Nonalcoholic steatohepatitis (NASH) occurs in 2-3% of the US population and carries a 15-20% chance of progression to cirrhosis. It is closely associated with obesity, hyperlipidemia and insulin resistance. Therapy usually includes recommendations to increase exercise and to begin weight reducing diets but these goals are variably achieved and their relative effects in conjunction with pharmacological intervention have not been well defined. Moreover, these lifestyle changes can confound results of treatment trials if not quantified through conditioning testing and measures of body fat. Polyunsaturated fatty acids, especially formulation rich in omega-3, are widely accepted and endorsed in the medical community for their beneficial effects on hyperlipidemia and coronary disease risk reduction. Recent data suggests that omega-3 fatty acids ameliorate hepatic steatosis in humans and in animal models of NASH by reducing hepatic fat content. We hypothesize that a one year course of omega-3 fatty acid (3gm/day) will produce improvement in NASH histological injury independent of changes in weight (BMI) or degree of conditioning measured by the lactate threshold. The effects of the supplement will be compared to a placebo group and controlled for these lifestyle changes.