Only three studies were of one year in duration. After one year, one study reported no difference in actual GI between the low-GI and control groups, and two studies reported no differences in HbA1c between the low-GI and control groups.1,2 Both the ADA and Academy of Nutrition and Dietetics note that definition of low-GI versus high-GI diets is complicated by differing definitions of high-GI or low-GI diets or quartiles (for example, definition of low-GI diets range from 38% to 77% and definitions for high-GI diets range from 63% to 98%).1–3 Other problems include the variability in GI response to carbohydrate-containing foods within and among individuals.