All gastric bands work by restriction. The band divides the stomach into a small pouch above (about 5% of the stomach) with the main body of the stomach below.
When the gastric band is tightened, this small pouch acts as the stomach and restricts the amount of food that can be eaten. In other words the brain is “tricked” into thinking that the whole stomach is full, when in fact only the small pouch is full.
Even a small amount of food can produce a feeling of fullness so that overall calorie intake may be 50-60% less than usual, leading to weight loss. As the food is slowly digested in the pouch, it passes through the band into the normal stomach below.
