What is Glycemic Index?
Watching your blood sugar is the central concern when managing your diet to control your diabetes. For this reason, carb counting is your most valuable tool. However, it need not be your only tool. For those willing to invest a bit of extra effort, the Glycemic Index (or GI) is a measurement of how much a particular food will raise your blood glucose levels. Food with a higher glycemic index raises glucose levels more than food with a lower GI. The glycemic index of a food is based how much it raises blood glucose levels as compmared to a reference food, such as white bread.
Estimating Glycemic Index
In short, not all carbohydrates are equal. Here are a couple of rules of thumb to help you estimate the relative glycemic index of a particular food.
- The riper the fruit or vegetable, the higher its glycemic index.
- The more the food has been processed, the higher its glycemic index. For example, fruit has a lower GI than fruit juice.
- The longer you cook a food (e.g. pasta), the higher its glycemic index.
While glycemic index is only measured for individual foods, the glycemic index of a food combination can be different from the GI of either of those foods individually. In practice, this means that if you are eating a food with a high GI, you can partially counteract its effects by combining it with a food that has a lower GI.
No Perfect System
Note that, while watching the glycemic index of the foods you eat is a handy tool for fine-tuning your diet, it should not replace carbohydrate counting. Note, too, that foods with a low glycemic index still raise your blood sugar—just not as much.
Finally, it’s not necessary to always eat foods with the lowest glycemic index possible. In some cases this can even be bad for your health, since healthier foods often have a higher glycemic index—for example, oatmeal’s GI is higher than chocolate’s. All of which is to say that no one rule—not carb-counting, not glycemic index, not medication—is “the right system” to control your diabetes. Over time, you and your doctor will, through trial and error, develop the system that best fits your health goals, your personal preferences, and your lifestyle.