More than one half of middle-aged Americans have undesirably high serum lipid levels. Diets high in fiber and carbohydrate and low in fat reduce serum lipid levels two to four times more than the widely recognized American Heart Association diet. High intake of soluble fiber is especially effective for lowering serum cholesterol levels; alcohol restriction and weight reduction help lower serum triglycerides. High-carbohydrate, high-fiber diets combined with regular exercise and healthy life-style hold great potential to reduce hyperlipidemia and the incidence of coronary artery disease in the United States.