By Annette R. Karnash, R.N., M.N.
The glycemic index in a food is determined by the rise in blood glucose during the 2 hours after its ingestion compared with the glucose response to an equal amount of carbohydrate in standard foods like white bread, which has a glycemic index of 100. Foods higher than 100 (instant rice) cause a faster and higher rise in blood glucose than white bread. Kidney beans (a low glycemic food of only 38) increases blood glucose by only about 1/3 as much as an equal amount of white bread.
Rather than the glucose index response of the body to each carbohydrate, the individual with diabetes should determine the amount of carbohydrates consumed daily. Nutritious foods such as corn, carrots and raisins have a high glycemic index, but should not be eliminated. Fruits and whole grain breads are better carbohydrate sources than candy or white bread. Because those individuals with diabetes need to control their blood glucose, it might seem like the glycemic index would be an important tool in choosing food. However, the glycemic index is impractical because it is not listed on food labels, it rates only single foods eaten individually and the effect of a food on blood glucose levels vary depending upon whether a food is cooked or eaten in combination with other foods and what the blood glucose was before eating.
