Is the glycemic index useful for controlling blood sugar if you have diabetes?

Answers from M. Regina Castro, M.D.

Some people with diabetes use the glycemic index (GI) as a guide in selecting foods for meal planning. The glycemic index classifies carbohydrate-containing foods according to their potential to raise your blood sugar level. Foods with a high glycemic index value tend to raise your blood sugar higher than do foods with a lower value.

The glycemic index may have some benefits, but may be problematic as well. Concerns include:

  • Single food items, rather than combinations of foods, can impact blood sugar differently
  • Doesn't consider all variables that affect blood sugar, such as how food is prepared or how much is eaten
  • Only includes foods that contain carbohydrates
  • Doesn't rank foods based on nutrient content — foods with a low GI ranking may be high in calories, sugar or saturated fat

It can be difficult to follow the glycemic index. For one thing, there is no standard for what is considered low, moderate and high glycemic foods. Packaged foods don't list their GI ranking on the label, and it can be hard to estimate what it might be.

Basic principles of healthy eating, portion control and counting carbohydrates are all ways to help you better manage and control your blood sugar. If you're interested in learning more, talk to a registered dietitian. He or she can help you make healthy changes in your eating habits for improved blood sugar control.


M. Regina Castro, M.D.

April 11, 2015