P38 Changes in the body composition in patients undergoing bariatric surgery

Abstract

Introduction: The goal of losing weight in obese patients is the loss of fat mass (FM), however, a proportion of lean mass (LM) it´s also lost, it´s contributes to the metabolic rate. Skeletal muscle (SM) is an important component of LM and the best predictor of basal metabolic rate (BMR). Changes in body composition after bariatric surgery (BS) and BMR is controversial. The decrease in BMR may contribute to post-surgical weight regain. Bioimpedance (BIA) is a useful technique for measuring body composition.

Objective: To evaluate the changes in body composition after BS.

Material and method: Descriptive, observational, retrospective study. Anthropometric data and body composition analysis were collected before BS and 12 to 24 months after it. Gastric bypass (GBP) and sleeve gastrectomy (SG) were performed.

Results: 20 patients were included, 16 females (80%), 46.90 ± 9.6 years. SG was performed in 12 patients (60%) and GBP in 8 (40%). SM and FM loss, and BMR was similar in GBP and SG (p> 0.05).

Conclusions: After BS weight loss can negatively influence in the body composition. The decrease in SM can be associated with a decrease in BMR and predispose to weight regain. In our study, the loss of SM was significant without exceeding 22%, as shown was other studies. No differences were found between both surgical techniques. In our study, the decrease in BMR is proportional to the decrease in SM since the formula used to calculate BMR implies SM, but other authors who used other measurement methods for BMR obtained a high correlation between these parameters, although longitudinal studies have not confirmed it yet. Nutritional interventions and the indication of early physical activity could be a valuable the resource to prevent loss of SM in patients undergoing BS.