Is lean body mass decreased after obesity treatment by adjustable gastric banding?

Background: There is concern that surgically-induced weight loss in obese subjects is associated with a disproportionate decrease in lean body mass (LBM) and in skeletal muscle mass (SMM), a major constituent of LBM. To address this issue, 1) we measured total and regional body composition following gastric banding in a group of obese subjects, and 2) we compared these data to those of a non-surgical control group of similar age and body size. Methods: Body composition was assessed by dual-energy X-ray absorptiometry (DEXA) before and after laparoscopic adjustable silicone gastric banding (LAGB) in 32 women (after 1 year: age 43.7 +/- 8.4 years, BMI 36.4 +/- 5.9 kg/m(2), mean +/- SD), and in 117 control women (age 44.5 +/- 7.5 years; BMI 36.7 +/- 5.5 kg/m(2)) referred for non-surgical weight management, prior to weight loss. SMM was estimated using a published equation based on LBM of the extremities (appendicular LBM). Results: 1 year after LAGB, body weight loss (-23.7 +/- 11.6 kg, p < 10(-6)) was mainly due to decreased fat mass (-21.2 +/- 11.2 kg, p < 10(-6)), and total LBM was modestly, although significantly, decreased (-2.1 +/- 4.2 kg, P=0.01). Appendicular LBM (-0.7 +/- 2.7 kg) and total SMM (-0.9 +/- 3.0 kg) were not significantly modified. None of the body composition variables was significantly decreased in weight-reduced subjects compared to the control group, especially appendicular LBM and total SMM. Conclusions: Results provide no evidence for a decrease in appendicular LBM and total SMM with weight loss following LAGB. Follow-up of these obese patients revealed a very favorable pattern of change in total and regional body composition, with preservation of muscle mass.