ASSESSMENT OF SELECTIVE UNDER-REPORTING OF FOOD-INTAKE BY BOTH OBESE AND NONOBESE WOMEN IN A METABOLIC FACILITY

OBJECTIVE: To investigate the degree of bias in under-reporting of foo d intake in obese and non-obese subjects, hypothesising that under-rep orting may be selective for either macronutrient content (carbohydrate (CHO), fat, protein, alcohol), specific food types or eating occasion s (meals, snacks). DESIGN: Thirty-three women (18 obese, 15 non-obese) were recruited to a long-stay metabolic facility for 24 h. Ad libitum food intake was covertly measured throughout the study and a reported food intake completed at the end of 24 h. RESULTS: Reported total dai ly energy intake was significantly lower than measured intake. Whilst meals were accurately reported, energy from snack foods eaten between meals was significantly under-reported. (P < 0.001) Reported total car bohydrate and added sugar intakes were significantly lower than measur ed, whilst reported protein and fat intakes were not significantly dif ferent from measured. Reported alcohol intake was also considerably lo wer than measured, but high variability prevented significance. CONCLU SIONS: In both obese and non-obese women the major cause of under-repo rting, as assessed by covert study design in subjects restricted withi n a metabolic facility, is the failure to report between-meal snack fo ods. There is some evidence for increased under-reporting in high CHO, but no evidence of a bias in under-reporting towards high fat or high protein foods.