Diet-induced Thermogenesis in Patients With Postoperative Roux-in-Y Gastric Bypass (RYGBP) Weight Regain

Introduction: According to the National Health and Nutrition Examination Survey 2009-2010, 78 million American adults are obese. Bariatric surgery can provide for a sustained long-term weight loss and the metabolic change caused by the surgery seems to be the main cause of this loss. Cross-sectional, prospective and experimental studies, carried out during the post-operative period of Roux-en-Y Gastric Bypass surgery (RYGBP) have shown an increase of over 200% in energy expenditure after meals Diet-induced Thermogenesis (DIT), a specific component of energy expenditure) when compared with obese patients. However, despite this metabolic improvement, 20-50% of the patients can suffer weight regain about 2 years after surgery. So one question whether such metabolic benefits remain active following post-operative weight regain, or if the disappearance or decrease of these metabolic benefits may be seen as causes of this weight regain. Objective:To evaluate whether there are DIT differences between patients who maintained weight loss and those who regained weight in the late postoperative (postop) period of RYGBP and those who continue with preoperative (preop) obesity.