Evaluation of the early effects of Roux-en-Y gastric bypass surgery combined with perioperative caloric restriction on hepatic fat in obese patients with type 2 diabetes as compared to caloric restriction alone

Background and rationale: Bariatric surgery has recently emerged as a new treatment for type 2 diabetes in obese patients. Diabetes reverses rapidly after the surgery, even before patients lose significant amount of weight. We propose to study the early effects of gastric bypass surgery on liver fat in obese patients with type 2 diabetes and investigate how changes in liver fat relate to resolution of diabetes. Study design: Obese patients with type 2 diabetes referred for gastric bypass surgery will be randomized to (i) gastric bypass surgery combined with 2 weeks of preoperative caloric restriction and 4 weeks of postoperative caloric restriction (the early surgery group) or (ii) 6 weeks of preoperative caloric restriction followed by gastric bypass surgery (the control group). Liver fat will be measured by MRI at 6 weeks after starting caloric restriction and compared between the 2 study groups. We will also study the relationship between liver fat and glucose levels in these patients. Significance: This study will evaluate the early effects of gastric bypass surgery on liver fat in patients with type 2 diabetes. This research can provide new insights into treating type 2 diabetes.