Glycemic index and diabetes
Glycemic index (GI) is a measure of how quickly a food can make your blood sugar (glucose) rise. Only foods that contain carbohydrates have a GI. Foods such as oils, fats, and meats do not have a GI, though in people with diabetes, they can affect the blood sugar.
In general, low GI foods increase glucose slowly in your body. Foods with a high GI increase blood glucose quickly.
If you have diabetes, high GI foods can make it harder to control your blood sugar.
Diabetes
Diabetes is a long-term (chronic) disease in which the body cannot regulate the amount of sugar in the blood.

Information
Not all carbohydrates work the same in the body. Some trigger a quick spike in blood sugar, while others work more slowly, avoiding large or rapid rises in blood sugar. The glycemic index addresses these differences by assigning a number to foods that reflects how quickly they increase blood glucose compared to pure glucose (sugar).
The GI scale goes from 0 to 100. Pure glucose has the highest GI and is given a value of 100.
Eating low GI foods can help you gain tighter control over your blood sugar. Paying attention to the GI of foods can be another tool to help manage your diabetes, along with carbohydrate counting. Following a low-GI diet also may help with weight loss.
Carbohydrate counting
Many foods contain carbohydrates (carbs), including:Fruit and fruit juiceCereal, bread, pasta, and riceMilk and milk products, soy milkBeans, legumes...

Glycemic Index of Certain Foods
Low GI foods (0 to 55):
- Bulgur, barley
- Pasta, parboiled (converted) rice
- Quinoa
- High-fiber bran cereal
- Oatmeal, steel-cut or rolled
- Carrots, non-starchy vegetables, greens
- Apples, oranges, grapefruit, and many other fruits
- Most nuts, legumes, and beans
- Milk and yogurt
Moderate GI foods (56 to 69):
- Pita bread, rye bread
- Couscous
- Brown rice
- Raisins
- Honey
- Pineapple
High GI foods (70 and higher):
- White bread and bagels
- Most processed cereals and instant oatmeal, including bran flakes
- Most snack foods
- Potatoes
- White rice
- Sugar
- Watermelon
Meal Planning with the Glycemic Index
When planning your meals:
- Choose foods that have a low to medium GI.
- When eating a high GI food, combine it with low GI foods to balance the effect on your glucose levels. The GI of a food, and its impact on people with diabetes may change when you combine it with other foods.
The GI of a food is affected by certain factors, such as the ripeness of a piece of fruit. So, you need to think about more than the GI of a food when making healthy choices. When choosing meals, it's a good idea to keep these issues in mind.
- Portion size still matters because calories still matter, and so does the amount of carbohydrates. You need to keep an eye on the portion size and number of carbohydrates in the meal you are having, even if it has low GI foods.
- In general, processed foods have a higher GI. For example, fruit juice and instant potatoes have a higher GI than whole fruit and whole baked potatoes.
- Cooking can affect the GI of a food. For example, al dente pasta has lower GI than soft-cooked pasta.
- Foods higher in fat or fiber tend to have a lower GI.
- Certain foods from the same class of foods can have different GI values. For example, converted long-grain white rice has a lower GI than brown rice. And short-grain white rice has a higher GI than brown rice. Likewise, quick oats or grits have a high GI but whole oats and whole-grain breakfast cereals have a lower GI.
- Choose a variety of healthy foods keeping in mind the nutritional value of the whole meal as well as the GI of foods.
- Some high GI foods are high in nutrients. So balance these with lower GI foods.
For many people with diabetes, carbohydrate counting, or carb counting, helps limit carbohydrates to a healthy amount. Carb counting along with choosing healthy foods and maintaining a healthy weight may be enough to regulate diabetes and lower the risk for complications. But if you have trouble regulating your blood sugar or want tighter control, you should talk with your health care provider about using the glycemic index as part of your action plan.
Complications
Diabetes makes your blood sugar higher than normal. After many years, too much sugar in the blood can cause problems in your body. It can harm your...

References
American Diabetes Association Professional Practice Committee. 5. Facilitating Positive Health Behaviors and Well-being to Improve Health Outcomes: Standards of Care in Diabetes-2024. Diabetes Care. 2024;47(Suppl 1):S77-S110. PMID: 38078584 pubmed.ncbi.nlm.nih.gov/38078584/.
MacLeod J, Franz MJ, Handu D, et al. Academy of Nutrition and Dietetics Nutrition practice guideline for type 1 and type 2 diabetes in adults: nutrition intervention evidence reviews and recommendations. J Acad Nutr Diet. 2017;117(10)1637-1658. PMID: 28527747 pubmed.ncbi.nlm.nih.gov/28527747/.
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Complex carbohydrates - illustration
Complex carbohydrates are made up of sugar molecules that are strung together in long, complex chains. Complex carbohydrates are found in foods such as peas, beans, whole grains, and vegetables. Both simple and complex carbohydrates are turned to glucose (blood sugar) in the body and are used as energy. Glucose is used in the cells of the body and in the brain. Any unused glucose is stored in the liver and muscles as glycogen for use later. Complex carbohydrate foods provide vitamins, minerals, and fiber that are important to the health of an individual. The majority of carbohydrates should come from complex carbohydrates (starches) and naturally occurring sugars, rather than processed or refined sugars, which do not have the vitamins, minerals, and fiber found in complex carbohydrates. Refined sugars are often called empty calories because they have little to no nutritional value.
Complex carbohydrates
illustration
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Simple carbohydrates - illustration
Simple carbohydrates are broken down quickly by the body to be used as energy. Simple carbohydrates are found naturally in foods such as fruits, milk, and milk products. They are also found in processed and refined sugars such as candy, table sugar, syrups, and soft drinks. The majority of carbohydrate intake should come from complex carbohydrates (starches) and naturally occurring sugars rather than processed or refined sugars.
Simple carbohydrates
illustration
-
Complex carbohydrates - illustration
Complex carbohydrates are made up of sugar molecules that are strung together in long, complex chains. Complex carbohydrates are found in foods such as peas, beans, whole grains, and vegetables. Both simple and complex carbohydrates are turned to glucose (blood sugar) in the body and are used as energy. Glucose is used in the cells of the body and in the brain. Any unused glucose is stored in the liver and muscles as glycogen for use later. Complex carbohydrate foods provide vitamins, minerals, and fiber that are important to the health of an individual. The majority of carbohydrates should come from complex carbohydrates (starches) and naturally occurring sugars, rather than processed or refined sugars, which do not have the vitamins, minerals, and fiber found in complex carbohydrates. Refined sugars are often called empty calories because they have little to no nutritional value.
Complex carbohydrates
illustration
-
Simple carbohydrates - illustration
Simple carbohydrates are broken down quickly by the body to be used as energy. Simple carbohydrates are found naturally in foods such as fruits, milk, and milk products. They are also found in processed and refined sugars such as candy, table sugar, syrups, and soft drinks. The majority of carbohydrate intake should come from complex carbohydrates (starches) and naturally occurring sugars rather than processed or refined sugars.
Simple carbohydrates
illustration
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Review Date: 10/11/2024
Reviewed By: Frank D. Brodkey, MD, FCCM, Associate Professor, Section of Pulmonary and Critical Care Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
