How To Calculate Glycemic Index From Food Labels

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By : dLife Editors

Following a low glycemic index diet is one of the ways people living with diabetes can have better control of their blood sugar levels. When foods low in GI are consumed, it gradually raises the blood sugar and doesn’t spike insulin level like high GI foods will do.

This is because this type of foods is digested and absorbed more slowly than high GI foods and are thus recommended for people with diabetes.

However, because food labels don’t come with the food’s glycemic index score, it could be a bit difficult to effectively maintain diabetes condition with low glycemic index meals.

But even though you can’t find glycemic index information on food packaging, it doesn’t mean you can’t have an idea of what GI score the food carries.

The ever-present nutrition information on the label is just a valuable tool enough for you to find the best low GI choices next time you are in the store shopping for low glycemic foods. Knowing what to check on the food label can make life much easier for you as you search the store.

#1: Carbohydrate Content

Checking your food label, you must also remember that the term carbohydrate as written on the label includes the sugars and starches in the food. The fiber content of the food is not included here because fiber is not broken down during digestion.

Therefore “Total carbohydrate” of the food includes sugars, starch, and the fiber in the food. This means foods made with sugar and flour tend to have higher glycemic index than the ones made with whole grains intact because their fiber content has been ripped off during processing and thus left with more sugar and starch content than fiber.

#2: Protein and Fat Content

Fat and protein have little effect on your blood sugar, therefore, foods high in ratio of fat and protein to carbohydrate tend to be lower in glycemic index scores. The same way, when you eat high glycemic index foods along with a source of fat or protein, you can reduce the overall glycemic index of such meal.

#3: Fiber Content

Compared to foods with no or little fiber content, foods rich in fiber tend to have a lower glycemic index score, especially if it is soluble fiber. Fiber is known to digest more slowly and thus slows down the digestion of food, therefore, resulting in a slower release of sugars into the bloodstream. This, therefore, results in a smaller and slower increase in the blood sugar and a lower GI.

#4: GI Labelling

Even though it may be difficult to tell the GI score of a food by mealy looking at the label, a quick way to tell if the food is low in GI is to look out for the low GI Symbol on the food packaging. The symbol is a sole guarantee that the GI value of the food is as stated on the label and can be trusted.

Easy 4 Steps to Determine the GI of Your Meal:

For foods without labels, you can as well calculate their GI by following these four simple steps:

Things you will need:

  • Calculator
  • Glycemic index table or database
  • Pencil and paper

Step 1:

Determine the carbohydrate content of each portion of the meal. For instance, let’s say a breakfast involving an 8-ounce glass of orange juice and instant oatmeal is what you plan to have. There are 22g of carbohydrate in a packet of instant oatmeal and 26 g in 8 ounces of orange juice.

Step 2:

Find the proportion of carbs each component adds to the meal by dividing the total grams of carbs by the gram contributed by each component. For instance, in our example above, there are 48g of carbs in the meal. Divide 22g by 48g to get the proportion of carbs oatmeal is adding to the meal and also divide 26g by 48g to find for 8 ounces of orange juice. It will give a result of 0.46 for oatmeal and 0.54 for orange juice.

Step 3:

Multiply the proportions for the components by the standard glycemic index of the component. You can find the standard or predetermined GI of such component on a GI table or database. For instance, the GI of oatmeal on such table is 83. Still using our meal above, multiply 0.46 by 83 to get 38.18 for oatmeal and 0.54 by 46 to get 24.84 for orange juice.

Step 4:

Add the result you obtained in step 3 together. In our example, you will be adding 38.18 and 24.84 to get the sum of 63.02. This means the total glycemic index for the breakfast comprising of an 8-ounce glass of orange juice and an instant oatmeal is 63.02.

Bottom line

You don’t have to wreck your health because there is no direct GI score written on your food label, knowing the right things to check on the label is enough for you to determine that without any hassle, even for your meals.  Read about whether you should follow a low GI diet here.


1. Diabetes Forecast magazine. (2014, June 27). Taking a Closer Look At Labels. American Diabetes Association. Retrieved from

2. Elham, M., Janet, A. V., Thomas, M. S., Wolever. (2006, Oct 1) The Effects of Fat and Protein on Glycemic Responses in Nondiabetic Humans Vary with Waist Circumference, Fasting Plasma Insulin, and Dietary Fiber Intake. The Journal of Nutrition, Volume 136, Issue 10, 1 October 2006, Pages 2506–2511. Retrieved from

3. Glycemic Index Foundation. The Low GI Symbol. Retrieved from