Bariatrics is that branch of medicine which deals with the treatment of obesity. Bariatric surgery is a technique used to treat obesity. It is also known as "gastric bypass surgery" and "bariatric lap band" surgery. It is a technique commonly used where a patient's weight poses serious health risks.

The Procedure

During bariatric surgery, the stomach is closed off, leaving only a small pouch about the size of a thumb for food. As a result, patients feel full on fewer calories. However, the most common procedure -- gastric-bypass surgery -- goes one step further. Surgeons not only shrink the stomach but also reroute the small intestine to thwart the digestive process, thereby decreasing the number of calories absorbed.

This is achieved by making a direct connection between the stomach and a lower section of the small intestine. The first segment, the duodenum, is skipped entirely. The duodenum's chief responsibility is igniting the digestive process and absorbing iron and calcium from food. So in the end, patients eat less and absorb fewer calories.


Bariatric surgery is typically quite effective. Most people who have bariatric surgery quickly begin to lose weight and continue to lose weight for up to 12 months. One study noted that people lost about one-third of their excess weight (the weight above what is considered healthy) in 1 to 4 years.(Balsiger)


Balsiger BM, et al. (2000). Prospective evaluation of Roux-en-Y gastric bypass surgery as primary operation for medically complicated obesity. Mayo Clinic Proceedings, 75: 673–680.

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