Glycemic Index – tool or toy?

The glycemic index has fascinated the medical community for almost 40 years and after all this time, I’m not certain we are of one mind about how to use it or even its value.

Two U of Toronto physicians, in an attempt to better treat their patients with Type 1 diabetes, came up with the idea of studying individual food’s influence on blood sugar.

Prior to their work, we thought simple carbohydrates raise blood sugar quickly and predictably. And, we assumed all complex carbohydrates acted alike and raised blood sugar more slowly. We stuck with that theory until specific foods were tested.

Diabetic or not, none of us wants a rapid rise in blood sugar.

Briefly, the glycemic index (GI) scale (0-100) is a reflection of the body’s response to one specific food as measured against the body’s response to glucose.

Today, one sees lists of high-, moderate- and low-glycemic index foods. Theoretically, these lists should be helpful for you when selecting carbohydrate-containing food. Pretzels are in the “high” category which means it will raise your blood sugar faster than ice cream (moderate category) – surprising and probably not all that helpful.

But it gets more confusing. Many variables alter a food’s glycemic index: ripeness, food preparation method, cooking time. Pasta for example cooked al dente has a lower value than pasta cooked longer.

Fat eaten along with a carb-containing food lowers the index. Ditto fiber, ditto acid (vinegar or lemon juice).  Variety of the fruit or vegetable?  Sure, GI changes with produce variety too.

So, while some professionals put great faith in GI lists and now “glycemic load”, I think it makes choosing foods more complicated than necessary. Let’s go back to the basics – limit your processed or “manufactured” food.

And don’t eat so much to be well,





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