Behavioral and body size correlates of energy intake underreporting by obese and normal-weight women

Objective To examine behavioral and body size influences on the underreporting of energy intake by obese and normal-weight women. Design Seven-day estimated food records were kept by subjects before they participated in a 49-day residential study. Self-reported energy intake was compared with energy intake required to maintain a stable body weight during the residential study (reference standard). Energy intake bias and its relationship to various body size and behavioral measures were examined. Subjects Twenty-two, healthy, normal-weight (mean body mass index [BMI]=21.3) and obese (mean BMI=34.2) women aged 22 to 42 years were studied. Statistical analyses Analysis of variance, paired t test, simple linear regression, and Pearson correlation analyses were conducted. Results Mean energy intake from self-reported food records was underreported by normal-weight (-9.7%) and obese (-19.4%) women. BMI correlated inversely with the energy intake difference for normal-weight women (r=-.67, P=.02), whereas the Beck Depression Inventory correlated positively with the energy intake difference for obese women (r=.73, P<.01). Conclusion/applications Results suggest that body size and behavioral traits play a role in the ability of women to accurately self-report energy intake. BMI appears to be predictive of underreporting of energy intake by normal-weight women, whereas emotional factors related to depression appear to be more determinant of underreporting for obese women. Understanding causative factors of the underreporting phenomenon will help practicing dietitians to devise appropriate and realistic diet intervention plans that clients can follow to achieve meaningful change.