The study has two phases. In Phase I, liver samples from patients undergoing bariatric surgery or a diagnostic liver biopsy will be tested for the ability to burn fatty acids. In Phase II, patients with nonalcoholic fatty liver disease will participate in either a nine-month lifestyle treatment program or undergo standard care. The goal is to determine how weight loss and exercise improve liver health.
Inpatient comprehensive metabolic tests are performed before and after the nine-months.