title: Measurements of total energy expenditure provide insights into the validity of dietary measurements of energy intake.
abstract: The quantification of errors inherent in methods of measuring dietary intake has been handicapped by the absence of independent markers for testing their validity. The doubly labeled water technique permits a precise measure of energy expenditure in free-living persons. Because energy expenditure must equal energy intake in populations in energy balance, this technique may be used to validate the assessment of energy intake. A series of studies demonstrated good agreement between mean energy intake and mean energy expenditure when food intake was recorded by observers or when it was self-reported by normal-weight, self-selected, highly motivated volunteer subjects using weighed records. However, in randomly recruited men and women, energy intake by weighed records was 82% and 81%, of energy expenditure, respectively, indicating underestimation of habitual intake. Men and women in the lowest third of reported intake recorded energy expenditure of only 69% and 61%, respectively. Reported intake of obese and previously obese women was only 73% and 64% of expenditure, whether measured by weighed record or by diet history, confirming suspicions that these subjects misrepresented their intake. Acceptable weighed records were obtained from 7- and 9-year-olds whereas 15- and 18-year-olds underestimated intake. Diet histories taken from the same children tended to overestimate intake. These studies suggest that, ideally, all dietary studies should include independent measures of validity.
authors.affiliation: Dunn Clinical Nutrition Centre, Cambridge, United Kingdom.
authors.forename: A E
authors.initials: AE
authors.lastname: Black
authors.forename: A M
authors.initials: AM
authors.lastname: Prentice
authors.forename: G R
authors.initials: GR
authors.lastname: Goldberg
authors.forename: S A
authors.initials: SA
authors.lastname: Jebb
authors.forename: S A
authors.initials: SA
authors.lastname: Bingham
authors.forename: M B
authors.initials: MB
authors.lastname: Livingstone
authors.forename: W A
authors.initials: WA
authors.lastname: Coward
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004032:Diet / Q000379:methods; D015930:Diet Records; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000178:diet therapy / Q000378:metabolism; D011897:Random Allocation