Understanding how a food will affect your blood sugar level is much more difficult than just reading the nutrition facts label. Different types of carbohydrates combined with the amount of fiber and protein in a food all affect the body in different ways.

The glycemic index (GI) is a measure of carbohydrate quality based on immediate effect on blood sugar levels. The higher the glycemic index value, the faster and stronger the food affects your blood sugar and insulin levels. The standard nutrition facts label is misleading because it assumes that all starchy foods produce the same effect on blood sugar levels.

The glycemic index of a food is measured by comparing a volunteer’s blood sugar levels after consuming 50 grams of that food, to their blood sugar levels after consuming 50 grams of pure glucose (the reference level, which equals 100). This is done several times on several different volunteers in order to come up with an average measurement for that food.

High GI = 70 or higher

Intermediate GI = 56-69

Low GI = 0-55

Examples:

White Rice = 87

Apple = 40

Almonds = 0

Brand-Miller, Jennie, Thomas M.S. Wolever, Kaye Foster-Powell, and Stephen Colagiuri. The New Glucose Revolution; The Authoritative Guide to The Glycemic Index. New York: Marlowe & Company, 2003

Willett, M.D. Walter C. (2001). Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. New York, NY: Fireside