For reference, pure glucose has a glycemic index of 100. Barley has a glycemic index of 26: White rice has a high glycemic index, ranging from 72 to 83, which means it increases blood sugar levels much faster than brown rice. Brown rice has an average glycemic index of 55. Eating lots of white rice has been linked to an increased risk of developing type 2 diabetes. I avoid rice. Japan doesn't have an obesity problem, but they have a diabetes problem. They eat a lot of rice.