Representation of adults with class III obesity in studies assessing validity of self-reported energy intake using doubly labeled water: A systematic review

The measurement of habitual energy intake remains a challenge in nutrition research. High levels of misreporting, particularly among adults with obesity, have been observed when comparing self-reported energy intake to energy expenditure assessed via the doubly labeled water technique. Little is known about misreporting in adults with class III obesity (body mass index >= 40 kg/m2). This systematic review assessed the representation of adults with class III obesity in dietary validation studies and the validity of self-reported dietary energy intake for this group. Studies were included in this review if they: compared self-reported energy intake assessment method(s) to doubly labeled water, had participants >= 18 years old, and included participants with class III obesity. Fifteen studies met these criteria. Of those, eight included information about the number of participants with class III obesity. Out of 1784 participants across eight studies, 63 (3.5%) participants had class III obesity, compared to 9.2% of US adults with class III obesity. Six studies provided data on validity of energy intake assessment for class III obesity, with five of these showing underreporting. Participants with class III obesity are underrepresented in dietary validation studies. Future research should explore the role of weight status on dietary reporting accuracy.