Energy expenditure and skeletal muscle. Percent change (mean ± SEM) from values at Wt_initial of energy expenditure, skeletal muscle work efficiency, and fuel utilization. Administration of leptin to weight-reduced subjects reversed the significant decline in TEE and NREE associated with maintenance of a 10% reduced body weight. Effects of weight loss and exogenous leptin on skeletal muscle gross mechanical work efficiency (kcal/min energy expended above resting per kcal/min work generated) and fuel utilization (derived from RQ; ref. 87) were only evident at low levels of work (bicycling to generate 10 W of power). Mean ± SEM values at each weight plateau are presented in Supplemental Table 1, and individual values are presented in Supplemental Figure 1. *P < 0.05 versus 0; ^†P < 0.05 versus Wt_–10%. GME, gross mechanical efficiency.