What is the Glycemic Index?
Glycemic index (G.I.) is a measure of how fast a particular food releases its “sugar” into the blood stream. Sugars come in two forms: the simple sugars which are processed and enter the blood stream quickly, and the other form called “complex” which are found in whole unprocessed foods. The difference is the fiber content. In whole foods the sugars are wrapped in fiber that takes time to digest and so the sugars are released very slowly. A good example of this is an apple. An apple tastes sweet but the sugar enters the blood stream very slowly because the fiber in an apple takes a long time to break down. The opposite would be bread. Even though bread may contain some fiber the type of sugar it contains is easily and quickly released and causes your blood sugar to rise really fast. So even though the bread doesn't taste sweet it is a higher sugar food compared to an apple.
It is these rapid rises in blood sugar that stimulate a rapid aggressive spike in insulin. Insulin is a real trouble-maker. We need insulin to live but the least amount of insulin we can make on a daily basis then the longer we will live and the healthier we will be. Insulin is secreted when we eat high glycemic foods that spike our blood sugar. If you only remember ONE thing today then remember THIS: insulin tells our body to STOP BURNING FAT. Yikes !!! When insulin is elevated on a regular basis it causes many problems: diabetes, vascular disease, rapid aging, and increased fat storage. No thanks. By selecting foods that have a lower glycemic index we are eating foods that digest more slowly and cause a slow gradual release of sugar over a longer period of time. This results in a much lower total insulin response, and avoids the crash associated with low blood sugar (hypoglycemic episodes) after a sugar rush.
The glycemic index is based on a rating scale from 0 to 100 with the “100” representing the effect pure glucose has on the body. Kellogg ® corn flakes for example have a very high GI at 92 because processed corn flakes without corn’s natural fiber turn into sugar almost instantly in the body. An apple has sugars which make it taste sweet but its Glycemic Index is low at 35 due to all the fabulous healthy “fiber” that is bound to the sugars making the process of releasing them a slow digestive process. Any food with high fiber count (fresh fruits and vegetables) will tend to have a nice low G.I. (Glycemic Index). A banana has some fiber but less than an apple and so its glycemic index is higher at 52. So the take home message is that eating any food with a higher fiber content will decrease its G.I. which is good.
The other issue with glycemic index is that the absorption of sugar from foods will be slowed down when consumed with fat or protein. So eating some chicken which has fat and protein in combination with rice or potato will lower the overall glycemic effect by slowing the absorption of the sugar. As far as the glycemic index is concerned, eating carbohydrates (sugars) of any kind is best done in combination with protein and fat to reduce glycemic effect.
LOW: A Glycemic Index rating of 55 and below is considered low (desirable).
- These foods are typically whole unprocessed foods such as vegetables, fruit, beans, nuts and seeds.
MODERATE: is between 55 to 70.
- Some foods in this category can be in the diet but keep them to minimum as treats and not as regular staples that you eat daily.
- Examples: popcorn, canned fruit, long grain rice, cornmeal, honey, Snickers Bar
HIGH: a high glycemic index is anything over 70, try to avoid this as much as possible.
- These foods are usually things like wheat of any kind, crackers, cookies, muffins, rolls, cake pasta of any kind, white rice, and potato.
- Also many processed foods fall into this category.
Glycemic Index of Common Foods
In general the lower the glycemic response the better the quality of food
Poptarts 70 (high)
Rice Krispies 82 (high)
Waffles (Aunt Jemima) 76 (high)
Wonder Bread (white) 73 (high)
Shredded Wheat Cereal 83 (high)
English Muffin 77 (high)
Dates 103 (high)
Watermelon 72 (high)
Baked Potato 85 (high)
Chips, potato 75 (high)
Donut 76 (high)
French Baguette 95 (high)
Millet 71 (high)
Rice Cakes 77 (high)
Brown Rice 55 (med) - avoid white, sticky or Jasmine rice
Bran Muffins 60 (med)
Raisins 64 (med)
Popcorn 55 (med)
Muesli Cereal 56 (med)
Sweet Potato 54 (low)
Bananas 51 (low)
Cherries 22 (low)
Apples 35 (low)
Apple Juice 41 (low)
Orange 42 (low)
Soy Milk 44 (low)
Peanuts 37 (low)
Lentil Soup 44 (low)
Kidney Bean 29 (low)
Black Beans 48 (low)
Butter Beans 31 (low)
Chickpeas 33 (low)
Navy Beans 38 (low)
Carrots, cooked 39 (low)
Broccoli 15 (low)
Cucumber 15 (low)
Lettuce, all varieties 15 (low)
Spinach 15 (low)
Avocado, Bok choy 0 (low)
Artichokes, canbbage 0 (low)
Celery 0 (low)
References: For more information read the book: The New Glucose Revolution: Complete Guide To Glycemic Index Values by Jennie Brand-Miller.
