The Gastric Sleeve procedure works in two ways. One, is that when you eat, the small sleeve or pouch of stomach that’s left behind fills with each bite of food. Filling of that part of the stomach sends signals to the brain and your brain thinks you have eaten a larger portion of food than you actually have. As a result, you feel satisfied and comfortable with smaller portions of food. The second reason the Gastric Sleeve is so effective for sustained weight loss is that it removes the part of the stomach that produces a hunger hormone called Ghrelin.