📊 Glycemic and insulin indexes: impact on hormonal response
How carbohydrates affect blood sugar and insulin
Glycemic index (GI) shows how quickly a food raises blood sugar. Insulin index (II) measures how much insulin the body releases in response to a food. These indicators matter for glucose control, insulin sensitivity and hormonal response after meals.
What is the glycemic index
GI is a measure of how fast a food's carbohydrates raise blood glucose relative to glucose or white bread (set at 100). The higher the GI, the faster and stronger the sugar rise.
| Range | Interpretation |
|---|---|
| ≤ 55 | Low GI |
| 56–69 | Medium GI |
| ≥ 70 | High GI |
A related concept is glycemic load (GL), which accounts for both GI and the amount of carbohydrates in a serving. GL = (GI × grams of carbs) / 100.
What is the insulin index
II measures the body's insulin response to a serving of food. Interestingly, some low-GI foods (like protein and meat) can still trigger a significant insulin release. II was introduced in 1997 by Australian researchers (Holt et al.).
- II reflects insulin release, not only glucose.
- Proteins and some fats also affect insulin.
- GI and II do not always match.
- II matters in insulin resistance.
GI vs II
| Parameter | GI | II |
|---|---|---|
| What it measures | Blood sugar | Insulin release |
| Introduced | 1981 (Jenkins) | 1997 (Holt) |
| Effect of proteins | Weak | Significant |
| Practical use | Sugar control | Insulin sensitivity |
Food tables
GI examples
| Food | GI | Comment |
|---|---|---|
| Glucose | 100 | Reference |
| White bread | ~75 | High |
| Oatmeal | ~55 | Medium |
| Lentils | ~30 | Low |
| Broccoli | ~15 | Low |
How to lower the GI of a meal
- Add fiber — it slows absorption.
- Pair carbohydrates with protein and fats.
- Choose whole grains over refined ones.
- Watch cooking method (overcooked foods are higher GI).
Practice and nutraceuticals
In impaired insulin sensitivity, besides diet some supplements may help:
| Supplement | Proposed action |
|---|---|
| Berberine | Support of insulin sensitivity |
| Chromium picolinate | Carbohydrate metabolism support |
| Alpha-lipoic acid | Antioxidant support |
| Inositol | Insulin signaling |
What is the glycemic index?
The speed at which blood sugar rises after a food.
How does II differ from GI?
II measures insulin release, GI measures glucose.
What is glycemic load?
A measure accounting for both GI and carbs in a serving.
Which foods are low GI?
Lentils, broccoli, most vegetables, whole grains.
Does protein affect insulin?
Yes, protein can cause an insulin response even with low GI.
How to lower the GI of food?
Add fiber, protein and fats; choose whole grains.
Do supplements help with high GI?
Berberine, chromium and inositol may support insulin sensitivity.
GI and diabetes?
A low-GI diet helps control sugar in diabetes.
Is GI the same for raw and cooked food?
No, cooking usually raises the GI.
Is II important for weight loss?
Considering II helps control insulin, which matters in obesity.