Dynamic Post-Prandial Metabolism in Patients With Non-Alcoholic Fatty Liver Disease

Background: Metabolism refers to the many chemical pathways by which various compounds, including food, are processed and used in the body. People with non-alcoholic fatty liver disease (NAFLD) have too much fat in their liver cells, but what causes it is unclear. One explanation is that people with NAFLD process food and metabolize it differently than people without NAFLD. Researchers want to compare how food is metabolized in people with and without NAFLD. Objective: To better understand how food intake influences the development and progression of NAFLD. Eligibility: People ages 18 and older with NAFLD or with a non-NAFLD metabolic syndrome Healthy volunteers ages 18 and older Design: Participants will be screened with medical history, surveys, physical exam, and blood tests. This will have ultrasound of the abdomen. This uses sound waves to image internal organs. Participants will stay at the Clinical Center for 2 nights. They will fast he first night. On the second day they will: Have their metabolism monitored in a metabolism research room for 24 hours Have a catheter inserted into an arm vein for several blood tests Drink an Ensure Plus for breakfast Have solid meals for lunch and dinner Have several urine tests. The final morning, they will: Have more blood tests. Have a DXA test to measure the fat in the body. They will lie on their backs for 15-25 minutes while an x-ray machine is positioned over areas of the body.