Bariatric surgery is a general term used to refer to medical procedures that involve alteration of the stomach to promote weight loss. While there are several types of bariatric surgery, each falls within one of three categories: those that work by reducing the stomach size, those that work by restricting the absorption of calories, and those that combine these functions. The most common types of bariatric surgery that work by reducing the size of the stomach are gastric banding and sleeve gastrectomy. Biliopancreatic diversion is the most commonly used caloric restriction procedure. Gastric bypass is a popular procedure that limits both stomach size and caloric absorption.
Among the different types of bariatric surgery are those procedures which promote weight loss by reducing the size of the stomach. When the stomach size is decreased, patients can take in only a fraction of the amount of food they could previously eat, leading them to shed excess pounds in the months and years that follow the procedure. Commonly performed procedures that work in this manner include gastric banding and sleeve gastrectomy. Gastric banding involves the placement of an adjustable band around a section of the stomach, and is among the least-risky types of bariatric surgery. In the more invasive and irreversible sleeve gastrectomy, a sizeable portion of the stomach is removed, leaving just a narrow, sleeve-shaped stomach behind.
Some types of bariatric surgery work by altering the stomach in such a way that the body’s ability to absorb calories is restricted. One of the most common caloric restriction procedures is biliopancreatic diversion. In this procedure, the stomach is reconfigured so that it connects to the small intestine at a lower point than normal. Since food bypasses a significant portion of the small intestine following this procedure, the amount of time in which the body can absorb calories from food during digestion is limited. While biliopancreatic diversion can be a highly effective weight loss tool, it also tends to cause serious nutritional deficiencies, and is thus used less often than other types of bariatric surgery.
The most commonly performed type of bariatric surgery, gastric bypass, restricts both stomach size and caloric absorption. During this procedure, a surgeon uses staples to seal off a large section of the stomach, creating a small stomach pouch. The surgeon then connects this pouch directly to the small intestine. Following the surgery, patients can only eat a small amount of food, and that food enters the intestines more quickly than normal. Gastric bypass tends to produce more dramatic weight loss than surgeries that only limit stomach size, but does not limit nutrient absorption as much as procedures like biliopancreatic diversion.