Does laparoscopic gastric bypass result in a healthier body composition? An affirmative answer

Background: Bariatric surgery results in sustained weight loss. While weight loss is the goal of bariatric surgery, fat loss and muscle conservation are germaine goals. This study investigated the hypothesis that body composition would significantly change after laparoscopic Roux-en-Y gastric bypass (LRYGBP). Methods: Patients undergoing LRYGBP were studied. Percent fat and percent water were calculated via bioelectrical impedance analysis (BIA). Waist and hip circumference were measured in all patients as well. Measurements were taken preoperatively, and at 1 month, 3 months, 6 months, and 1 year. Non-parametric ANOVA was utilized for statistical analysis. Results: There were 151 patients included in this study. Fat percentage (48.6 +/- 10.0 vs 34.6 +/- 10.8; P<0.001), total fat mass (141 +/- 37 vs 67 30; P<0.0001) and total water mass (108 27 vs 93 23; P<0.0001) decreased postoperatively at 1 year. Water percentage increased postoperatively at 1 year (37.0 +/- 6.6 vs 52.5 +/- 3.3; P<0.001). Waist:hip ratio improved from preoperatively to 1 year postoperatively (0.895 +/- 0.115 vs 0.811 +/- 0.076; P<0.001). Conclusions: Bariatric surgery results not only in fat loss but also in a change in body composition. Improved waist:hip ratio, fat percentage decreases, and water percentage increases all indicate an overall healthy body composition. While weight loss is important, improvement in body composition should be another recognized benefit of bariatric surgery.