Weight loss, weight maintenance, and adaptive thermogenesis

Background: Diet-induced weight loss is accompanied by adaptive thermogenesis, ie, a disproportional or greater than expected reduction of resting metabolic rate (RMR). Objective: The aim of this study was to investigate whether adaptive thermogenesis is sustained during weight maintenance after weight loss. Design: Subjects were 22 men and 69 women [mean +/- SD age: 40 +/- 9 y; body mass index (BMI; in kg/m(2)): 31.9 +/- 3.0]. They followed a very-low-energy diet for 8 wk, followed by a 44-wk period of weight maintenance. Body composition was assessed with a 3-compartment model based on body weight, total body water (deuterium dilution), and body volume. RMR was measured (RMRm) with a ventilated hood. In addition, RMR was predicted (RMRp) on the basis of the measured body composition: RMRp (MJ/d) = 0.024 X fat mass (kg) + 0.102 X fat-free mass (kg) + 0.85. Measurements took place before the diet and 8, 20, and 52 wk after the start of the diet. Results: The ratio of RMRm to RMRp decreased from 1.004 +/- 0.077 before the diet to 0.963 +/- 0.073 after the diet (P < 0.001), and the decrease was sustained after 20 wk (0.983 +/- 0.063; P < 0.01) and 52 wk (0.984 +/- 0.068; P < 0.01). RMRm/RMRp was correlated with the weight loss after 8 wk (P < 0.01), 20 wk (P < 0.05), and 52 wk (P < 0.05). Conclusion: Weight loss results in adaptive thermogenesis, and there is no indication for a change in adaptive thermogenesis up to 1 y, when weight loss is maintained. This trial was registered at clinicaltrials. gov as NCT01015508. Am J Clin Nutr 2013;97:990-4.