A band is placed around the upper part of the stomach. On the inside of this band, there is an inflatable balloon, which is connected to an access port that is under the skin on your belly. The band can be tightened by placing a needle into the port and filling the balloon (band) with fluid, to adjust the passage to the stomach. This technique divides the stomach into two parts, a small pouch at the top of the stomach (20 ml) and the actual stomach.
The pouch fills with food quickly, and the band slows the passage of food from the pouch to the lower part of the stomach. As the upper part of the stomach registers as full, satiety is inducted quicker.