Bariatric or weight loss surgery refers to a number of different procedures that can be performed to treat obesity. Procedures fall into three main types:

Malabsorptive - these procedures involve bypassing a section of the small intestine thus reducing the amount of food absorbed into the body.

Restrictive - these procedures involve reducing the size of the stomach, usually by creating a small pouch at the top of the stomach which limits the amount of food that can be eaten.

Malabsorptive/Restrictive Combination - these procedures combine both techniques e.g. gastric bypass surgery in which a small stomach pouch is formed and its outlet connected to part of the small intestine.