Glycemic index vs glycemic load
The glycemic index (GI) ranks carbohydrate foods from 0 to 100 by how quickly they raise blood sugar compared with pure glucose (GI 100). But GI ignores how much you eat. Watermelon has a high GI (about 76), yet a cup contains so little carbohydrate that its effect on blood sugar is small. The glycemic load (GL) fixes this by combining both — which makes it more useful for real meals. This free glycemic load calculator includes common South Asian and Middle Eastern foods such as basmati rice, roti, Arabic bread, dates and lentils.
How glycemic load is calculated
GL = GI × available carbohydrate (g) ÷ 100
Example: 1 cup of cooked white basmati rice (GI 58, about 40 g carbs) has a GL of 58 × 40 ÷ 100 = 23 (high). Three-quarters of a cup of cooked lentils (GI 32, 18 g carbs) has a GL of only 6 (low). For a meal, the GLs of each food are added together.
GI and GL chart: low, medium and high
| Measure | Low | Medium | High |
|---|---|---|---|
| Glycemic index (per food) | 55 or less | 56 – 69 | 70 or more |
| Glycemic load (per serving) | 10 or less | 11 – 19 | 20 or more |
| Glycemic load (whole day) | Under 80 | 80 – 120 | Over 120 |
Examples (approximate)
| Food & serving | GI | GL |
|---|---|---|
| Lentils, cooked, ¾ cup | 32 | 6 (low) |
| Apple, 1 medium | 36 | 5 (low) |
| Rolled oats porridge, 1 cup | 55 | 12 (medium) |
| Whole-wheat roti, 1 medium | 52 | 11 (medium) |
| Dates, 3 large | 42 | 17 (medium) |
| White basmati rice, 1 cup | 58 | 23 (high) |
| Cola, 1 can | 63 | 22 (high) |
| Boiled potato, 1 medium | 78 | 21 (high) |
Benefits of a lower-GL diet
- Smaller blood sugar spikes — helpful for diabetes, prediabetes, PCOS and gestational diabetes.
- Longer-lasting fullness and fewer cravings, which supports weight loss.
- Lower risk of type 2 diabetes and heart disease in large studies of low-GI/GL diets.
- Steadier energy through the day and during Ramadan fasts (choose low-GL suhoor foods).
Health warnings
- GI values vary with variety, ripeness, cooking time and what you eat alongside; treat numbers as estimates.
- Low GI does not always mean healthy — chocolate and some fried foods have a low GI because of their fat.
- People on insulin should still count total carbohydrates as advised by their diabetes team.
- Your own blood sugar response can differ — a glucose meter or sensor shows how you react.
Easy ways to lower the GL of your meals
Eat smaller portions of rice and bread with more vegetables and protein; choose basmati, parboiled or brown rice and whole-wheat roti; cook pasta al dente; cool and reheat rice and potatoes (more resistant starch); add vinegar, yoghurt or lemon; and eat fruit whole rather than as juice. Set your daily carb target, check your A1C, and see our diabetes-friendly breakfast ideas.
Frequently asked questions
What is a good glycemic load?
A glycemic load of 10 or less per serving is low, 11–19 is medium and 20 or more is high. For a whole day, under 80 is considered low.
What is the difference between GI and GL?
GI shows how fast a food’s carbohydrate raises blood sugar. GL also accounts for how much carbohydrate is in the portion you eat, so it reflects the real effect of a serving.
Is basmati rice low GI?
Basmati is usually medium GI (about 50–58), lower than many other white rice varieties. But a full cup still has a high glycemic load, so portion size matters.
Are dates high in glycemic load?
Dates have a low-to-medium GI (around 40–55), but they are rich in sugar, so 3 large dates have a medium GL. One or two dates with nuts or yoghurt have a gentler effect.
Is a low-GL diet good for weight loss?
It can help by keeping you fuller and reducing cravings, but total calories still matter. Combine low-GL choices with sensible portions.
Sources
- Atkinson FS, Foster-Powell K, Brand-Miller JC. International tables of glycemic index and glycemic load values: 2008. Diabetes Care 2008;31:2281–2283.
- Atkinson FS, et al. International tables of glycemic index and glycemic load values 2021: a systematic review. Am J Clin Nutr 2021;114:1625–1632.
- Livesey G, et al. Dietary glycemic index and load and the risk of type 2 diabetes. Nutrients 2019.