Bariatric surgery is a procedure used to restrict food intake or interrupt the digestive process in patients who are severely obese (typically more than 100 pounds overweight). It is used only after other methods, such as dietary changes, exercise and medication, have failed to bring an individual’s weight under control. 

There are two major types of bariatric surgery:

• Restrictive operations. Reduce food intake by narrowing the passage between the upper and lower parts of the stomach. Adjustable gastric banding, in which the passage is narrowed with a hollow band of silicone rubber, is an example of a restrictive operation.
  
  
• Restrictive/malabsorptive operations. Also called combined operations, these alter the small intestine so that less of it is involved in the digestive process. A Roux-en-Y gastric bypass, in which a small stomach pouch is created and attached to a Y-shaped section of the small intestine, is an example of a combined operation. This procedure allows food to bypass the lower stomach, the duodenum and the first portion of the jejunum.

These surgeries can help obese patients lose significant amounts of weight. However, they present certain health risks such as nutritional deficiencies, infection, blood clots and pneumonia. In some cases, bariatric surgery has led to death. However, death or infection occurs relatively rarely, according to the American Obesity Association.

Patients who have successful bariatric surgery will gradually return to a healthful diet after a period of time. There is no guarantee that patients will keep off the weight they have lost. The best way to increase the likelihood of maintaining weight loss is to eat a healthful diet, exercise regularly and make other physician-recommended lifestyle changes.