Using glycemic index in meal planning
One of the main drawbacks to relying on the glycemic index is that the methods used to determine the glycemic index of foods are not standardized. Some research uses blood samples taken from a vein, while other research uses blood samples taken from capillaries; blood glucose levels in venous samples can vary more than in capillary samples. Some research uses white bread as the reference food, while other research uses glucose. These different methods can produce different results.
Among the general population, the glycemic response to even similar foods can vary immensely, and currently only a relatively small number of foods have been tested. Furthermore, one brand of whole wheat bread may very well have a substantially different glycemic index than its competitor, and a shopper would have no way of knowing it unless both were tested. Currently, some Australian companies are testing their food products for glycemic index and adding that information to labels of packaged goods. This may prove to be a future trend in food labeling.
Until this trend crosses the globe, however, how can one use this potentially powerful tool in meal planning? First, remember that the basics of good nutrition still apply. Foods that are mostly fat or protein have an undetectable glycemic index and may even slightly reduce the glycemic index of carbohydrate-containing meals. However, this doesn’t mean they have no potentially negative health effects. Fat is a very dense source of calories, and even healthy fats (and protein) can contribute to weight gain when consumed in excess. In addition, saturated and trans fats have negative effects on heart health and should be eaten only in moderation. Second, according to Brand-Miller, “If you can cook something more quickly, you can digest it more quickly.” This means that choosing the least processed foods will help reduce the glycemic index of your overall diet.
Consult the sidebar “High, Low, and Intermediate” for a list of low-glycemic-index foods and incorporate them into as many meals as possible, especially breakfast, which tends to raise blood glucose higher than other meals. At the same time, go easy on the highest-glycemic-index foods like most breakfast cereals (even many whole-grain varieties have high glycemic index values) and potatoes. (Check out “Glycemic Index and Glycemic Load of Select Foods” to learn more about which foods to eat in moderation.) Limiting all sources of carbohydrate to about 45% of your daily calories (but not less than 45%) will decrease the glycemic load of your diet while still providing adequate energy and nutrients. Also, since the vast majority of fruits and vegetables have a low glycemic index, this is yet another reason to eat your fruits and vegetables every day. (For more tips on planning meals using the glycemic index, see “Tips For Meal Planning.”) You can use your daily blood glucose monitoring results to determine your individual glycemic response to foods and adjust your diet accordingly. Last but not least, get moving. Physically fit people have a lower glycemic response to foods than sedentary people.
Using the glycemic index and other meal-planning tools may not be enough for everyone with diabetes to stay within target blood glucose ranges after meals. If you are particularly prone to post-meal high blood glucose, you may want to consult your physician about medicines that specifically target after-meal blood glucose levels.