Slim Trim Orlistat is combined with a reduced-calorie diet to promote weight loss.Slim Trim Orlistat also may be used to prevent weight gain after weight has been lost. Candidates for treatment with orlistat are patients who are obese with a body mass index (a measure of obesity) of more than 30 kg/m2. Candidates also include patients with a body mass index of between 27 and 30 kg/m2 if other risk factors for arteriosclerosis are present such ashigh blood pressure, diabetes, and elevated blood cholesterol or triglycerides. Based on several scientific studies, the average weight loss that is achieved when orlistat is taken as recommended for six months to one year is 12.4 to 13.4 pounds.