🥖 Glycemic Index Calculator
Convert glucose response data into glycemic index values and estimate glycemic load per serving.
Incremental area under the blood glucose curve (0-120 minutes).
Use the mean IAUC of the reference food (glucose or white bread).
Usually 50 grams of available carbohydrate.
Optional. Needed to compute glycemic load (GL) for a typical portion.
GI = (IAUC test ÷ IAUC reference) × 100 • GL = (GI ÷ 100) × carbs per serving
How to Use This Calculator
Collect IAUC data
Measure incremental area-under-curve values for your test food and the reference food under identical laboratory conditions.
Enter carbohydrate information
Confirm the grams of available carbohydrate used in the standardized test and optionally add grams for a typical serving size to compute glycemic load.
Review GI and GL classification
The tool returns the glycemic index, categorical rating, and glycemic load so you can compare foods and plan meals.
Formula
The glycemic index is defined as the relative blood glucose response to a carbohydrate-containing food:
- GI = (IAUCtest ÷ IAUCreference) × 100
- Glycemic Load (GL) = (GI ÷ 100) × grams of available carbohydrate per serving
- Low/medium/high categories follow ISO 26642 standards and International Tables of Glycemic Index values.
IAUC (incremental area under the curve) excludes the area below fasting baseline and is typically calculated over 2 hours using the trapezoidal method.
Full Description
Glycemic index compares how quickly carbohydrate foods raise blood glucose relative to a reference (pure glucose or white bread). Foods with lower GI values cause slower, more gradual increases in blood sugar, which is beneficial for people with diabetes or those aiming for sustained energy levels.
However, GI alone does not account for portion size. Glycemic load complements GI by incorporating the amount of carbohydrates consumed in a typical serving, providing a more practical picture of postprandial glucose impact.
This calculator is helpful for nutrition researchers, dietitians, and individuals fine-tuning dietary plans. Combine GI/GL data with overall dietary quality, fiber intake, and personal glucose monitoring for optimal results.
Frequently Asked Questions
What is the reference food for GI?
Most laboratories use pure glucose (GI 100). Some use white bread (GI 70). Ensure you match the reference when comparing published values.
Why is IAUC required?
The incremental area under the glucose curve captures the total rise in blood glucose over time, providing a standardized measure of glycemic response.
Can I estimate GI without lab testing?
Published GI tables may provide approximate values, but individualized testing requires controlled laboratory protocols. Home estimates based on personal glucose monitors will be less precise.
How do fiber and fat affect GI?
Fiber, fat, and protein slow gastric emptying and can lower the glycemic response. Whole foods with intact fiber generally have lower GI values than refined carbohydrates.
What is a good glycemic load target?
Aim for a daily glycemic load under 100 for balanced blood sugar management. Low-GL meals (10 or less) are ideal for keeping post-meal glucose stable.