The Glycemic Index Simplified for Better Blood Sugar Control

Written by and medically reviewed by Michaela Harron, Registered Dietitian. Published November 27, 2025.

Whether you have been diagnosed with pre-diabetes, diabetes or are just trying to support your body’s blood sugar response, the glycemic index is something that is important to understand.

In today’s post, we are going to cover what glycemic index is, why it is important, and give some examples of how to build a blood-sugar friendly diet using glycemic index!

What is glycemic index?

The Glycemic Index (GI) is a scale out of 100 that ranks a carbohydrate-containing food/drink by how much it raises your blood sugar levels after it is consumed. If a food is higher in the GI, it will mean that it is more quickly digested, and therefore breaks down into sugar more quickly, raising blood sugars.

For example, 1 cup of orange juice juice is higher in the GI compared to 1 cup of orange slices, and therefore will lead to a more significant blood sugar increase after consumption. The orange juice comes from an orange, but in the process of making juice, we remove the fibre from the orange, which helps slow down the breakdown of sugar in the blood.

Classifications for the glycemic Index

The glycemic index (GI) measures how quickly foods raise your blood sugar. Pure glucose (sugar) is the benchmark, set at 100, and other foods are ranked in comparison.

Low GI: 55 or less
Medium/moderate GI: 56 – 69
High GI: 70+

For example, white bread would have a GI of 71 (high), whereas an apple would have a GI of 40 (low), and brown rice at 66 (moderate/medium GI).

In general, lower glycemic index foods tend to be higher in fibre, because the fibre helps pump the brakes on the release of sugar, making it raise blood sugar to a lesser degree and with a slower release over time. This slow release of glucose into the bloodstream is much more beneficial for the body and can support sustained energy levels and help with weight loss or maintenance, diabetes and other health concerns.

Other factors that contribute to the glycemic response include the amount of food consumed, how much the food is processed and even how the food has been prepared. For example, pasta that is cooked al dente has a slower glycemic response than pasta that is overcooked.

Glycemic Index Plate Method

The glycemic index only refers to the carbohydrate in foods, but we (hopefully) don’t only eat carbohydrates at meals, so we have to also consider the other components of our meal to determine the effect on blood sugar.

Protein and fat have very minimal effects on blood sugar, and when eaten with a source of carbohydrate, can also further blunt the blood sugar response. This is because they can slow the release of sugar in the blood due to their ability to delay stomach emptying.

Combining low GI carbohydrates with protein and fat will give you an even lower blood sugar response! This is the structure you are ideally aiming for to create a blood sugar-friendly meal:

¼ plate mostly low GI carbohydrates
¼ plate protein
½ plate non-starchy vegetables
1 tbsp/1 thumb of healthy fats.

Strategies to lower the glycemic index of a meal

Cook Al Dente
Cook pasta ‘al dente’ (firm). Since al dente pasta requires more work from the body during digestion, the digestion rate is slower and, therefore, the GI is lower.
Pair with Dairy or Fruit
Make fruits and milk part of your meal. These foods often have a low GI.
Choose Lower GI Grains
Try lower GI grains, such as quinoa, barley and bulgur.
Mix in Legumes
Swap half of your higher GI starch food serving with beans, lentils or chickpeas. For example, instead of having 1 cup of cooked rice, have 1⁄2 cup of cooked rice mixed with 1⁄2 cup of black beans.
Cool, Then Reheat
Cool potatoes or rice after cooking and enjoy them cold (potato salad) or re-heat later. The cooking then cooling of the starches in rice and potatoes increases resistant starch which has a lower effect on blood sugar
Focus on Fibre
Read labels for fibre content. You might not be able to tell the exact glycemic index of a food from the label, but you can get an idea by looking at the amount of fibre on the Nutrition Facts Table. The higher the fibre content, the more this will help lower the glycemic index of that carbohydrate

Key Takeaways: Glycemic Index Simplified for Better Blood Sugar Control

In summary, glycemic index is something that is very important to understand, whether you are facing a diagnosis of pre-diabetes, diabetes, or just trying to support blood sugars and energy levels for general health.

Since glycemic index ranks carbohydrate-containing foods/drinks by how much they raise your blood sugar levels, we can use this information to learn how to properly balance our food intake to create more stable blood sugars. More stability in blood sugars can also lead to things like more stable energy levels- bonus!

To learn more about glycemic index and how to include it in your day-to-day eating pattern, schedule a session with one of our dietitians! We help put knowledge into practice with easy-to-implement strategies that won’t leave you feeling overwhelmed or confused!