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A Hidden Gem: the Glycemic Index

STUDENT CONTRIBUTOR: Kalliopi (Kelly) Kyrani | School of Nutrition, Ryerson University

January 13, 2021

The Glycemic Index (GI) is a method of ranking carbohydrate-containing food or drink based on their impact on blood sugar after it is eaten or drunk. It is a scale out of 100 that compares food based on equal carbohydrate content, not equal amount of food. What determines the GI of a food is how quickly it's carbohydrates can be digested or absorbed. The faster they are digested and absorbed by the small intestine, the faster and higher the rise in blood sugar, and the higher the GI. Simply, foods with a high GI increase blood sugar higher and faster than low GI foods.

You may wonder how such a tool even came into existence, especially since its one that isn't all that well known outside of diabetes circles. Back in 1981, Dr. David Jenkins, a Professor of Nutrition at the University of Toronto, established the index.

It was initially used for finding out which foods were most favourable for people with diabetes. Dr. Jenkins wanted to examine the effect of different foods on blood sugar, rather than using lists of carbohydrates measured in grams. He quickly discovered that the variations were quite notable, even when comparing seemingly similar foods with the same amount of carbohydrates.

"Red Light, Green Light"

What should we understand about the different GI categories to achieve improved nutrition and blood sugar management? Are foods with low GI better than those with high GI? YES! Foods with low GI are - most of the time - a better choice!

Diabetes Canada recommends choosing foods with low GI most often, medium GI foods less often and those high on the GI the least often. Choosing foods in support of a low glycemic load (foods low on the GI scale) will help to improve overall health.

Speak to your Registered Dietitian to find ways to substitute high GI foods with foods in the low or medium GI category to improve the quality of your diet!

Why choose a low-glycemic index diet? What, are some benefits?

It is proven that carbohydrates with low glycemic index are ideal. A diet containing low GI foods can effectively decrease the risk of a variety of diseases such as type 2 diabetes and its complications, heart disease and stroke. Reduced cholesterol levels and blood sugar regulation are also benefits of a low glycemic index diet. Choosing low GI foods most often helps keep you feeling satisfied longer and lose or maintain weight!

Now, take a step back and think about which foods would you like to include in your diet But...wait! What are some good examples of low, medium, and high GI foods?

You can find more GI food examples here.

5 Meal Planning Ideas with the Glycemic Index:

  1. Choose foods that have a low to medium GI. Include fruits and milk with your meal.

  2. When eating a high GI food, combine it with a low GI food (e.g., protein) to balance the effect on your glucose levels. The GI of a food changes when you combine it with other foods. Some high GI foods are nutritionally rich; balance is key!

  3. Keep an eye to the portion size and number of carbohydrates! Portion size and calories still matter! Moderate portion size, choosing a variety of foods and selecting more whole foods than processed foods are keys to good health!

  4. Be careful! Cooking, processing, and ripeness of fruit can affect the GI! Juice has a higher GI than whole fruit. Al dente pasta has a lower GI than soft-cooked pasta.

  5. Try lower GI grains such as barley, bulgur, and pulses (beans, lentils, and chickpeas). Try swapping half of your higher GI grain/starch food serving with pulses. Instead of having one cup of cooked short grain rice, have ½ cup of cooked rice mixed with ½ cup of black beans.

And… don’t forget to check your blood sugar before, and two hours after a meal! It is the best way to know how your body handles certain foods and drinks!!!

What about Diabetes and Glycemic Index? Is it a helpful tool? For many people with diabetes, carbohydrate counting helps to manage the amount of carbohydrates to keep blood sugars closer to or within target range. Healthy food options along with carbohydrate counting, using the GI tool, and managing a healthy weight lowers the risk for diabetes-related complications. It's highly recommended that people with diabetes speak with their health provider(s) or registered dietitian about using the glycemic index as part of their nutrition and blood sugar management action plan!

If you are interested in learning more, we welcome you to book a session with our Registered Dietitian who can help you make positive changes in your eating habits for improved blood sugar control and optimal long-term health and wellness!

Test yourself!

1. What is the Glycemic Index?

2. Who invented the Glycemic Index?

3. What are some low GI foods?

4. How can a low Glycemic diet help control diabetes?

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