Free-living responses in energy balance to short-term overfeeding in adults differing in propensity for obesity

OBJECTIVE: Free-living adaptive responses to short term overfeeding were explored as predictors of longitudinal weight change in adults recruited as obesity-resistant (OR) or obesity-prone (OP) based on self-identification and personal/family weight history. METHODS: Adults identified as OP (n=21; BMI: 23.8±2.5 kg/m(2)) and OR (n=20; BMI: 20.2±2.1 kg/m(2)) completed 3 days of eucaloric (EU, 100% of energy needs) and 3 days of overfeeding (OF, 140% of energy needs). Following each condition, adaptive responses in physical activity (PA), total daily energy expenditure (TDEE), ad libitum energy intake (EI), and energy balance were objectively measured for 3 days in a free-living environment. Body mass and composition (DXA) were measured annually for 5 years. Adaptive responses to overfeeding 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. OP reduced their levels of PA following overfeeding while OR maintained or increased their PA. No other variables were found to correlate with weight gain. CONCLUSION: Failure to decrease sedentary behavior following short-term overfeeding is one mechanism that may be contributing to fat mass gain.