Glycemic index measures how specific foods impact the blood sugar level. The glycemic index tool assigns a number to all foods that contain carbohydrates according to how foods impact blood sugar levels. Foods are classified as low, medium, or high glycemic foods and ranked on a scale of 0–100. The higher the GI of a specific food, the more it increases blood sugar levels. For example the glycemic index of orange juice is 66 and 76. The glycemic index of an orange is 40.
Diets with lower glycemic loads contain more whole grains, nuts, legumes, fruits, vegetables without starch and fewer foods with a high glycemic index, like potatoes, white rice, and white bread.