The most common weight-loss operation performed in the United States is gastric bypass surgery, aka Roux-en-Y, but a number of other bariatric procedures also induce remission of type 2 diabetes.

>> Gastric bypass surgery (Roux-en-Y) is a two-step operation that involves stapling the stomach to create a small food pouch about the size of a walnut and then connecting the pouch to a part of the intestine much farther down from where the stomach normally attaches to the small intestine. The smaller stomach pouch can hold only about an ounce of food; because of the bypass, fewer calories and less fat are
absorbed in the intestines.

>> Adjustable gastric band is a less invasive procedure in which an inflatable band or ring is placed around the stomach near its upper end to create a small pouch with a narrow opening into the rest of the stomach. The pouch holds only about an ounce of food, but the narrow passageway makes that food empty slowly in the stomach, contributing to a longer-lasting sense of fullness. Doctors can tighten or loosen the band later without surgery, depending on changes in a patient’s weight. The adjustable gastric band doesn’t require stapling the stomach or rerouting the intestines (as with gastric bypass), but weight loss may not be as dramatic, and only about 50 percent of patients experience remission from type 2 diabetes.

>> Vertical sleeve gastrectomy is a newer procedure that has been approved by several insurers. A simpler operation than gastric bypass, it involves stapling two thirds of the stomach, creating a new stomach that is the shape and size of a banana. There is no rerouting of the intestines. Though less is known about its effects on type 2 diabetes, a few small studies have reported remission rates comparable to those following gastric bypass.

>> Biliopancreatic diversion with a duodenal switch (sometimes simply called duodenal switch) starts with a sleeve gastrectomy but also rearranges the small intestine to reduce the absorption of calories while maintaining a part of the first section of the small intestine called the duodenum (hence the name). This surgery is now being done more frequently, and recent studies indicate that almost all patients get over their type 2 diabetes. But those who choose it are at higher risk for malabsorption and nutritional deficits.