Can Glycemic Index Help Control Blood Glucose?

Q: I've read a lot about the glycemic index. Can this help me control my blood glucose?

A: The glycemic index is a system that ranks carbohydrate-containing foods according to how much they cause blood glucose to rise up to two hours after eating, compared with the same amount of carbohydrates in either glucose or white bread. The premise is that foods with a high glycemic index may cause blood glucose to rise to a higher level than foods with a low glycemic index.

Unfortunately, this concept doesn't consider many other variables about food, such as the ripeness of the food (such as a banana), how much or little it is cooked (such as pasta), and the nonfood variables that affect blood glucose, such as what your blood glucose is when you eat, how much exercise you get, and more.

Several studies have found a small amount of improvement in blood glucose control and some reduction in postprandial (after-meal) glucose levels when individuals incorporated low-glycemic-index foods into their diets. Other studies suggest no significant difference. The American Diabetes Association recommends that the glycemic index may provide modest additional benefit over what you observe when you consider the total amount of carbohydrates you eat alone.

Jeannette Jordan, M.S., R.D., CDE, is the American Dietetic Association's national spokesperson for African-American nutrition issues and oversees nutrition education at the Medical University of South Carolina.