What is the Glycemic Index?

The Glycemic Index (GI) is a way of measuring the relative impact of foods on blood sugar levels. Foods with a high glycemic index have carbohydrates that the body can quickly convert to sugar, which makes them more likely to cause a quick rise in blood sugar. Many popular diets (Atkins and South Beach, for example) include food choices based on the glycemic index.

To determine the glycemic index of a food, human subjects are given a portion of a single food and their blood sugar is tested at intervals. The resulting response curve is compared to a control substance (either glucose or white bread) and assigned a numerical value. Glucose (or white bread) is given an arbitrary rating of 100, and all other foods are measured relative to that. Foods that rate above 100 are foods whose carbohydrates digest very quickly and are likely to raise the blood sugar immediately, while those with an index lower than 100 have less impact on the blood sugar.

What is Glycemic Load?

Like the glycemic index, the Glycemic Load (GL) of a food is used to characterize its potential effect on blood sugar. A food may have a high glycemic index, meaning the carbohydrate it contains will quickly convert to sugar, but if that food does not contain much carbohydrate per average serving, there will not be much impact on the blood sugar.

To calculate the glycemic load of a food, multiply its glycemic index by the number of digestible (non-fiber) carbohydrates in a single serving, then divide by 100. That number may be interpreted as follows:

The amount of carbohydrates in one teaspoon of coco palm sugar is 5g.

Once can see that even though the apple has fewer carbohydrates, the glycemic load of the coco palm sugar is actually lower.



Illustration of the changes in blood glucose over time following a high and low GI carbohydrate.