Glycemic index and glycemic load: what they mean, how they differ and a food table
The glycemic index (GI) tells you how fast a given food raises your blood glucose. The glycemic load (GL) adds a second, crucial piece of information — how much carbohydrate is in a real portion. That's why it's the GL, not GI alone, that best predicts what will actually happen to your blood sugar after a meal.
Important: this article is for information only and does not replace advice from a doctor or dietitian. The GI/GL values of foods are approximate — they depend on the variety, ripeness, processing and what you eat alongside them.
Glycemic index (GI): how fast blood sugar rises
The GI is a 0–100 scale that compares the rise in glucose after a given food to a reference (pure glucose = 100). The higher it is, the faster and higher the peak. By convention:
| Low GI | Medium GI | High GI |
|---|---|---|
| ≤ 55 | 56–69 | ≥ 70 |
Why GI alone can be misleading
A classic example: watermelon has a high GI (~72), but a real portion has so little carbohydrate that its effect on blood sugar is small. The opposite happens with "moderate" GI foods that we eat a lot of. GI alone ignores portion size — and this is where glycemic load comes in.
Glycemic load (GL): how fast × how much
The GL combines quality (GI) with the amount of carbohydrate in a portion: GL = GI × carbs in portion (g) / 100. By convention:
| Low GL | Medium GL | High GL |
|---|---|---|
| ≤ 10 | 11–19 | ≥ 20 |
In practice you don't have to do the math — just remember the direction: a small portion of a high-GI food can be harmless, while a large portion of a "moderate" one can push your blood sugar up sharply.
Table: GI and approximate GL of a typical portion
| Food | GI | GL of portion |
|---|---|---|
| Lentils, chickpeas, beans | low (~30) | low |
| Oats (rolled oats), buckwheat | low–medium | low–medium |
| Rye sourdough bread | medium | medium |
| Apple, pear, berries | low | low |
| Banana (ripe) | medium | medium |
| Pasta al dente | medium (~50) | medium (depends on portion) |
| White rice, overcooked | high (~70+) | high |
| Mashed potatoes | high (~80+) | high |
| White bread, rolls | high (~70+) | high |
| Sweetened drinks, juices | high | high |
| Watermelon | high (~72) | low (few carbs per portion) |
How to lower a meal's glycemic load
You don't have to give up your favorite foods — just change the context:
Add protein, fat and fiber. Carbohydrates "solo" give the highest peak; alongside an egg, olive oil or vegetables — a flattened one.
Change the order. Vegetables and protein before carbohydrates genuinely lower post-meal glucose.
Al dente and cooling. Shorter cooking and cooling potatoes, rice or pasta (resistant starch) soften the peak — even after reheating, part of the effect remains.
Acid. Vinegar or lemon juice in a meal (e.g. in a salad dressing) lowers the glycemic response.
Who GI and GL matter most for
For people with diabetes and insulin resistance (including PCOS) — because it translates directly into glucose and insulin release. But when losing weight too, a lower GL means steadier energy and fewer hunger pangs. For a healthy person eating a varied diet, GI is one of many tools, not an oracle.
How Bilberry simplifies this
Instead of leafing through tables: photograph your plate or describe a meal — Bilberry will estimate the calories and carbohydrates, and your weekly meal plan is arranged to keep the glycemic load in check (home cooking, on budget, with a shopping list).
Frequently asked questions
Do fruits have a high glycemic index? Most fruits (berries, apple, pear) have a low or medium GI and a low load per portion — provided you eat them whole, not as juice.
Is the glycemic index everything? No. Portion matters (hence GL), so does what else is on the plate and the order you eat in. The GI of a single food, divorced from the meal, can be misleading.
Do I have to cut out potatoes, rice and pasta? No — mind the portions, choose whole grain, cook al dente and eat them cooled too, always with protein and vegetables.
Does a healthy person have to watch GI? They don't need to count — but the same principle (fewer "fast" sugars, more fiber and protein) improves energy and satiety anyway.
A low glycemic load without the tables
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