The glycemic index is a number assigned to foods based on how they raise blood glucose values. Glucose is the chemical name of the sugar molecules in blood. All the carbohydrates (carbs), starches, and sugars that a person eats are digested or changed into glucose in the body. The amount of glucose in the blood at any given time is called blood glucose.

People with diabetes know that managing glucose levels is an important part of a healthy diet. Following the glycemic index can help.

The glycemic index is a measure of how many carbs a food has. Each food is measured by how much it raises blood glucose levels compared to a reference food—usually glucose or white bread. A food with a high glycemic index raises blood glucose levels more than a food with a low glycemic index.

Finding out the glycemic index of a food is not as easy as it sounds. There are many factors that affect it, such as ripeness. For example, ripe bananas have a higher glycemic index than unripe. This is because sugar is produced as fruit ripens, making it sweeter. Other factors may be how a food is cooked or what else is eaten with it. Most often, foods that are high in fiber have a lower glycemic index, and foods that are highly processed have a higher glycemic index.

Here are how some common foods compare:

Counting Carbs Instead

Most people with diabetes manage blood glucose by carb counting. This is done along with medicine and exercise. Monitoring the glycemic index may help even more. For instance, knowing how a person responds to high or low glycemic index foods can help that person plan their carb intake and avoid big changes in blood glucose levels. Spreading out carb intake over the course of the day can also help keep glucose levels steady.