Longitudinal Cohort Study Comparing 2 Surgical Techniques in Patients With Class 3 Obesity and Type 2 Diabetes

Wight loss surgery provides good glycemic control in type 2 diabetes. The technique of "Roux-en-Y gastric bypass" is more effective than the "Adjustable Gastric Band" on weight loss. This longitudinal cohort study will compare the effectiveness of the Roux-en-Y gastric bypass and Adjustable Gastric Banding on glycemic control in type 2 diabetes and explore the responsible mechanisms. The evaluation will be made preoperatively and 1 year later as assessed by the decline in HbA1c. An evaluation will also be carried out after a weight loss of 10% to indicate whether the observed difference is independent of weight loss.