Cetislim containing the active ingredient cetilistat is considered a lipase inhibitor type of medication. The medication works by blocking the metabolization of fat within food so you do not digest it and the undigested fat will be passed through the body in bowel movement. The capsules should be used along with a low calorie, low fat diet and a proper exercise program to treat obesity. Reducing calorie intake and weight maintenance can help prevent and treat conditions such as high cholesterol, diabetes, hypertension and heart disease.