat intake andor increased fruit vegetable intake however validity questionnaires ability detect dietary change obese patients tested several methods available estimate dietary intake developed categorize groups people longterm intake various nutrients epidemiological studies ffqs others designed estimate current nutrient intake food records 24hour recalls method strengths weaknesses none immune problem lowenergy reporting particularly among obese subjects multiplepass 24hour recall developed minimize problem lowenergy reporting measure current energy intake hence recommended method choice used least 3 days obesity treatment followup quick screening questionnaires developed identify people highfat lowfiberfruitvegetable intake questionnaires could used identify patients dietary patterns associated successful weight loss weight maintenance however efficacy use way tested dr johnsons research funded part vermont agricultural experiment station project vtns00718 author would like thank ms amy friedman bs assistance preparation manuscript