Early reduction of resting energy expenditure and successful weight loss after Roux-en-Y gastric bypass

摘要

Background: Weight loss and body composition changes after Roux-en-Y gastric bypass (RYGB) may influence resting energy expenditure (REE). The effect of lower REE after the procedure on long-term weight remains to be elucidated. Objective: To evaluate the effects of RYGB on REE and body composition 6 months after RYGB and to find out whether postsurgery REE affects weight at 12 and 18 months Setting: Tertiary referral hospital, southern Brazil Method: A prospective study involving 30 RYGB patients aged > 18 years was performed. Body composition was evaluated by X-ray absorptiometry and REE by indirect calorimetry. All patients were assessed before RYGB and 6 months postoperatively. Further analysis of weight was carried out at 12 and 18 months. Results: Baseline body mass index was 49 ± 9 kg/m2 and mean weight was 128 ± 19 kg, half of which comprised fat mass (50 ± 5%). Baseline mean REE was 2297 ±182 kcal/d. The percent . total weight loss was 26 ± 7%, 32 ± 9%, and 34 ± 9% at 6, 12, and 18 months, respectively. The percent excess weight loss gradually increased from 54 ± 12% at 6 months, to 67 ± 18% at 12 months, and 71 ± 19% at 18 months. REE was significantly lower at follow-up (—405 ± 108 kcal/d; P < .001). Furthermore, an inverse correlation between REE at 6 months and percent excess weight loss at 18 months (r = —.612; P = .035) was observed in the subgroup of patients whose REE decreased >405 kcal/d at 6 months. Conclusion: Patients undergoing RYGB who had a substantial drop in REE at 6 months may exhibit less long-term weight loss. (Surg Obes Relat Dis 2017;13:204-209.) ? 2017 American Society for Metabolic and Bariatric Surgery. All rights reserved.