The incidence of type 2 diabetes should be reduced either by decreasing insulin demand or by improving insulin sensitivity. Jenkins et al . found that a low-glycemic-index diet containing mainly intact whole grains significantly reduced C-peptide concentrations compared with a high-glycemic-index diet containing primarily refined grain product. In this review, we examine evidence relating dietary glycemic index and glycemic load to type 2 diabetes incidence and the role of the form of dietary carbohydrate in the management of diabetes. Both metabolic and epidemiologic evidence suggests that replacing high-glycemic-index forms of carbohydrate with low-glycemic-index carbohydrate will reduce the risk of type 2 diabetes. Among patients with diabetes, the weight of evidence suggests that replacing high-glycemic-index with low-glycemic-index forms of carbohydrate will improve glycemic control and reduce hypoglycemic episodes among those treated with insulin
