The glycemic index (GI) is a scoring system. The score for a given food shows how quickly your body can break down the carbs in that food — and how this can affect your blood sugar.
Low-GI foods have a low score on this index.
The body tends to break down low-GI foods slowly. This means that it takes a while for your blood sugar levels to rise after you eat.
On the other hand, the body breaks down high-GI foods quickly. This can lead to blood sugar spikes and crashes.
The index is a tool to predict these blood sugar effects in general. But the scores won’t be accurate for everyone because each person responds to food in a unique way.
With the ZOE at-home test, we can measure your unique blood sugar and blood fat responses to different foods. With this information, we can give you personalized nutrition advice about which foods may be best for your body.
To get started, take our free quiz.
Why do blood sugar responses matter?
After you eat, it's completely normal for your blood sugar levels to rise. After all, this is how food fuels your body. As your cells take up the sugar from your blood, your levels fall again.
If your blood sugar levels rise too rapidly too often and tend to stay high for a long time, it can cause inflammation. And inflammation can play a role in many chronic conditions, such as type 2 diabetes, certain cancers, and heart disease.
Low-GI foods are more likely than other foods to lead to more moderate rises in blood sugar and more gradual reductions.
Research suggests that our blood sugar responses affect our hunger and energy levels after we eat.
Some people have big blood sugar spikes. This can then lead to blood sugar crashes, and it can leave you feeling hungry and tired.
Avoiding frequent spikes and crashes can benefit your overall health and your risk of chronic conditions.
Low-GI foods
How your body’s blood sugar levels rise and fall after you eat is unique to you. The GI can only serve as a general guide.
GI scores range from 1–100, and they’re grouped into low, medium, and high categories:
Low = 55 or less
Medium = 56–69
High = 70 or over
Low-GI foods can be beneficial because they cause blood sugar levels to rise and fall more gradually, making spikes and crashes less likely.
There are plenty of low-GI foods you can easily swap into your diet.
| Fruits and veggies | GI scores (glucose = 100) |
|---|---|
| Sweet corn | 52 ± 5 |
| Orange | 43 ± 3 |
| Dates | 42 ± 4 |
| Carrots | 39 ± 4 |
| Pears | 38 |
| Apples | 36 ± 2 |
| Peas | 22 |
| Broccoli | 15 |
| Tomatoes | 15 |
| Spinach | 1 |
| Legumes | GI scores (glucose = 100) |
|---|---|
| Lentils | 32 ± 5 |
| Chickpeas | 28 ± 9 |
| Kidney beans | 24 ± 4 |
| Soy beans | 16 ± 1 |
| Grains, pasta, and noodles | GI scores (glucose = 100) |
|---|---|
| Udon noodles | 55 ± 7 |
| Rice noodles | 53 ± 7 |
| Spaghetti, whole meal | 48 ± 5 |
| Barley | 28 ± 2 |
| Breads | GI scores (glucose = 100) |
|---|---|
| Speciality grain bread | 53 ± 2 |
| Corn tortillas | 46 ± 4 |
| Dairy and dairy alternatives | GI scores (glucose = 100) |
|---|---|
| Yogurt, fruit | 41 ± 2 |
| Milk, full fat | 39 ± 3 |
| Milk, skim | 37 ± 4 |
| Soy milk | 34 ± 4 |
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Possible benefits of a low-GI diet
There are several potential benefits of a low-GI diet, including:
a lower risk of type 2 diabetes
improved cholesterol levels
a lower risk of certain cancers
a lower risk of heart disease
How important are GI scores?
GI scores can be a good predictor of changes in blood sugar levels generally. But different people have different responses to food.
In fact, ZOE research has shown that these responses can vary greatly, even among identical twins.
Also, the index only scores individual foods — it doesn’t take into account how your body responds to different combinations of foods.
Many of the factors that affect your blood sugar responses are unchangeable, like your genes and age. But you can minimize the chances of big blood sugar spikes and crashes by changing the foods you eat.
With the ZOE at-home test, you can learn how different foods impact your blood sugar and blood fat, as well as your gut health.
Based on your unique results, we can give you personalized nutrition recommendations.
To get started, take our free quiz.
Summary
GI scores show how quickly the body breaks down the carbs in different foods — and how this affects blood sugar levels.
Blood sugar spikes and crashes can have a significant effect on your hunger and energy levels, and on your health in the long term.
Low-GI foods tend to include vegetables, fruits, legumes, and whole grains.
It’s important to note, though, that GI scores don’t take into account how your body responds to combinations of foods.
At the end of the day, the index can help guide you toward healthy, balanced eating, but it can’t tell you how your body will respond to different foods. Foods with high GI scores aren’t necessarily bad for you.
With ZOE’s personalized nutrition program, you can discover how to eat for your body and your long-term health goals.
Sources
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Glycemic index, glycemic load and glycemic response: an international scientific consensus summit from the International Carbohydrate Quality Consortium (ICQC). (2015). https://www.sciencedirect.com/science/article/pii/S0939475315001271
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International tables of glycemic index and glycemic load values 2021: A systematic review. The American Journal of Clinical Nutrition. (2021). https://academic.oup.com/ajcn/article/114/5/1625/6320814
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Low-glycemic index diets as an intervention for diabetes: A systematic review and meta-analysis. (2019). https://academic.oup.com/ajcn/article/110/4/891/5543221
Low glycemic index diet, exercise and vitamin D to reduce breast cancer recurrence (DEDiCa): Design of a clinical trial. (2017). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5259892
Postprandial glycaemic dips predict appetite and energy intake in healthy individuals. (2021). https://www.nature.com/articles/s42255-021-00383-x
What is the glycemic index? (2022). https://www.nhs.uk/common-health-questions/food-and-diet/what-is-the-glycaemic-index-gi
