The "Sleeve" is a restrictive procedure in which the surgeon creates a long tubular or sleeve-shaped stomach pouch. A large portion (about 70-80%) of the stomach is completely removed at the time of surgery. This procedure does not involve any re-routing of the intestinal tract and it is not reversible.
Patients are able to lose weight with this procedure because of the reduced stomach size, which allows for better portion control. In addition, the portion of the stomach that is removed is thought to be responsible for secreting a hormone called Ghrelin which controls appetite and hunger. By removing this portion of the stomach, the appetite hormone is reduced allowing patients to experience less hunger throughout the day.