2-5 Intermittent Caloric Restriction in HIV

Background: Weight gain can lead to obesity and diabetes even in people living with human immunodeficiency virus (HIV). Researchers want to see if the technique intermittent calorie restriction can help overweight people with HIV as an alternative to traditional diets. Objective: To see if intermittent calorie restriction leads to weight loss and improved blood sugar in obese people with HIV. Eligibility: Adults ages 18-65 with HIV who are obese and do not have diabetes Design: Participants will be screened with a medical history, physical exam, and blood and urine tests. Before starting treatment, participants will: * Have a nutritional consultation * Get a pedometer to record daily steps * Test a restricted diet for 1 day * Have a body x-ray At the baseline visit, participants will have: * Blood drawn after they drink a sugar drink * Questions about their health and eating * A nutritional consultation * Resting energy expenditure measured. Participants will fast overnight. Then they will lie down while a plastic bubble goes over the head and a plastic sheet covers the upper body. Oxygen flows into the bubble. * Liver stiffness test. A wand on the stomach releases sound waves like an ultrasound. For 12 weeks, some participants will be on a standard diet. Others will restrict how much food they eat 2 days a week. On those days they will eat about 25% of their recommended calories. Participants will keep a diary of their diet and steps. Participants will have 4 visits during the 12-week diet and 1 visit 12 weeks after the diet ends. They will repeat previous tests.