A diet high in carbohydrates with high glycemic indexes (GI) and glycemic load were linked to risk of coronary heart disease development in women in a large prospective study. Two cross-sectional studies showed that low-GI diets are associated with high HDL-cholesterol concentrations, especially in women. In a tightly controlled study of patients with type 2 diabetes, serum total cholesterol, LDL cholesterol, and apolipoprotein B concentrations fell more significantly after a low-GI diet than after a high-GI diet. In the same study, plasminogen activator inhibitor-1 concentrations were reduced by 58% after the low-GI diet. Insulin-stimulated glucose uptake by adipocytes was significantly higher in patients undergoing coronary artery bypass graft surgery after 4 wk of consuming a low-GI diet than after consuming a high-GI diet. The effects of low-GI diets may be mediated by changes in postprandial fatty acid concentrations or by hormonal signals from adipocytes, but a possible association of low-GI diets with some other dietary factor such as chromium must not be excluded. Proof of the clinical value of low-GI diets awaits prospective trials, which should include short-term observations covering periods of metabolic stress induced by surgery as well as long-term trials with clinical endpoints.