Main study parameters/endpoints: The primary study parameters are %SFA in the liver and DNL. %SFA in the liver will be determined using MRS and DNL will be determined by applying stable isotope techniques. The secondary study parameters are hepatic fat composition, measured as %MUFA and %PUFA in addition to %SFA using MRS, adipose tissue fat composition, determined using MRS and biopsies, and insulin sensitivity, measured by a hyperinsulinemic euglycemic 2- step clamp.