Free-Living Responses in Energy Balance to Short-Term Overfeeding in Adults Differing in Propensity for Obesity.

ABSTRACT

OBJECTIVE: Free-living adaptive responses to short-term overfeeding (OF) were explored as predictors of longitudinal weight change in adults classified as having obesity resistance (OR) or obesity proneness (OP) based on self-identification and personal/family weight history. METHODS: Adults identified as OP (n = 21; BMI 23.8 ± 2.5 kg/m2 ) and OR (n = 20; BMI 20.2 ± 2.1 kg/m2 ) completed 3 days of eucaloric feeding (EU; 100% of energy needs) and 3 days of OF (140% of energy needs). Following each condition, adaptive responses in physical activity (PA), total daily energy expenditure, ad libitum energy intake, and energy balance were objectively measured for 3 days in a free-living environment. Body mass and composition were measured annually by using dual-energy x-ray absorptiometry for 5 years. Adaptive responses to OF were correlated with 5-year changes in body mass and composition. RESULTS: Increases in sedentary time correlated with longitudinally measured changes in fat mass (r = 0.34, P = 0.04) in the cohort taken as a whole. Those with OP reduced their levels of PA following OF, whereas those with OR maintained or increased their PA. No other variables were found to correlate with weight gain. CONCLUSIONS: Failure to decrease sedentary behavior following short-term OF is one mechanism that may be contributing to fat mass gain.