Table of ContentsView AllTable of ContentsDefinitionGI of Common FoodsMeasuring ValuesBenefitsShortcomingsGI vs. GLGL ValuesGL of Common FoodsTesting a Food’s Impact
Table of ContentsView All
View All
Table of Contents
Definition
GI of Common Foods
Measuring Values
Benefits
Shortcomings
GI vs. GL
GL Values
GL of Common Foods
Testing a Food’s Impact
The glycemic index (GI) is a relative ranking of how different carbohydrates affect blood sugar.When you havetype 2 diabetes, one of the best ways to control your glucose levels is to eat foods that don’t cause major blood sugar (glucose) spikes.
Knowing theglycemic indexof thecarbohydratesyou eat can help you fine-tune your meals to keep your blood sugar within a normal range. Foods with a higher GI value are more likely to spike your blood sugar than foods with a lower GI.
Charday Penn / Getty Images
What Is the Glycemic Index?
The GI is a rating system that ranks carbohydrates on a scale of 1 to 100 based on how much they raise blood sugar.
Processed foods such as candy, breads, cake, and cookies have a high GI, whilewhole foodssuch as unrefined grains, non-starchy vegetables, and fruits tend to have a lower GI.
Carbohydrates with a low GI value are digested, absorbed, and metabolized more slowly than their high-GI counterparts. They typically cause a lower and slower rise in blood glucose and, subsequently,insulinlevels as well.
Foods that are primarily fat or protein are not included in the index because they have a minimal impact on blood sugar levels.
Glycemic Index Chart for Common Foods
The GI values can be broken down into three ranges. Food with a low GI is a food that won’t raise your blood sugar as much as a food with a medium or high GI.
The following charts highlight low, medium, and high GI foods:.
How Glycemic Index Is Measured
Researchers measured blood sugar levels of healthy volunteers before and two-hours after eating 50 grams of the same digestible carbohydrate (the test food). The points were then plotted on a graph and researchers determined the area under the curve (AUC) of their glucose response.
At a separate date, the same 10 people consumed 50 grams of pure glucose (the reference food), and researchers again measured each person’s glucose response AUC two hours after consumption.
Ultimately, the GI value is the average person’s blood sugar response to a specific carbohydrate. Individual responses may vary based on other factors including other foods eaten in combination with the carbohydrate.
Since it’s the carbohydrates in food that raise blood sugar, understanding GI can help you figure out which foods are best for glucose management.
Among the benefits of following the GI list when planning your meals:
Critics of the GI system note it has several flaws that can make it an unreliable measurement. GI looks strictly at the carb count. Basing a diet around GI only means you would be ignoring a lot of other helpful information to determine the true health value of a food.
The GI index doesn’t take into account:
For example, eating an apple on its own may result in a different blood glucose response than if you ate it with some peanut butter. Protein and fat can delay carbohydrate metabolism and, therefore, result in a slower blood sugar rise.
Why are foods like meat and butter not on the glycemic index?The glycemic index (GI) is a measure of how much the carbohydrates in a food affect blood sugar. Since foods like meat and butter don’t contain carbohydrates, they are not included.
Why are foods like meat and butter not on the glycemic index?
The glycemic index (GI) is a measure of how much the carbohydrates in a food affect blood sugar. Since foods like meat and butter don’t contain carbohydrates, they are not included.
Glycemic Index vs. Glycemic Load
To counteract some of the issues with glycemic index, researchers developed the glycemic load (GL) measurement. Unlike GI, GL accounts for the quantity of the food being eaten.The main difference between GI and GL is:
For example, an apple has a GI of 40 and contains 15 grams of carbs. (40 x 15)/100 = 6, so the glycemic load of an apple is 6.
Glycemic Load Values
In theory, foods with a low GI would also have a low GL, but that isn’t always the case. Research from the International Carbohydrate Quality Consortium (ICQC) suggests that glycemic load is a more reliable indicator of how a particular carbohydrate affects blood sugar.
Like GI values, GL values can also be broken down into three ranges:
Some foods fall under the same category for both glycemic index and glycemic load. For example, apples andorangesare both low GI and low GL, while cornflakes and boiled potatoes have both high GI and high GL.
But for other foods, the glycemic index and glycemic load are different. For example, bananas have a low GI but a medium GL and dates have a low GI and a high GL.
A food that perhaps best highlights the difference between glycemic index and glycemic load is spaghetti. Both whole grain spaghetti and spaghetti made from white flour are considered low GI (48 and 49, respectively). However, whole wheat spaghetti has a medium GL (14) while regular, white flour spaghetti has a high GL (20).
Glycemic Load Chart for Common Foods
The following charts highlight low, medium, and high GL foods based on data from the Linus Pauling Institute at Oregon State University.
The Best Way to Test a Food’s Impact
The American Diabetes Association states that carbohydrate amount (grams of carbohydrates) and available insulin may be the most important factors influencing blood sugar response after eating and should be considered when developing an eating plan.
For most people, an ideal blood sugar result is less than 180mg/dL two hours after the start of a meal.If you are not sure of what your target blood sugar should be, discuss it with your physician.
A Word From VerywellPaying attention to the glycemic index of foods can be a useful method to help avoid sudden spikes in blood sugar. However, the glycemic index is not the be-all, end-all of blood sugar control, and it shouldn’t be your only tool for managing your blood sugar. You might try using the glycemic index along with lifestyle changes, like exercise and eating balanced meals, to find what works best for you.—ALLISON HERRIES, RDN, MEDICAL EXPERT BOARD
A Word From Verywell
Paying attention to the glycemic index of foods can be a useful method to help avoid sudden spikes in blood sugar. However, the glycemic index is not the be-all, end-all of blood sugar control, and it shouldn’t be your only tool for managing your blood sugar. You might try using the glycemic index along with lifestyle changes, like exercise and eating balanced meals, to find what works best for you.—ALLISON HERRIES, RDN, MEDICAL EXPERT BOARD
Paying attention to the glycemic index of foods can be a useful method to help avoid sudden spikes in blood sugar. However, the glycemic index is not the be-all, end-all of blood sugar control, and it shouldn’t be your only tool for managing your blood sugar. You might try using the glycemic index along with lifestyle changes, like exercise and eating balanced meals, to find what works best for you.
—ALLISON HERRIES, RDN, MEDICAL EXPERT BOARD
Summary
The glycemic index is a measure of how much carbohydrate-containing foods raise blood sugar. Research shows that eating a low glycemic diet can help you mange your blood sugar and weight.
A low GI is considered 55 or less. Some good food choices low on the glycemic index include most vegetables and fruits, nuts, minimally processed grains, and pasta (both regular and whole grain).
10 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Glycemic Index Foundation.Low GI explained.Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J.International tables of glycemic index and glycemic load values 2021: a systematic review.The American Journal of Clinical Nutrition. 2021;114(5):1625-1632. doi:10.1093/ajcn/nqab233The University of Sydney.About - glycemic index.Centers for Disease Control and Prevention.Diabetes meal planning.Willett W, Liu S.Carbohydrate quality and health: distilling simple truths from complexity.Am J Clin Nutr. 2019;110(4):803-804. doi:10.1093/ajcn/nqz215Augustin LSA, Kendall CWC, Jenkins DJA, et al.Glycemic index, glycemic load and glycemic response: An International Scientific Consensus Summit from the International Carbohydrate Quality Consortium (ICQC).Nutr Metab Cardiovasc Dis. 2015;25(9):795-815. doi:10.1016/j.numecd.2015.05.005Oregon State University: Linus Pauling Institute Micronutrient Information Center.Glycemic Index and Glycemic Load.American Diabetes Association.Carb counting and diabetes.American Diabetes Association.6. Glycemic targets: Standards of medical care in diabetes—2022.Diabetes Care. 2022;45(Supplement 1): S83–S96. doi:10.2337/dc22-S006Harvard Health Publishing.A good guide to good carbs: The glycemic index.Additional ReadingAmerican Diabetes Association. 5.Facilitating behavior change and well-being to improve health outcomes:standards of medical care in diabetes—2021.Dia Care. 2021;44(Supplement 1):S53-S72. doi:10.2337/dc21-S005Shukla A, Iliescu R, Thomas C, Aronne L.Food order has a significant impact on postprandial glucose and insulin levels. Diabetes Care. 2015; 38(7):e98-e99. doi:10.2337/dc15-0429
10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Glycemic Index Foundation.Low GI explained.Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J.International tables of glycemic index and glycemic load values 2021: a systematic review.The American Journal of Clinical Nutrition. 2021;114(5):1625-1632. doi:10.1093/ajcn/nqab233The University of Sydney.About - glycemic index.Centers for Disease Control and Prevention.Diabetes meal planning.Willett W, Liu S.Carbohydrate quality and health: distilling simple truths from complexity.Am J Clin Nutr. 2019;110(4):803-804. doi:10.1093/ajcn/nqz215Augustin LSA, Kendall CWC, Jenkins DJA, et al.Glycemic index, glycemic load and glycemic response: An International Scientific Consensus Summit from the International Carbohydrate Quality Consortium (ICQC).Nutr Metab Cardiovasc Dis. 2015;25(9):795-815. doi:10.1016/j.numecd.2015.05.005Oregon State University: Linus Pauling Institute Micronutrient Information Center.Glycemic Index and Glycemic Load.American Diabetes Association.Carb counting and diabetes.American Diabetes Association.6. Glycemic targets: Standards of medical care in diabetes—2022.Diabetes Care. 2022;45(Supplement 1): S83–S96. doi:10.2337/dc22-S006Harvard Health Publishing.A good guide to good carbs: The glycemic index.Additional ReadingAmerican Diabetes Association. 5.Facilitating behavior change and well-being to improve health outcomes:standards of medical care in diabetes—2021.Dia Care. 2021;44(Supplement 1):S53-S72. doi:10.2337/dc21-S005Shukla A, Iliescu R, Thomas C, Aronne L.Food order has a significant impact on postprandial glucose and insulin levels. Diabetes Care. 2015; 38(7):e98-e99. doi:10.2337/dc15-0429
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Glycemic Index Foundation.Low GI explained.Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J.International tables of glycemic index and glycemic load values 2021: a systematic review.The American Journal of Clinical Nutrition. 2021;114(5):1625-1632. doi:10.1093/ajcn/nqab233The University of Sydney.About - glycemic index.Centers for Disease Control and Prevention.Diabetes meal planning.Willett W, Liu S.Carbohydrate quality and health: distilling simple truths from complexity.Am J Clin Nutr. 2019;110(4):803-804. doi:10.1093/ajcn/nqz215Augustin LSA, Kendall CWC, Jenkins DJA, et al.Glycemic index, glycemic load and glycemic response: An International Scientific Consensus Summit from the International Carbohydrate Quality Consortium (ICQC).Nutr Metab Cardiovasc Dis. 2015;25(9):795-815. doi:10.1016/j.numecd.2015.05.005Oregon State University: Linus Pauling Institute Micronutrient Information Center.Glycemic Index and Glycemic Load.American Diabetes Association.Carb counting and diabetes.American Diabetes Association.6. Glycemic targets: Standards of medical care in diabetes—2022.Diabetes Care. 2022;45(Supplement 1): S83–S96. doi:10.2337/dc22-S006Harvard Health Publishing.A good guide to good carbs: The glycemic index.
Glycemic Index Foundation.Low GI explained.
Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J.International tables of glycemic index and glycemic load values 2021: a systematic review.The American Journal of Clinical Nutrition. 2021;114(5):1625-1632. doi:10.1093/ajcn/nqab233
The University of Sydney.About - glycemic index.
Centers for Disease Control and Prevention.Diabetes meal planning.
Willett W, Liu S.Carbohydrate quality and health: distilling simple truths from complexity.Am J Clin Nutr. 2019;110(4):803-804. doi:10.1093/ajcn/nqz215
Augustin LSA, Kendall CWC, Jenkins DJA, et al.Glycemic index, glycemic load and glycemic response: An International Scientific Consensus Summit from the International Carbohydrate Quality Consortium (ICQC).Nutr Metab Cardiovasc Dis. 2015;25(9):795-815. doi:10.1016/j.numecd.2015.05.005
Oregon State University: Linus Pauling Institute Micronutrient Information Center.Glycemic Index and Glycemic Load.
American Diabetes Association.Carb counting and diabetes.
American Diabetes Association.6. Glycemic targets: Standards of medical care in diabetes—2022.Diabetes Care. 2022;45(Supplement 1): S83–S96. doi:10.2337/dc22-S006
Harvard Health Publishing.A good guide to good carbs: The glycemic index.
American Diabetes Association. 5.Facilitating behavior change and well-being to improve health outcomes:standards of medical care in diabetes—2021.Dia Care. 2021;44(Supplement 1):S53-S72. doi:10.2337/dc21-S005Shukla A, Iliescu R, Thomas C, Aronne L.Food order has a significant impact on postprandial glucose and insulin levels. Diabetes Care. 2015; 38(7):e98-e99. doi:10.2337/dc15-0429
American Diabetes Association. 5.Facilitating behavior change and well-being to improve health outcomes:standards of medical care in diabetes—2021.Dia Care. 2021;44(Supplement 1):S53-S72. doi:10.2337/dc21-S005
Shukla A, Iliescu R, Thomas C, Aronne L.Food order has a significant impact on postprandial glucose and insulin levels. Diabetes Care. 2015; 38(7):e98-e99. doi:10.2337/dc15-0429
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