Weight Loss Surgery How It Works Sleeve gastrectomy helps you gradually lose and control your weight by reducing the amount of food that your stomach can hold at one time. The system works by helping you control your food intake and supporting long term, sustainable weight loss.During the procedure, a thin vertical sleeve of stomach is created using a stapling device. This reduces your stomach to about the size of a banana. The unused portion of your stomach is then removed.In clinical studies, this procedure has helped patients lose an average of 66 percent of their excess weight, as well as help resolve type 2 diabetes, high blood pressure, high cholesterol and sleep apnea.No postoperative adjustments are required.After surgery, food passes through your digestive tract in the usual order. This allows your body to absorb vitamins and nutrients as it always has.