If you’re looking to improve your blood sugar control, prevent diabetes, or reverse prediabetes, glycemic index food charts can be helpful tools. Although it’s not perfect, the glycemic index does provide some simple and basic eating guidelines to follow.
In the following article, I’ll address:
- What is the Glycemic Index?
- How to use the glycemic index to improve your food choices
- Why the Glycemic Index is not a perfect guide to healthy eating
And, we’ll compare some glycemic index food lists by food group.
If you’re not in the mood to read, use the following table of contents to skip ahead to the glycemic index food charts.
Table of Contents
What is the Glycemic Index?
The glycemic index is a system of ranking carbohydrates based on how they impact blood sugar levels. Foods can rank between 0 to 100, depending on how rapidly they are digested and absorbed.
Carbohydrates closer to 0, have the least effect on your blood sugar, and are often referred to as “slow carbs”. Foods closer to 100 have the most immediate impact on your blood sugar, earning them the title “fast carbs”.
In general, foods with a high GI will result in higher peaks in blood sugar, compared to foods with a lower GI value.
How is Glycemic Index Measured?
Glycemic index is measured using either white bread, or pure glucose as a reference point. The reference food is assigned a value of 100. Then, 50 grams of carbohydrate from a test food is fed to a person who’s been fasting, and their blood sugar response is measured over a two hour period. That’s then compared against the response to the reference food (glucose or white bread).
For example, if a test food has a GI of 50, that means it has 50% of the glycemic response that occurs with straight glucose or white bread, depending on which one was used as the reference food.
It’s worth noting that when white bread is used as a reference point, some foods will have a GI greater than 100, because white bread technically has a lower GI than pure glucose.
How to Use Glycemic Index Food Charts
Glycemic index charts are not perfect, as I’ll touch on later. But, they can help us to better understand how a variety of carbohydrates influence our blood sugars. The key is to use these charts to choose foods that will not cause a drastic blood sugar spike. Or, if you do, try to pair them with low GI foods, or a protein to help dull the spike.
GI can be broken down into three categories.
High GI Foods (70 and above): These carbohydrates are rapidly digested and cause a quick spike in blood sugar. Common examples include sugary cereals, white bread, candy, deserts, and ice cream. But, high GI foods also include some vegetables like potatoes and even cooked carrots.
Medium GI Foods (56-69): These carbs are digested at a moderate pace, leading to a moderate increase in blood sugar. Examples include some fruits like pineapple, and mango, as well as certain grains and vegetables.
Low GI Foods (0-55): These carbohydrates are slowly digested and cause a gradual rise in blood sugar. Examples include most non-starchy vegetables, legumes, berries and most whole grains.
So, to keep your blood sugar from skyrocketing, you’ll want to limit or avoid foods that are high GI. Instead, try to increase your consumption of low GI foods. And, as for medium GI foods, those are best in moderation.
Remember – the lower the GI number, the lower the potential spike in your blood sugar levels. And the lower your blood sugar spikes, the less insulin is released as well.
A Glycemic Index List of Foods, by Food Group
To better understand, let’s take a look at some glycemic index charts by food group. You’ll notice that some food groups naturally have more high GI foods than others.
Grains tend to have a range of foods that fall across the spectrum from low to high GI. In general, the more processed a grain is, the less fiber it contains. And, as fiber is removed, GI tends to increase.
Check out the following glycemic index chart for grains. Do you notice any trends?
|High GI Grains
(> or equal to 70)
|Medium GI Grains
|Low GI Grains
|Special K Cereal
|Old fashioned rolled oats
rice (cooked 6 minutes)
Rice Cereal (Rice Krispies)
|Cream of wheat
|Rice noodles (boiled)
|Bran Flakes cereal
|Whole wheat pita
Why are Wheat Bread and White Bread both High GI?
You might have noticed that white bread and wheat bread are both considered high GI foods. Even though whole wheat bread is recommended as the healthier alternative to white bread, the GI can be fairly similar. There’s a number of reasons why.
In order to label a food as whole wheat it must contain at least 50% whole grain flour. And that’s a step in the right direction but it’s no miracle.
Remember what I said about fiber? The more fiber a food has, the lower the GI. So yes, a bread composed of 50% whole wheat flour has more fiber than a bread made from 100% white flour. But, it’s not enough fiber to make a dramatic difference in GI.
Instead, look for a bread that contains intact whole grains, or nuts and seeds. These higher quality breads will contain more protein and fiber, which also lower their glycemic index.
Dave’s Killer Bread is a good example of a high quality bread with good protein and fiber content. All three of the varieties below contain 5 grams of protein, and 4-5 grams of fiber.
A lot of people get carried away with eliminating fruit because they’re overly suspicious of sugar content.
But, whole fruits deliver sugar to your gut that are packaged with fiber. So, all that fiber in raw fruit slows the sugar absorption and makes them lower on the glycemic index than processed sugars, grains or starches. And, that fiber also helps feed your gut as a prebiotic.
Note – You’ll notice the only high GI fruit below is watermelon. But, don’t confuse watermelon as a bad guy. To find out why, don’t skip my section on why the glycemic index is imperfect, where I explain why watermelon is not as bad as the glycemic index makes it out to be.
|High GI Fruit
(> or equal to 70)
|Medium GI Fruit
|Low GI Fruit
|Canned Peaches in syrup
|Bananas (under ripe)
Most vegetables are low on the glycemic index, with the exception of starchy vegetables like potatoes, corn, parsnips and beets. It’s important to be aware of these starchy vegetables, but you don’t necessarily need to avoid them altogether. Check out the limitations of the glycemic index below, for a detailed explanation of why.
|High GI Vegetables
(> or equal to 70)
|Medium GI Vegetables
|Low GI Vegetables
|Parsnips, peeled and boiled
|Potato (instant, mashed)
|Unsweetened Carrot Juice
|Green peas (cooked)
Dairy and Dairy Alternatives
Most dairy foods are fairly low glycemic index, because naturally, most dairy and dairy alternatives have less carbohydrates and they also contain fat and protein which slows the absorption of sugars.
However, sweetened milk products like ice cream have a higher glycemic index. And, although vanilla ice cream technically has a medium GI, it doesn’t mean it’s a better option to whole fruits like watermelon which has a high glycemic index. Read on below to find out why.
|Medium GI Dairy
|Low GI Dairy
|Oat Milk (unsweetened)
|Vanilla Ice Cream
|Soy milk (unsweetened)
|Almond Milk (unsweetened)
Beans and Legumes
Some of the lowest GI foods tend to have a balance of macronutrients. Even though beans and legumes contain carbohydrates, they also are a good source of fiber and protein. That’s why you’ll see the glycemic index food list below only has a low glycemic index chart.
On average, beans and legumes only have a glycemic index of 34.
|Low GI Legumes
|Baked beans (canned)
Nuts are another good example of a well balanced food. Aside from having a balance of carbohydrates, fat, protein, fiber, GI cannot even be measured for many varieties of nuts because they have so few carbohydrates. That’s why nuts, on average, have the lowest glycemic index value by food group of 22.
|Medium GI Nuts
|Low GI Nuts
What are the Limitations of the Glycemic Index?
The glycemic index is often criticized for being incomplete. And that’s true. If you try to choose and eliminate foods solely based on their GI value, you’re likely to be misled.
The Glycemic Index Has a Portion Problem
The glycemic index does not take into account portion size. It only looks at the blood sugar response to 50 grams of carbohydrate from different foods.
But this is problematic, because for some foods, it’s highly unlikely that you’ll eat enough to actually consume that 50 grams. Let’s use watermelon as an example. It’s the only high GI fruit we previously identified.
The Watermelon vs Ice cream Example
Watermelon has a glycemic index of 72. But, watermelon is also 91% water. So, to get 50 grams of carbohydrate you’d have to eat about 5 cups of diced watermelon. That’s over 1.5 lbs of watermelon!
So, yes, watermelon is high on the glycemic index, but your stomach is going to burst before you eat enough to get that glycemic response.
Meanwhile, ice cream has a medium glycemic index of 60. Doesn’t that seem odd? If you were going on GI numbers alone, you’d ditch watermelon and replace it with ice cream.
BUT, instead of eating 5 cups of watermelon, you’d only need to eat 1 cup of ice cream to get 50 grams of carbohydrate.
The Case for Carrots vs Pasta
Similarly, carrots are often demonized for having a high GI. But, you’d have to eat 7 cups of carrots in order to get that 50 gram glycemic response. Meanwhile, it only takes about 1 cup of pasta to get 50 grams of carbohydrate.
Glycemic Load – A Better Way to Use Glycemic Index Charts
If we look solely at glycemic index, we can get tricked. That’s one of the reasons researchers came up with the concept of glycemic load, which is a more practical way to use the glycemic index of foods.
The glycemic load takes the glycemic index of a food, but then also takes the portion size into account. It does this by multiplying the GI by the grams of carbohydrate in a food serving, then divides it by 100.
- High glycemic load is ≥20
- Medium glycemic load is 11-19
- Low glycemic load is ≤10
For watermelon, a more reasonable portion size is 1 cup, which only has 11 grams of carbohydrates. So, the glycemic load of watermelon is = (72 GI x 11 grams) / 100, which equals 8, making it a low glycemic food.
For a more detailed breakdown of glycemic index and glycemic load, I recommend this article from Oregon State University.
How a Food is Cooked or Prepared Effects it’s GI
Another thing to know about the glycemic index is that it can change, depending on if, and how it’s cooked.
For example, potatoes are widely considered to be a high glycemic index food. But, according to the International Table of Glycemic Index, potatoes can range from 35-103 on glycemic index charts depending on how you cook them.
- Instant mashed potatoes have a GI of 84 for instant mashed potatoes,
- Regular mashed potatoes have a GI of 79
- Boiled potatoes have a GI of 73
- And cooked potatoes that were refrigerated overnight have a GI of 49
This can also be seen in the case of carrots, which people often label as a high glycemic vegetable. However, raw carrots have a gycemic index of 35, which is low. But when you cook them, the bonds begin to break down, causing the carbohydrate to more easily be absorbed, resulting in a glycemic index of 85.
So, how a food is cooked also effects GI. Even Al Dente pasta has a lower GI than overcooked pasta.
Glycemic Index is Not Always Consistent
This is one of the most frustrating things about glycemic index. If you look at several different sources across the internet, you’ll likely find different GI values.
- GI differs based on wether white bread or glucose is used as the control
- The GI of a food changes based on how it cooks
- GI can even differ randomly from person to person
- And GI can even differ in the same food or seemingly similar foods
Testing has even found variations in glycemic index for the same food in different countries.
For example, the GI of potatoes was found to vary as follows by region:
- 77 in Australia
- 73 in Europe
- 67 in North America
Even rice products were found to have GI variation by region:
- The highest GI value for rice 74 was seen in Asia
- Australia was 65
- Europe was 61
- North America had the lowest, 60
The GI of Ripe Fruit vs Unripened Fruit
As already discussed, the same food can have a different GI in different situations. That also applies to fruit. As it ripens, the glycemic index tends to increase. One reason this makes sense is that you’ll also notice fruit tends to sweeten as it becomes more ripe as well.
One fruit in particular this effects are bananas. When they are green, bananas have a GI closer to 42. But as they ripen and become more sweet their GI increases closer to 50, or more.
Mixing Foods Matters
The final criticism of glycemic index is that it does not take into account what else you eat with your meal. And, although we often snack on carbohydrates in isolation (think chips, pretzels, candy, fruit), we often eat foods grouped together. And, glycemic index only looks at foods in isolation.
But, we can reduce the glycemic impact of a food when we pair a high GI food with a low GI food or protein and fat. That’s one of the reasons it’s important to eat a balanced meal similar to the layout provided by the healthy eating plate below.
A Final Summary of Glycemic Index
Understanding the glycemic index can help you better understand how foods influence your blood sugar. However, it’s not a perfect tool. Instead, the glycemic load can give you a more realistic representation of how a food will effect your blood sugar.
Eating healthy is not as simple as “eat this, not that”. So, rather than avoiding foods with a high glycemic index, question why they’re high. And, don’t forget that portion control is always a variable when it comes to balancing your blood sugars. That’s why glycemic load can be so much more helpful for understanding glycemic index.