GCG and type 2 diabetes mellitus: In both T2D obese and T2D-free obese patients, bariatric surgery increases postprandial GLP-1 levels (from up to 3-fold pre-surgery and nearly 8-fold vs baseline after gastric bypass).297 Interestingly, gastric bypass and sleeve gastrectomy have been reported to induce similar improvements in glycaemic control, despite inferior GLP-1 levels and BMI decreased in patients that had undergone sleeve gastrectomy.296