Carbohydrate-restricted versus low-glycemic-index diets for the treatment of insulin resistance and metabolic syndrome.

Carbohydrate-restricted diets (CRD) and diets comprised of foods with a low glycemic index (low-GI) are postulated to improve insulin resistance and metabolic syndrome, potentially preventing the development of type 2 diabetes mellitus (T2DM). In this article, recent findings concerning the effects of CRD and low-GI diets on measures associated with the metabolic syndrome and T2DM are discussed. An important problem that is encountered when trying to compare the effects of these different diets is the heterogeneity of carbohydrate consumption (8-40% of total kcal) used in interventions examining the effects of CRD. In contrast, there is a consensus definition for low-GI foods. However, since both quantity and type of carbohydrate powerfully affect metabolic outcomes, this review emphasizes that control of these factors in future studies will be important for determining the efficacy of either dietary approach in preventing the development of T2DM.