Gastric bypass is the most commonly performed bariatric procedure in the United States for the surgical treatment of morbid obesity. Nearly 140,000 of these procedures are performed in America every year. Gastric bypass works in two ways: restriction and malabsorption.

Restriction of large amounts of food

The stomach is stapled to create a small ‘gastric pouch’ that is connected to the rest of the small intestine. This reduces the actual size of the ‘functional’ stomach from about 400 ml to a mere 15 to20 ml and limits the amount of food consumed at one time, therefore ‘restricting’ food intake.

Malabsorption of nutrients

Bypassing the stomach and about 75 centimeters of the small intestines results in the malabsorption of fats and carbohydrates, which further adds to the efficacy of the procedure. The combination of malabsorption and restriction make gastric bypass an effective procedure for surgical weight-loss.

Gastric bypass also results in an effective resolution of major illnesses that ordinarily accompany obesity. Nearly 85 to 90 percent of overweight patients suffering from hypertension, diabetes, sleep apnea and other major illnesses will see a significant improvement or resolution after undergoing gastric bypass.

Biliopancreatic diversion (Scopinaro's operation) takes a different approach to promote weight loss. This operation limits the amount of food that can be absorbed rather than the amount that can be eaten. We ordinarily use this only in failures of previous restrictive operations.