Glycemic Index
PROBLEM: High-Glycemic Foods
Many Americans are unintentionally eating large quantities of high-glycemic food without even knowing it is unhealthy. They start their days with supposedly healthy choices such as cold cereal, orange juice, and white toast, and then wonder why they are starving by lunchtime. The problem is, low-fat doesn’t always equal low-glycemic, and it has somehow become accepted that low-fat food equals a low-fat body.
The glycemic index forces us to acknowledge that the food we eat is more complicated than that.
Dr. David J. Jenkins introduced the glycemic index to the world in 1981. It ranks food on a scale of 0–100, based on how fast carbohydrates break down into glucose and enter the bloodstream.1 Foods that break down more slowly have a lower GI score, and foods that break down more quickly have a higher GI score. A score of 55 and below is considered low GI, 56–69 is medium, and 70 and above is high.
Foods that are digested quickly cause your blood sugar to rise sharply, only to come crashing down. If you’ve ever eaten a pastry for breakfast only to feel drained and hungry for more sugar in only a couple of hours, then you are familiar with this feeling. These high-glycemic foods are not satisfying in the long-term, even though they may provide a temporary blood sugar spike. Throughout the day, you consume more and more food, and gain the weight to prove it.
Just as relevant as the glycemic index is the glycemic load (GL) of your foods. Take the grams of carbohydrates in a food, multiply it by the glycemic index of the food, and then divide that number by 100. The glycemic load gives you a better idea of the actual impact the food has on your body. Though carrots have a medium glycemic index of 49, their glycemic load per serving is very low, at 2.9. This means that eating a serving of carrots will not spike your blood sugar.2 This scale looks a little different from the glycemic index: a score of 10 or less is considered low, 11–19 is medium, and 20 or above is high.
The food pyramid that most of us grew up with is inaccurate. We should not be consuming 8–11 servings of what we once believed to be healthy grains—even though they are often low in fat, these are usually just highly-processed products made with refined flour that will spike your blood sugar. High GI and high GL diets could be associated with an increased risk of diabetes among adults.3 That in itself should be enough of a motivator to check the glycemic index of your meals. Also consider that in one study, participants moving to a low-glycemic diet reduced their risk factors for coronary heart disease (CHD).4
SOLUTION: Switching to Low-Glycemic Foods
Start looking closely at your meals. Keep track of what you’re eating, and start checking where food falls on the glycemic index. Try the GI Database at http://www.glycemicindex.com/ to get an idea of how you’re doing. You may find you can substitute some of your favorite high-glycemic foods for low-glycemic alternatives. Try replacing white bread with pumpernickel, or instant oatmeal for slow-cooked oats.
Almost all food has a lower glycemic index in its raw form than when it is cooked, because the starches in raw food are more difficult to digest. In general, the more processed a food is, the higher its GI will be, and the closer it is to its natural form, the lower its GI will be. Choose raw, unprocessed fruits and vegetables whenever possible. Foods with higher fiber content will also tend to have a lower glycemic index.
When planning your meals, it’s important to keep a balance. Though low-glycemic foods are ideal, keep in mind your body’s need for a variety of nutrients. Don’t try to eat the same three foods every day just because they are the lowest on the glycemic index. You’ll only be frustrated, and you won’t be doing your body any good. Get your carbohydrates from a variety of sources, and don’t forget to have a salad now and then. Most vegetables are low-glycemic (except white potatoes), so stock up in the produce section. And remember that moderation is important: it’s ok to occasionally have a bagel if you really want one, but don’t count on bagels every morning as part of a nutritious, satisfying breakfast.
Examples of Foods to Mostly Avoid
Food |
Glycemic Index |
Glycemic Load |
Corn flakes |
92 |
24 |
Bagel, white |
72 |
25 |
Rice, white |
72 |
30 |
Rice, Jasmine |
109 |
46 |
Raisins |
64 |
28 |
Baked potato |
85 |
26 |
Angel food cake |
67 |
19 |
Jelly beans |
78 |
22 |
Popcorn |
72 |
24 |
Examples of Foods to Eat in Moderation
Food |
Glycemic Index |
Glycemic Load |
Oatmeal, rolled oats |
58 |
13 |
Macaroni |
47 |
23 |
Beans, black-eyed |
42 |
13 |
Sweet potato |
61 |
17 |
Couscous, boiled |
65 |
23 |
Corn, sweet |
54 |
9 |
Barley, cracked |
66 |
21 |
Examples of Foods to Eat Frequently
Food |
Glycemic Index |
Glycemic Load |
Apple |
38 |
6 |
Peach |
28 |
4 |
Beans, black |
20 |
5 |
Lentils |
29 |
5 |
Pumpernickel bread |
41 |
5 |
Oat bran bread |
47 |
9 |
Yogurt, low fat |
31 |
9 |
Almonds |
0 |
0 |
Hazelnuts |
0 |
0 |
For more information about how to use the glycemic index in your diet, go to Ray Strand’s website, http://www.releasingfat.com/.
1 Ray D. Strand, MD, Healthy for Life, (Rapid City, SD: Real Life Press, 2005).
2 Ibid.
3 Barclay, A.W., Petocz, P., Millan-Price, J., Flood, V.M., Prvan, T.,Mitchell, P., and Brand-Miller, J.C., “Glycemic index, glycemic load, and chronic disease risk–a meta-analysis of observational studies,” Am. J. Clin. Nutr. 87, no. 3, pg. 627–637.
4 David J.A. Jenkins et al., “Effect of a Low–Glycemic Index or a High–Cereal Fiber Diet on Type 2 Diabetes,” Journal of the American Medical Association 300, no. 23, http://jama.ama-assn.org/cgi/content/full/300/23/2742 (accessed November 15, 2010).
