It would seem logical that eating fatty foods would cause a fatty liver, but this is not the case. The liver does play an important role in the metabolism or breakdown of fats. Something goes wrong in this process of metabolism, but it is still not known what does cause fat to build-up in the liver. It is known that fat accumulates in the liver with a number of conditions. The most common is obesity. Fatty liver is also associated with diabetes mellitus, high blood triglycerides, and the heavy use of alcohol. It may occur with certain illnesses such as tuberculosis and malnutrition, intestinal bypass surgery for obesity, excess vitamin A in the body, or the use of certain drugs such as valproic acid (trade names: Depakene/Depakote) and corticosteroids (cortisone, prednisone). Sometimes fatty liver occurs as a complication of pregnancy.