Weight loss and weight gain. A, left: simulated and measured changes of BW and FM resulting from a 1,000 kcal/day diet for 8 wk in obese women. A, right: simulated and measured changes of TEE, RMR, and PAE in response to imposed changes of EI, where the symbols are identical to those in Fig. 2. B, left: simulated and measured changes of BW and FM in response to 6 wk of overfeeding by 1,000 kcal/day in healthy young men. B, right: changes of TEE, RMR, and PAE, where the symbols are identical to those in Fig. 3. Data are presented as means ± SD.