(Recruiting) Sponsor(s): University of Pittsburgh ;NIH/NIDDK Conditions to be treated: Diabetes; Obesity Purpose: This investigation is being carried out to learn more about research findings from a study that was completed last year. Those findings revealed that within the skeletal muscle cells of individuals with type 2 diabetes, there was often damage to the mitochondria (the muscle cell’s power source or the machinery of the muscle cell that produces energy). In individuals with type 2 diabetes, the liver continues to release sugar even when sugar levels are normal; the pancreas is not able to produce and release insulin normally; and the muscle and fat cells no longer respond as effectively to insulin. These defects lead to an abnormal rise of sugar in the blood. In this study, we want both to look more closely at the mitochondria and see if there is potential for improving mitochondrial functioning (improving the machinery of the muscle cell that produces energy) and reversing mitochondrial damage through a weight loss or a combined exercise/weight loss program. The program you get assigned to will be determined by a process called randomization (like a flip of a coin). Interventions: Behavior:weight loss/ exercise Study type: Interventional Study Design Overview: Treatment Randomized Open Label Uncontrolled Factorial Assignment Age limit of subjects: 30 to 55 years of age Genders eligible for study: Both Official title: Primary Outcomes: To measure the functional capacity of mitochondria in skeletal muscle of those with T2DM and those at increased risk of developing T2DM Secondary Outcomes: To assess whether exercise and diet can improve mitochondrial function and morphology. Expected Total Enrollment: 49 Important dates: Start Date: 2003-12-01 Expected Completion Date: 2007-12-01 Last Followup: 2006-12-01Data Entry Closure: 2007-12-01 Contact information for recruiting centers: University of Pittsburgh, Pittsburgh, Pennsylvania, 15213, United States; Recruiting Carol A Kelley, RN 412-692-2973 KelleyC@dom.pitt.edu David E. Kelley, MD, Principal Investigator