What is glycemic load?
The glycemic load (GL) is a relatively new way to measure how the intake of carbohydrates affects blood sugar levels. It is often used in tandem with glycemic index (GI), which helps determine how quickly food is digested and absorbed into your system. The quicker it is absorbed, the faster blood sugar levels rise. But the glycemic index does not tell you how much carbohydrate is in a particular food -- the glycemic load does.
The glycemic load considers the serving size of the food and calculates the number of carbohydrates in that particular serving of food. As a result, you have a more accurate means of predicting how the carbohydrates of a given food will affect your blood sugar.
Glycemic load formula
Here’s the formula for calculating glycemic load: Multiply the GI value of a food by the amount of carbohydrate per serving and divide the result by 100. You can then measure the glycemic load accordingly:
- 20 or more is high
- 11-19 medium
- 10 or less is low
For example, watermelon has a high GI ranking of 76. Using only the GI, you might be reluctant to eat watermelon, fearing a rapid rise in glucose. But when you bring the glycemic load into consideration, you see that a cup of watermelon has only about 11 carbohydrates and the glycemic load of watermelon is 8, which falls in the low range for raising your blood sugar.
A rule of thumb that applies most of the time: Foods that have a low glycemic load almost always have a low glycemic index.
Here are examples of the glycemic load of some foods:
- Steamed Broccoli (1/2 cup) - 1
- Cashews (2 oz) – 3
- 2% Milk (1 cup) – 4
- Ice cream (1 cup) – 8
- Apple juice (1 cup) – 12
- Cooked oatmeal (1 cup) – 16
- Corn flakes (1 cup) - 27
- Raisins (1/2 cup) – 28
Foster-Powell, K., Holt, S., Brand-Miller, J.C. International table of glycemic index and glycemic load values: 2002. American Journal of Clinical Nutrition Vol. 76, No. 1, 5-56, 2002. http://www.ajcn.org/cgi/reprint/76/1/5.pdf