This procedure generates weight loss solely through gastric restriction (reduced stomach volume). The stomach is restricted by stapling and dividing it vertically and removing more than 85% of it. This part of the procedure is not reversible. The stomach that remains is shaped like a very slim banana and measures from 1-5 ounces. The nerves to the stomach and the outlet valve (pylorus) remain intact with the idea of preserving the functions of the stomach while drastically reducing the volume.

The surgery generates weight loss by restricting the amount of food (and therefore calories) that can be eaten by removing 85% or more of the stomach without bypassing the intestines or causing any gastrointestinal malabsorption. It is a purely restrictive operation, is currently indicated as an alternative to the Lap-Band procedure for low weight individuals and as a safe option for higher weight individuals. Due to the nature of stomach tissue to be “stretchy” there is a higher potential for late regain of weight with this surgical procedure.