A healthy diet and exercise have improved the health of people without human immunodeficiency virus (HIV) who have Metabolic Syndrome. In this study we would like to find out if the same benefit can be seen in people with HIV and Metabolic Syndrome. Patients with Metabolic Syndrome usually have a large waist, high blood cholesterol levels, high blood pressure, and high blood sugar levels. These are risk factors, which may increase one's chance of developing heart disease and/or diabetes. The purpose of the study is to evaluate the effects of different methods of treating HIV associated Metabolic Syndrome. The groups are: 1) a lifestyle modification program plus metformin (also known as glucophage), 2) lifestyle modification plus placebo, 3) metformin alone or 4) placebo alone. The lifestyle modification program consists of nutrition and exercise sessions with the goal of improving body composition, heart health, and ways to lower the risk of developing diabetes.