Open Roux-en-Y Gastric Bypass is the most common gastric bypass surgery utilized. In this procedure, a small part of the stomach is sectioned off creating a small pouch about the size of an adult’s thumb that restricts the amount of food you can eat (1). This pouch will only be capable of holding an ounce of food or less at a time, causing you to feel full quickly.

One end of the small intestine is brought up and attached to the stomach pouch (2). The other end of the small intestine, still connected to the now non-functional stomach remnant, is reconnected to the intestinal tract (3). This procedure will bypass four feet of intestine, rerouting your food, so that most of the stomach and the first part of the small intestine can no longer be utilized to absorb nutrients. Those calories and nutrients normally absorbed will be excreted instead.

Because Roux-en-Y Gastric Bypass changes the digestive process, lifelong nutritional supplements are essential to prevent malnutrition. It will be necessary to take a multivitamin in addition to B, iron and calcium supplements.

Most people who have gastric bypass surgery quickly begin to lose weight and continue to lose weight for up to 2 years. One study noted that people lost about 70% of their excess weight (the weight above what is considered healthy) in 1 to 4 years.