The glycemic index (GI) is a number that indicates how quickly a particular food will raise the blood sugar.
The higher the number, the higher the blood sugar response. Not all of these foods taste “sweet.” Even some complex carbohydrates are broken down quickly into sugar in the body, particularly potatoes or grains that have been ground into flour.
Foods with a high glycemic index signal the body to produce large amounts of insulin, a hormone that carries blood sugar into the cells to be used for energy or stored for later use. After eating high GI foods, large amounts of insulin may be released causing a rapid drop in blood sugar (called “reactive hypoglycemia”) that can lead to shakiness, “spaciness,” or fatigue several hours after eating, as well as an increase in appetite.
High glycemic index foods should be avoided by people who are trying to lose weight, people who have diabetes or may be at high risk for diabetes, and people who have “hypoglycemia” symptoms. If you have any of these conditions, try to avoid foods with a high glycemic index and emphasize foods with GI below 45.
A more sophisticated measure of the glycemic effects of foods is called “glycemic load.”
Glycemic load considers the actual amount of carbohydrates present in a typical serving of a food. A glycemic load number below 10 is considered low, 11-19 medium, and 20 or above is high. For example, while watermelon has a high glycemic index number of 72, its glycemic load number is only 7.21 because of the limited amount of carbs in a serving.
Some foods have low impact on the blood sugar despite their high glycemic index when they are eaten in normal portion sizes. Carrots, for instance, have a high glycemic index, but it takes 6.6 cups of carrots to deliver the same amount of carbohydrate that is found in 1 cup of cooked spaghetti. Since most people do not eat that many carrots at a sitting, carrots do not tend to have a big impact on blood sugar. The Glycemic Load takes the amount of carbs in a typical serving into account along with the glycemic index and can give a more balanced view of how eating typical servings of a particular food will affect blood sugar.
Some basic tips to keep the glycemic load of the diet down include:
- Eat whole grains (i.e., where you can see the grains in your bowl, not where they have been ground into flour.) Limit processed grains.
- Pass on the potatoes and bananas.
- Bring on the beans. Beans are a great source of protein as well as a good source of slowly digested carbohydrates.
For more information, see http://www.mendosa.com/gi.htm or read The GI Diet by Gallop or The New Glucose Revolution by Wolliver. Thanks to the Institute of Functional Medicine.
Glycemic Index and Glycemic Load of Certain Foods
|Glycemic Index||Carbs (grams per serving)||Glycemic Load per serving|
|High||70 or more||20|
|Medium||50-69||11 to 19|
|Low||49 or less||10 or less|
|Apple, 1 average||38||16||6|
|Banana, 1 whole, ripe||51||26.5||14|
|Orange, 1 whole||42||12||5|
|Raisins, ½ cup||64||44||28|
|Broccoli, ½ cup steamed||6||2||1|
|Carrots, 1 cup raw||47||6||3|
|Corn on the cob, 1 ear||53||29||15|
|Green beans, ½ cup||28||5||1|
|Baked potato, white||85||30.5||26|
|Spinach, ½ cup steamed||6||3.5||1|
|Tomatoes, 1 cup raw||61||28||17|
|Pumpernickel bread, 1 slice||41||26||4.5|
|White bread, 1 slice||70||25||8.4|
|French bread, 1 slice||95||64||29.5|
|Whole wheat pita||57||64||17|
|Bran muffin 1 medium||60||113||30|
|Corn Bread 1 slice||110||60||30.8|
|Oatmeal 1 cup||58||234||12.8|
|Oatmeal, instant 1 cup||65||234||13.7|
|Corn Flakes 1 cup||92||28||21.1|
|Kellogg’s Special K 1 cup||69||31||14.5|
|Grape Nuts ½ cup||75||58||31.5|
|Popcorn 1 cup||55||8||2.8|
|Rice white, 1 cup cooked||64||36||23|
|Rice brown, 1 cup cooked||55||33||18|
|Baked beans 1 cup||48||253||18.2|
|Chickpeas, boiled 1 cup||31||240||13.3|
|Kidney beans 1 cup||27||256||7|
|Lentils 1 cup||29||198||7|
|Soy beans 1 cup||20||172||1.4|
|Pinto beans 1 cup||39||171||11.7|
|Chana Dal||8 – 11||3.9||2.4|
|Apple Juice 8 oz||40||30||12|
|Pepsi 8 oz||58||25||15|
|Tomato juice, ½ cup||38||10||4|