Weight loss relapse is common in reduced-overweight and reduced-obese persons. It is unclear whether adaptations in resting metabolism and activity-related thermogenesis may result in energy-sparing, thereby contributing to weight regain. We compared resting and daily activity-related energy expenditure in formerly overweight women (maintaining weight losses of ≥ 5%) to normal-weight, weight-stable women matched for body mass index (BMI) and age. Reduced-overweight (RO) and normal-weight (NW) women (N = 44) completed questionnaires for weight history, eating and physical activity behaviors. Measures included: BMI, body composition (bioelectrical impedance), resting energy expenditure and substrate oxidation, and daily activity-related energy expenditure (accelerometry). Groups were comparable for habitual energy intake, resting energy expenditure, resting fat and carbohydrate oxidation and daily activity-related thermogenesis. The RO group significantly over-estimated daily moderate intensity activity-related energy expenditure (270 min/wk) whereas the NW group did not (113 min/wk) (P = 0.02). Energy expenditure (resting and activity-related) was comparable in RO and NW women. With the exception of over-reporting moderate intensity physical activity, our findings suggest that formerly overweight women do not exhibit energy-sparing adaptations increasing the likelihood of weight regain.

Key words: Weight loss, weight regain, energy expenditure, fat oxidation, self-report, physical activity.