Gastric Bypass Surgery And Weight Loss

Gastric bypass (also called bariatric surgery) closes off a large portion of the stomach, leaving only a pouch the size of an egg. Gastric bypass works by restricting food intake. Patients feel full after eating small amounts of food. Fewer calories are eaten and weight is lost. Gastric bypass patients typically lose 70% of their excess weight, most of it in the first year after surgery.

Gastric bypass surgery combines the creation of a small stomach pouch to restrict food intake and construction of bypasses of the duodenum and other segments of the small intestine to cause malabsorption (decreased ability to absorb nutrients from food).

There are two types of gastric bypass surgery: Roux-en-Y gastric bypass (RGB) and extensive gastric bypass (biliopancreatic diversion).

Roux-en-Y gastric bypass is the most common gastric bypass procedure performed in the U.S. First, a small stomach pouch is created by stapling part of the stomach together or by vertical banding. This limits how much food you can eat. Next, a Y-shaped section of the small intestine is attached to the pouch to allow food to bypass the duodenum as well as the first portion of the jejunum. This causes reduced calorie and nutrient absorption. This procedure can now be done with a laparoscope (a thin telescope-like instrument for viewing inside the abdomen) in some people. This involves using small incisions and generally has a more rapid recovery time.

In extensive gastric bypass