Effects of Roflumilast on Insulin and Blood Sugar Levels in Prediabetic Overweight and Obese Individuals

Background: \- Roflumilast is a drug used to treat chronic obstructive pulmonary disease (COPD). It is designed to help reduce lung inflammation. However, during testing, roflumilast also appeared to reduce high blood sugar levels in people with COPD and type 2 diabetes. Other tests showed that roflumilast also improved blood sugar levels in people who only had type 2 diabetes. Researchers want to see how roflumilast affects insulin and blood sugar levels in overweight or obese people who are not diabetic, but who have high blood sugar levels. Objectives: \- To see how well roflumilast improves blood sugar and insulin levels in prediabetic overweight or obese individuals. Eligibility: \- Individuals between 30 to 65 years old who are overweight or obese (body mass index of 24.9 to 39.9 kg/m2) and have elevated blood sugar levels. Design: * This study will last approximately 8 weeks. Participants will have approximately five study visits over about 7 weeks. Two of these visits will be overnight inpatient stays. * Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. They will also have a 3-day diet and exercise assessment with a dietitian. * In Week 1, participants will have a special diet for 2 days to keep their regular weight. They will then have a 2-day inpatient stay. During their stay, they will have multiple tests, including blood sugar tests and full body scans. They may provide a fat and muscle tissue biopsy sample. They will then receive the study drug to take during the study. * In Week 2, participants will repeat the diet study from the screening visit. They will receive a different dose of the study drug. * In Week 3, participants will review their diet results and have blood and urine tests. * In Week 5, participants will repeat the diet and exercise study from the screening visit. * In Week 6, participants will repeat the inpatient studies and tests from Week 1. In the last week, part