Effects of Marked Weight Loss Induced by Gastric Bypass Surgery or Low-Calorie Diet Alone on Postprandial Glucose Disposal in Type 2 Diabetes

In people with obesity and diabetes, marked (∼20%) weight loss induced by behavioral diet therapy (BDT) causes a greater decrease in postprandial plasma glucose area under the curve than matched weight loss after Roux-en-Y gastric bypass (RYGB), even though insulin sensitivity and postprandial plasma insulin area under the curve are the same in both groups. We studied the effects of marked weight loss after BDT or RYGB on insulin-mediated glucose disposal (IMGD) and non-insulin-mediated glucose disposal. Weight loss induced by BDT, but not RYGB, increased IMGD. Postprandial glycemia improves more after marked weight loss induced by BDT than by RYGB because of increased IMGD after BDT but not RYGB.