Meal Planning by the Numbers
The glycemic index can help you plan diabetes-friendly meals—but only if used properly
Publish Date: August 2007
Sometimes a new way of thinking about food catches fire in the public’s imagination, suggesting a quick-fix solution to weight loss or blood glucose control. One such concept today is the glycemic index (GI).
The GI is a scale that ranks carbohydrate-rich food by how much it raises blood glucose compared to glucose or white bread.
Planning meals based on a food’s impact on blood glucose levels may seem tailor-made for people with diabetes. But is the GI the magic bullet we’ve all been waiting for to help us streamline the way we manage our diabetes? It can be a helpful tool, say the experts at Johns Hopkins, but only if used properly.
Glycemic index is the number assigned to a carbohydrate-containing food. A GI of 55 or less ranks as low, a GI of 56 to 69 is medium and a GI of 70 or more ranks as high. (Common foods and their GI value are listed at the end of this article.)
Know the proven benefits of a low-GI diet
Despite the recent popularity of the GI among the general public, it’s taken longer for the medical community to agree on whether this concept helps people with diabetes control their blood glucose. In 2003, an article published in the journal “Diabetes Care” examined data from 14 studies that compared low-GI and high-GI diets for their effects on after-meal glucose levels. The authors determined that people with diabetes might receive a small benefit by choosing lower-GI foods over medium- or high-GI foods.
The American Diabetes Association states that using the GI to plan meals may provide modest help in controlling blood glucose levels, but that total carbohydrate grams consumed is more important.
Factors that affect GI
Do the blood glucose control and other potential benefits of a low-GI meal plan mean you should switch to a diet composed solely of low-GI foods? It’s not that simple. The GI should not be your only guide to meal planning. This is because a food’s GI value depends on several factors, among them:
Fiber content. Foods that are less processed or naturally high in fiber or both slow the release of sugar molecules into the bloodstream.
Ripeness. Riper fruits and vegetables tend to have more sugar than unripe ones. The riper the fruit, the higher its GI.
Fat content. The more fat or acid a food contains, the slower its carbohydrates are converted to sugar and absorbed into the bloodstream.
Learn the basic characteristics that determine whether a food has a low-, medium- or high-GI value and what happens to your blood glucose levels when you eat a particular food. The GI of the carbohydrate foods you eat is just one element in planning a balanced diet. Work with a diabetes educator or dietitian to develop a healthy diabetes-friendly meal plan that suits your needs and helps keep your blood glucose levels within your target range.
What are the glycemic indexes of your favorite carbohydrates?
Low-GI carbs (up to 55): milk, apples, grapes, bananas, pears, brown rice, lentils, yams, peas, nuts
High-GI carbs (70 or higher): watermelon, dried dates, white bread, baked potatoes, french fries, refined cereal products (Cheerios®, corn flakes, Rice Krispies®), Coca-Cola® soda, jelly beans, cooked couscous
For a more in-depth listing of foods and their glycemic indexes, go to www.glycemicindex.com.
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