The Effects of Low Carbohydrate Diet on Liver Fat Content and Mitochondrial Fluxes

The purpose of this study is to examine whether a low carbohydrate diet decreases hepatic lipid content and changes hepatic mitochondrial flux in humans.

In this study, the investigators will examine whether a low carbohydrate diet will change hepatic lipid content and mitochondrial flux in humans. Before and after a low carbohydrate diet intervention, rates of hepatic mitochondrial flux will be assessed using positional isotopomer analysis of 3-13C-lactate during a 3 hour basal period. Rates of whole body ketogenesis will be determined using [13C4]β-hydroxybutyrate, and whole body glucose metabolism will be measured using [2H7]glucose. Body composition will be determined with bioelectrical impedance; hepatic lipid content will be measured with MRS. Whole-body oxidation of lipids, carbohydrates and protein will be determined using indirect calorimetry.

Change in hepatic triglyceride content will be measured using 1H magnetic resonance spectroscopy (MRS).

Change in the rate of hepatic mitochondrial flux (Vcs) will be assessed using 3-13C-lactate infusion.

Change in the rate of beta-hydroxybutyrate production will be assessed using [13C4]β-hydroxybutyrate infusion.

Inclusion Criteria: Age 18-70 Subjects must be able to communicate meaningfully with the investigator and must be legally competent to provide written informed consent Exclusion Criteria: chronic liver disease other than NAFLD chronic disease associated with hepatic steatosis such as diabetes mellitus use of drugs known to affect hepatic steatosis contraindications for MRI pregnancy or nursing at the time of the study