Understanding the Glycemic Index and Glycemic Load

Important information about the glycemic index:

• The glycemic index (GI) is a tool to estimate the rise in blood sugar after eating different types of carbohydrates. 

• Foods are ranked 1-100 based on how quickly they increase blood sugar compared to a reference food, usually either glucose or white bread.

• Foods with a high glycemic index may raise blood glucose more quickly than foods with a medium or low glycemic index.

• Presence of dietary fat and fiber may lower the glycemic index of a food.

• Eating a low glycemic index food does not necessarily mean it is a healthier food choice. For example: watermelon and jellybeans are both considered high glycemic index, but watermelon is a healthier food to eat.

• The ranking of foods does not indicate how "healthy" they are. For instance some fruits may be considered high GI foods. However, this does not mean they should be avoided.

Other factors that affect the glycemic index include:

• Ripeness and storage time: The riper a fruit or vegetable, the higher the glycemic index.

• Processing: Generally, the more something is processed, the higher the glycemic index.

• Cooking method: How long a food is cooked can change the glycemic index. For example, firm-cooked pasta has a lower glycemic index than soft-cooked pasta.

• Variety: For instance not all types of rice have the same glycemic index.

The glycemic index value reflects the type of carbohydrate in the food, not the amount of carbohydrate eaten.

The glycemic index of a food may be different when combined with other foods. If you eat a high glycemic index food, you can combine it with a mixed meal or low glycemic index food to balance the effect on the blood sugar level.

Example of glycemic index:

• It is a number assigned to a food based on how quickly it will increase blood sugar compared to an equal portion of another food.

• Pure glucose has the highest glycemic index of 100.

• The glycemic index for bananas is 51.

This means bananas will not raise the blood sugar as high or fast as pure glucose.

Glycemic load (GL):

• The glycemic load gives a more accurate picture of a food's real-life impact on blood sugars than using glycemic index alone. The glycemic load shows the effect that a specific amount of a carb-containing food has on blood sugar.

• Eating a smaller amount of a high glycemic index food can lower the glycemic load and blood sugar response.

• The glycemic load of a portion of a food = (glycemic index x grams of carb per serving) ÷ 100.

Meal planning with the glycemic index and glycemic load:

Make healthy choices like fruit, vegetables, whole grains, low fat or fat-free dairy foods, and lean proteins.

Consider the glycemic index and glycemic load of foods when making combinations for meals and snacks.

• Choose low and medium glycemic index and glycemic load foods more often.

• If the food glycemic index is high, eat a smaller amount to lower the glycemic load.

Glycemic index of common foods:

Fruit

Low (less than 55): Apples, orange, banana, peach, cherries, pear, grapefruit, plum, grapes, strawberries, mango, dried apricots; juices including: apple, cranberry, grapefruit, orange, pineapple, tomato

Medium (55-70): Cantaloupe, fruit cocktail, kiwi, papaya, pineapple, raisins, plantain

High (greater than 70): Watermelon

Vegetables and beans

Low (less than 55): Broccoli, lima beans, cabbage, mushrooms, carrots, onions, green peas, peppers, lettuce, tomatoes, peeled and boiled yams, corn on the cob, boiled sweet potato, butternut squash, boiled parsnips, boiled beans including kidney, black, pinto, garbanzo, and baked beans, lentils, black-eyed peas and split peas

Medium (55-70): Beets, sweet corn, pumpkin, white potato with skin, roasted potatoes

High (greater than 70): Baked sweet potato, baked potato without skin, mashed or instant mashed potatoes, red potato boiled with skin

Grains

Low (less than 55): Barley, pumpernickel and sourdough breads, buckwheat, corn and wheat tortillas old-fashioned or steal-cut oatmeal, pasta including whole wheat, white, rice and egg pasta, chapatti

Medium (55-70): Muesli, rye bread, croissant, hamburger bun, whole-wheat pita, taco shell, cornmeal, couscous, regular Cream of Wheat, pancakes, quick oats (1 minute), udon noodles, rice (arborio, basmati, brown long grain, and wild)

High (greater than 70): Waffles, bagel, baguette, whole wheat, white wheat, or white breads, instant Cream of Wheat, instant oatmeal, kaiser roll stuffing rice (instant, short grain white, sticky)

Dairy products and non-dairy milk

Low (less than 55): Milk, yogurt, soy milk

Medium (55-70): None

High (greater than 70): Rice milk

Sweets and snacks

Low (less than 55): Cashews, hummus, Peanut M&Ms candy, milk chocolate, chocolate, peanuts, walnuts potato chips, pound cake

Medium (55-70): Angel food cake, candy bars, cookies, corn chips, muffins, pie crust, whole wheat crackers, popcorn

High (greater than 70): Doughnut, graham crackers, jellybeans, LifeSavers, pretzels, rice cakes, rice crackers, saltines, skittles, water crackers

Drinks

Low (less than 55): Water, sugar-free drinks, milk

Medium (55-70): Soda and soft drinks

High (greater than 70): Sports drinks

Resource:Glycemic Index-Sydney University

Reviewed May 2025 by Lauren Beebie, RD