Response of total and regional lean tissue and skeletal muscle to a program of energy restriction and resistance exercise.

We evaluated the effects of energy restriction and resistance exercise on lean tissue (LT), skeletal muscle (SM) and adipose tissue (AT) in fourteen obese women. The prescribed diet created a daily 1000 kilocalorie (4.18 MJ) deficit. LT, SM and AT were measured using a magnetic resonance imaging (MRI) model whereby 41 transverse images were acquired over the entire body. Although significant (P < 0.01) losses were observed for bodyweight (-10.4 +/- 2.7 kg), and total AT volume (-9.8 +/- 2.5 l), no significant changes were observed for whole body LT (P > 0.05). For MRI-LT this observation remained true for upper and lower body regions. Measurement of MRI-SM in the appendicular region revealed that SM was preserved in both the arm and leg regions (P > 0.05). These findings provide evidence that lean tissues, in particular skeletal muscle, are preserved and adiposity is substantially reduced in response to weight loss induced by the combination of resistance exercise and moderate energy restriction.