The Glycemic Index and Diabetes  

The glycemic index indicates the after-meal response your body has to a particular food compared to a standard amount of glucose. If that sounds complicated — it is! Many factors come into play, including your age and activity level, the amount of fiber and fat in the particular food, how refined (processed) the food is, what else was eaten with the food, what the composition of the food is in terms of carb, protein and fat, how the food was cooked, and how quickly your body digests the food (which varies from person to person).

In general, fiber-rich foods are often the same foods that are thought to be low glycemic foods and seem to have less effect on blood glucose. Sucrose (table sugar) also has a lower effect on blood glucose than some starches, such as potatoes. There are lists of such "high" and "low" glycemic index foods.

Health professionals agree that the more complex a meal plan is, the less likely people are to follow it. The glycemic index is a fairly complex meal planning tool, and the fact that people's blood glucose can react differently to so-called "low" and "high" glycemic index foods has limited the usefulness of the index in teaching patients with diabetes how to manage their food intake to keep their blood glucose under control. However, the glycemic index may be be used as an additional tool together with a patient's current meal planning system. Registered dietitians often encourage patients to determine their own individual glycemic index of foods based on how their blood glucose responds to the various meals and snacks they tend to eat.

Most dietitians and other healthcare professionals working with patients prefer to talk in terms of the number of grams of carbohydrate in a food, rather than the "glycemic index" of a food. Carbohydrate has the greatest effect on blood glucose, so in general two foods that have the same number of grams of carbohydrate in them will have a similar effect on your blood glucose level. Your dietitian works with you to determine — based on your weight, how active you are, and other factors — how many grams of carbohydrate you can eat at each meal and snack to keep your blood glucose under control. This type of meal planning is simpler to use, offers greater flexibility, and enables many people to manage their diabetes successfully.

See also:
What is carbohydrate counting?
How does fiber affect blood glucose levels?
How much carbohydrate should I be eating in a day?