Sleeve gastrectomy

In a sleeve gastrectomy, part of the stomach is separated and removed from the body. The remaining section of the stomach is formed into a tube-like structure. This smaller stomach cannot hold as much food. It also produces less of the appetite-regulating hormone ghrelin, which may lessen your desire to eat. However, sleeve gastrectomy does not affect the absorption of calories and nutrients in the intestines.

Duodenal switch with biliopancreatic diversion

As with sleeve gastrectomy, this procedure begins with the surgeon removing a large part of the stomach. The valve that releases food to the small intestine is left, along with the first part of the small intestine, called the duodenum.

The surgeon then closes off the middle section of the intestine and attaches the last part directly to the duodenum. This is the duodenal switch.

The separated section of the intestine isn't removed from the body. Instead, it's reattached to the end of the intestine, allowing bile and pancreatic digestive juices to flow into this part of the intestine. This is the biliopancreatic diversion.

As a result of these changes, food bypasses most of the small intestine, limiting the absorption of calories and nutrients. This, together with the smaller size of the stomach, leads to weight loss.

Feb. 13, 2013 See more In-depth