Orlistat medication is used with a doctor-approved exercise, behavior change, and reduced-calorie diet program to help you lose weight. It is used by certain overweight people, such as those who are obese or have weight-related medical problems. Taking orlistat can also help keep you from gaining back weight you have lost. Losing weight and keeping it off can lessen the many health risks that come with obesity, including heart disease, diabetes, high blood pressure, and a shorter life.Dietary fats need to be broken down into smaller pieces before the body can absorb them. Orlistat works by blocking the enzyme that breaks down fats in your diet. This undigested fat then passes out of your body in your bowel movement. Orlistat does not block the absorption of calories from sugar and other non-fat foods, so you still need to restrict your total intake of calories.