A gastric sleeve is a surgical procedure that reduces the size of the stomach, typically by about 80%. This is done by removing a large portion of the stomach, creating a smaller, tube-shaped stomach. The procedure is typically performed laparoscopically, meaning through small incisions in the abdomen. Gastric sleeve surgery can help people lose weight by limiting the amount of food they can eat and by reducing the production of ghrelin, a hormone that stimulates appetite.