Diets rich in high-glycemic-index foods, which cause quick and strong increases in blood sugar levels, have been linked to an increased risk for diabetes, (5) heart disease, (6, 7) and overweight, (8, 9,10) and there is preliminary work linking high-glycemic diets to age-related macular degeneration, (11) ovulatory infertility, (12) and colorectal cancer. (13) Foods with a low glycemic index have been shown to help control type 2 diabetes and improve weight loss. Other studies, though, have found that the glycemic index has little effect on weight or health. This sort of flip-flop is part of the normal process of science, and it means that the true value of the glycemic index remains to be determined. In the meantime, eating whole grains, beans, fruits, and vegetables—all foods with a low glycemic index—is indisputably good for many aspects of health.