The role of carbohydrates in cardiovascular disease prevention has garnered increasing attention due to accumulating evidence showing deleterious effects of low-fat, high-carbohydrate diets on serum triglycerides and high-density lipoprotein (HDL) cholesterol. Researchers argue that classifying carbohydrates based on their capacity for increasing blood glucose (termed the glycemic index ) is a useful tool for elucidating the effects of carbohydrate-rich foods on glucose and lipid metabolism. Several epidemiologic reports show that lower dietary GI is associated with lower serum triglycerides and higher HDL cholesterol. Results from intervention studies show that substituting low-GI for high-GI foods in a low-fat, high- carbohydrate diet lowers serum triglycerides by 15% to 25%. The available evidence to date suggests that the glycemic index of foods will be an important factor in future dietary prevention research.