Randomized trial reveals that physical activity and energy expenditure are associated with weight and body composition after RYGB.

Abstract

This study investigated the associations of both physical activity time (PA) and energy expenditure (EE) with weight and fat mass (FM) loss in patients following Roux-en-Y gastric bypass (RYGB) surgery. Ninety-six nondiabetic patients were included in this analysis. Post-RYGB patients were randomized in one of two treatments: A 6-month exercise training program (RYBG+EX) or lifestyle educational classes (RYGB). Body composition was assessed by dual-energy X-ray absorptiometry and computed tomography. Components of PA and EE were quantified by a multisensory device. Dose-response relationships of both PA and EE with weight loss and body composition were explored according to quartiles of change in steps per day. Patients in the highest quartiles of steps per day change lost more FM (3rd = -19.5 kg and 4th = -22.7 kg, P < 0.05) and abdominal adipose tissue (4th = -313 cm² , P < 0.05), maintained skeletal muscle mass (3rd = -3.1 cm² and 4th = -4.5 cm² , P <  0.05), and had greater reductions in resting metabolic rate. Decreases in sedentary EE and increases in light EE and age were significant predictors of both Δweight and ΔFM (R²  = 73.8% and R²  = 70.6%, respectively). Nondiabetic patients who perform higher, yet still modest, amounts of PA following RYGB have greater energy deficits and lose more weight and FM, while maintaining higher skeletal muscle mass.