How to Calculate the Glycemic Index of Food

How to Calculate the Glycemic Index of Food

The glycemic index, or GI, is an approach of ranking foods, from 0 to 100, based upon how they influence your blood glucose levels. Greater GIs suggest foods that will cause your blood sugar level to rise higher and faster than foods with lower GIs. Type 1 and Type 2 diabetics can benefit from taking in low-GI diets because they help manage blood glucose and insulin levels, and they can likewise reduce insulin resistance. The GI worths of lots of foods have been clinically figured out and tape-recorded, so determining the GI of a meal is easy.

Calculation of the Glycemic Index

Action 1

Determine the number of carbs remain in each portion of your meal. For instance, consider a breakfast of immediate oatmeal and an 8-ounce glass of orange juice. One packet of instant oatmeal consists of 22 grams of carbohydrate, and 8 ounces of orange juice has 26 grams of carbohydrates.

Action 2

Determine the proportion of carbohydrates each meal component adds to the meal. Divide the overall grams of carbohydrates by the number of grams contributed by the specific component to find the proportion of carbs for the part. For instance, there are 48 total grams of carbohydrates in the meal of orange juice and oatmeal. Divide 22 grams by 48 grams to figure out that the proportion of carbs from oatmeal is 0.46, and the percentage of carbohydrates from the orange juice is 0.54.

See also: How Many Carbohydrates Should I Have?

Action 3

Increase the proportions for the meal parts by the predetermined GI of that component. GIs of specific foods can be discovered in an online GI database or in the table published by “The American Journal of Clinical Nutrition.” For example, the GI of oatmeal is 83. Multiply 0.46 by 83 to obtain 38.18. For the orange juice, increase 0.54 by the GI of 46 to obtain 24.84.

Action 4

Add the outcomes of Step 3 together. In this example, include 38.18 and 24.84 to get the sum of 63.02, which is the overall glycemic index of the meal.


You need to not rely solely on the glycemic index to identify how your meal will affect your blood glucose levels. Test your blood sugar level inning accordance with guidelines from your doctor or registered dietitian.


It helps to tape-record your estimations step-by-step to obtain as precise a result as possible.

Things You’ll Need
  • Glycemic index table or database
  • Calculator
  • Pencil and paper

You can also watch this video about calculating GI:

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