What Is the glycemic load?
The glycemic load is a relatively new way to assess the impact of carbohydrate consumption on your blood sugar. It takes the GI into account but gives a fuller picture than the GI alone. A GI value tells you only how quickly a particular carbohydrate-containing food turns into sugar; it does not tell you how much of that carbohydrate is in a serving of a particular food. You need to know both things to understand a food's effect on blood sugar.
When you eat a carbohydrate-containing food, your blood sugar rises as the food is digested, then falls as the glucose is used by cells for energy or stored as fat for later use. The extent to which it rises and remains high depends on the amount of a carbohydrate in the food and the glycemic index of that food. The glycemic load combines these two factors to provide a measure of blood-sugar response to a particular food as well as the insulin demand produced by a normal serving of that food. For example, if a food contains very little carbohydrate, it will not have much impact on blood sugar and insulin levels, regardless of its glycemic index. On the other hand, if a given food has a high glycemic index and a high carbohydrate content, blood glucose and insulin will quickly increase.
How the glycemic load is calculated:
Glycemic Load = (GI of the food x amount of carbohydrate in the serving*) /100
For example, a medium orange has a GI value of 44 and contains 10 grams of carbohydrate. Its glycemic load is (44 x 10) /100 = 4.4. A small potato has a GI value of 90 and 15 grams of carbohydrate. It has a glycemic load of (90 x 15) /100 = 14. One small potato will raise your blood glucose level higher than one orange.
*The amount of carbohydrate in a serving of food can be found on the product label in the Nutrition Facts Panel of most packaged foods and in the nutrition information at the end of Canadian Living recipes.
Glycemic load range:
Low glycemic load = 10 or less
Medium glycemic load = 11 to 19
High glycemic load = 20 or more
The glycemic index can be used to compare foods, and the glycemic load can be used when you're deciding on the portion size of the food you plan to eat.
