Acute and longer-term body composition changes after bariatric surgery

Abstract

Background: Bariatric surgery induces weight loss but its acute and longer-term effects on body composition (BC) are largely unknown. Objectives: To determine the BC changes in obese French patients after sleeve gastrectomy (SG) at 1 and 12 months. Setting: Obesity Reference Center, University Hospital of Montpellier, France. Methods: Whole and localized BC (lean tissue mass [LTM] and fat mass [FM]) and abdominal adiposity, including total adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue, were determined by dual-energy X-ray absorptiometry in 30 obese patients (25 women, 83.3%) just before SG and 1 and 12 months later. Results: The mean weight loss was −9.7 ± 2.6 kg at 1 month and −32.1 ± 10.3 kg at 12 months. This weight loss was due to an equivalent decrease in LTM and FM in the acute phase, while FM loss appeared to be the main cause in the chronic phase. For each component (LTM and FM), the loss was relatively homogeneous across sites. Compared with the presurgical values, android and gynoid tissue and total adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue changed significantly over the 12-month period. No basal clinical parameter was predictive of the variation in LTM, whereas age and the whole-body LTM/FM ratio were associated with the decrease in FM. Conclusion: This study demonstrates that SG induces a clear modification in BC, characterized by a decrease in LTM in the acute phase and sustained FM loss in the first year. These results suggest that the early phase should be targeted for strategies to reduce LTM loss, which is a longer-term weight-regain criterion. Further studies to investigate the potential advantages of visceral adipose tissue compared with whole-body FM for improving post-SG co-morbidities should be performed.