What is Glycemic Index?

Author: Eric Knight, CPT(Canfit Pro), H. Ba. Kin
While many of you are trying to determine what to eat before and after a workout, you may have heard people talking about simple and complex carbohydrates. It is known that complex carbohydrates (starches like pastas, breads and grains) provide long lasting energy while simple carbohydrates (sugar in sweets and fruits) provided us with fast but short duration energy. Athletes use these guidelines to determine what to eat and when in order to have optimal energy for workouts. Lately, a new categorizing strategy has been developed to simplify the energy we get from foods, called the Glycemic Index.

The glycemic index refers to a food's ability to contribute to glucose levels in the blood stream. A food's glycemic index is determined by fibre content, fat additives, and the food's preparation method. It was first developed for diabetes patients to help control their blood glucose levels. High glycemic index carbohydrates swiftly provide our blood streams with glucose. These are best eaten after a workout to quickly replenish the body with energy. Low glycemic index carbohydrates slowly provide the blood stream with glucose. These foods are best eaten before a workout since it will provide our bodies with the energy needed to perform the activity.
Below is a chart depicting the high and low glycemic index carbohydrates:
Food
Glycemic Index
Gatorade
91
Baked Potato
85
Corn Flakes
84
Rice Cakes
82
Jelly Beans
80
Cheerios
74
Bagel
72
Bran Muffin
60
Orange juice
57
Potato, boiled
56
White Rice
56
Apple
36
Power Bar
30-35
Fruit Yogurt, low fat
33
Milk, skim
31
Banana
30
Data from food companies and K. Foster-Powell and J. Brand Miller, 1995, "International tables of glycemic index," Am J Clin Nutr 62:871S-893S