Bariatric surgery is a type of weight loss surgery that is performed on individuals who are severely obese. The most common types of bariatric surgery are gastric bypass, gastric sleeve, and gastric banding. These procedures work by reducing the size of the stomach, limiting the amount of food that can be eaten, and/or altering the way that the body absorbs calories. Bariatric surgery can be effective in helping people to lose a significant amount of weight and improve their overall health. It is typically reserved for individuals who have been unable to lose weight through other means, such as diet and exercise.