The glycemic index classifies foods that contain carbohydrates according to their potential to raise blood sugar. Foods with high glycemic index values tend to raise blood sugar higher, faster and for a longer time than do foods with lower values.

Research shows that eating a lot of foods that are high on the glycemic index is linked to an increased risk of diabetes, high blood pressure and heart disease. However, studies do not consistently show that eating foods with lower glycemic index values is associated with a reduction in these risks. Some people who have diabetes use the glycemic index as a guide for selecting foods.

The glycemic index has benefits. But it poses some challenges too, such as:

• It doesn't show how single food items versus a combination of foods can affect blood sugar differently.
• It doesn't take into account everything that can affect blood sugar. For example, it doesn't consider how food is prepared or how much a person eats.
• It only measures foods that have a high amount of carbohydrates. It doesn't include foods that have low carbohydrates or no carbohydrates.
• It doesn't rank foods based on their nutrients. Foods with a low glycemic index ranking may be high in calories, sugar or saturated fat.

It also may be hard to follow the glycemic index. For example, packaged foods generally don't list the glycemic index value on the label. And it can be hard to estimate it.

Basic principles of healthy eating, portion control and counting carbohydrates are all reliable ways to help manage blood sugar. To learn more, talk to a registered dietitian. A dietitian can help you make healthy changes in your diet for better blood sugar control.