Sleeve gastrectomy is a surgical weight-loss procedure in which the stomach is reduced to about 20% to 15% of its original size, by surgical removal of a large portion of the stomach along the greater curvature. The result is a sleeve or tube like structure. The procedure doesn't permanently reduce the size of the stomach, and there could be some dilatation of the stomach later on in life. A sleeve gastrectomy also works because it removes the part of the stomach that produces Ghrelin, which is a hormone that stimulates appetite. The procedure is generally performed laparoscopically and is irreversible.