Methodology & sources

Data last reviewed 2026-09-29

Every number on this site can be traced back to a published source. This page explains how we choose and calculate them.

Glycemic index

GI values come from the International Tables of Glycemic Index and Glycemic Load Values 2021 (Atkinson et al., American Journal of Clinical Nutrition), the most complete compilation available, with more than 4,000 foods tested worldwide. The tables separate studies that followed the ISO 26642 standard method from those that used less strict methods; we use both lists.

For each food:

When the authors of the tables published a mean for that food (for example, "white wheat flour bread, mean of 35 studies"), we use that value.
Otherwise we gather every measurement that matches the generic food, excluding products with added ingredients, and use the median, which is less sensitive to outliers than the average.
Every food page shows the number of studies, the range and each individual measurement with its country and year.

In total, the 173 foods with a GI on this site rely on 1160 individual measurements.

Foods without a glycemic index

Meat, fish, eggs, oils, hard cheeses and non-starchy vegetables contain too little carbohydrate for GI to be measured (the test needs portions with 25 or 50 g of carbohydrate). We show them as "no GI", with a glycemic load of about 0.

Glycemic load

Glycemic load = GI × available carbohydrate in the serving ÷ 100. Available carbohydrate is total carbohydrate minus fiber, from USDA data. Servings follow common sizes (for example 120 g of fruit, 30 g of bread, 150 g of cooked rice) and are shown on every page.

Cut-offs: low ≤ 10, medium 11–19, high ≥ 20 per serving. For GI: low ≤ 55, medium 56–69, high ≥ 70.

Nutrition data

Calories, carbohydrate, fiber, sugars, protein and fat come from USDA FoodData Central (SR Legacy and FNDDS databases). Each page links to the exact record used.

Limitations

A food’s GI varies with variety, ripeness, cooking and processing. Values are representative, not exact for your meal.
Individual responses can differ from averages.
Some foods have a single published measurement; we say so on their page.

This information is educational and does not replace advice from a health professional.

References

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. Am J Clin Nutr. 2021;114(5):1625–1632. doi:10.1093/ajcn/nqab233
ISO 26642:2010. Food products — Determination of the glycaemic index (GI) and recommendation for food classification.
U.S. Department of Agriculture, Agricultural Research Service. FoodData Central. fdc.nal.usda.gov