What Is the Glycemic Index?
The glycemic index (GI) is a scale from 0 to 100 measuring how quickly carbohydrates in a food raise blood sugar compared to pure glucose (GI = 100). The higher the GI, the faster and larger the blood sugar spike.
- Low GI (≤ 55): gradual blood sugar rise, stable energy
- Medium GI (56–69): moderate rise
- High GI (≥ 70): rapid glycemic peak, then energy crash
Not to be confused with glycemic load (GL), which considers both GI and the amount of carbohydrates consumed: GL = GI × carbs (g) / 100.
Complete Table: Glycemic Index of Common Foods
| Food | GI | Category | GL (standard portion) |
|---|---|---|---|
| Pure glucose | 100 | 🔴 High | – |
| White baguette | 95 | 🔴 High | 15 (1 slice) |
| Cooked white rice | 72 | 🔴 High | 29 (200g) |
| Steamed potato | 70 | 🔴 High | 14 (150g) |
| Whole grain bread | 65 | 🟡 Medium | 9 (1 slice) |
| Basmati rice | 58 | 🟡 Medium | 23 (200g) |
| Rolled oats | 55 | 🟢 Low | 13 (50g) |
| Whole sourdough bread | 54 | 🟢 Low | 8 (1 slice) |
| Cooked quinoa | 53 | 🟢 Low | 13 (200g) |
| Sweet potato | 50 | 🟢 Low | 11 (150g) |
| Lentils | 30 | 🟢 Low | 5 (150g) |
| Chickpeas | 28 | 🟢 Low | 5 (150g) |
| Apple | 36 | 🟢 Low | 4 (1 medium) |
| Whole milk | 27 | 🟢 Low | 3 (250ml) |
| Walnuts | 15 | 🟢 Low | 0 (30g) |
Why High GI Promotes Weight Gain
When you eat a high-GI food, blood sugar rises rapidly. The pancreas secretes large amounts of insulin to bring sugar into cells. Insulin is the fat-storage hormone: it inhibits lipolysis (fat breakdown) and promotes lipogenesis (fat creation).
Moreover, the reactive hypoglycemia following the glycemic peak causes intense hunger 2–3h after eating, encouraging snacking.
A low-GI meal (lentils + vegetables + chicken) maintains satiety for 4–5h vs 2–3h for a high-GI meal (white pasta + sauce).
Factors That Modify a Food's GI
- Cooking: al dente pasta (GI 45) vs overcooked (GI 65)
- Physical form: whole apple (GI 36) vs apple juice (GI 44)
- Fiber, fat, protein content: slows absorption
- Cooling: cooled rice or potato has ~15% lower GI
- Fruit ripeness: ripe banana (GI 65) vs green banana (GI 30)
How to Integrate Low GI Into Daily Life
- Replace white rice with quinoa, basmati, or brown rice
- Choose whole sourdough bread over white baguette
- Add legumes to your dishes 3×/week
- End meals with fresh fruit rather than sugary desserts
- Eat carbohydrates last in the meal (after vegetables + protein)
Mastering the glycemic index doesn't mean eliminating carbs, but choosing the right carbs at the right time. Nutrya automatically calculates the GI and glycemic load of your meals to help you make the best choices.