Resting Energy Expenditure and Body Composition of Women with Weight Regain 24 Months After Bariatric Surgery

Weight regain 24 months after Roux-en-Y gastric bypass (RYGB) and low protein intake in patients without protein supplementation can favor fat-free mass loss and reduce resting energy expenditure (REE). We aimed to assess REE and its association with the body composition of women with weight regain and no protein supplementation in the late postoperative period of RYGB. We determined the body mass index (BMI), REE by indirect calorimetry, body composition by tetrapolar bioelectrical impedance analysis, and energy intake by two 24-h recalls of 34 patients with at least 5 % of weight regain and no protein supplementation. The software SPSS v.17 analyzed the data calculating measures of central tendency and dispersion and using Pearson's correlation to test the association between the variables and the multivariate linear regression model at a p < 0.05 significance level. Postoperative period was positively associated with weight regain (r = 0.39; p = 0.023). The mean percentages of fat and fat-free masses were 45.1 +/- 8.3 % and 54.3 +/- 8.1 %, respectively. The mean REE was 1424.7 +/- 187.2 kcal (14 kcal/kg of the current weight), mean energy intake was 1258.6 +/- 454.3 kcal, and mean protein intake was 0.9 g/kg of the ideal weight +/- 0.3. Fat-free mass was positively associated with REE regardless of protein intake and postoperative period. Female bariatric patients with weight regain and no protein supplementation lose fat-free mass, lowering their REE. Health practices that promote maintenance of BMI and body composition may lead to improved outcomes of bariatric surgery.