Tools & References

Glycemic Load

Glycemic index tells you how fast. Glycemic load tells you how much. Put the two together and you finally have the honest picture of what a real portion does to your blood sugar.

Why GI alone can mislead

Speed is only half the story

Watermelon has a high glycemic index, which sounds alarming. But a normal serving contains very little actual carbohydrate, so its real effect on your blood sugar is small. The glycemic index exaggerated the danger.

Glycemic load (GL) fixes this by combining the speed (GI) with the portion (how many grams of carbohydrate are actually on your plate). It answers the question that matters: what will this serving, as I actually eat it, do to me?

The simple formula

Speed times portion

Glycemic Load = (GI × grams of carbohydrate per serving) ÷ 100

You never have to calculate this yourself. Just know the bands below, and the rule of thumb that follows.

BandGL per servingWhat it means
Low10 or underGentle. Build most meals from these.
Medium11 to 19Reasonable in a balanced meal with protein and fat.
High20 and upA real spike. Keep occasional, and never alone.
The same food, two portions

Portion is power

WatermelonHigh GI (about 72), but a normal slice is low GL (about 4). The scary number, harmless in a real serving.
White riceHigh GI and a large portion means high GL (often 25+). A genuine flood, worth reducing or pairing.
CarrotsTheir GI gets a bad reputation, but the GL of a normal serving is tiny. Eat carrots freely.
A can of colaHigh GI and about 40g of sugar means a very high GL. This is the flood you feel an hour later.
"You do not need to memorise numbers. Favour whole foods, keep starchy portions modest, and pair them with protein and fat. That is glycemic load, handled."

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SourcesAtkinson FS, Foster-Powell K, Brand-Miller JC. International tables of glycemic index and glycemic load values. Diabetes Care, 2008. • Salmeron J, et al. Dietary fiber, glycemic load, and risk of type 2 diabetes. JAMA, 1997. • Liu S, et al. Glycemic load and chronic disease risk. American Journal of Clinical Nutrition, 2002.
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