What is Glycemic Index?

The Glycemic Index (GI) is a relative ranking of carbohydrate in foods according to how they affect blood glucose levels.

The Scale

The Glycemic Index (GI) is a relative ranking of carbohydrate in foods according to how they affect blood glucose levels. Carbohydrates with a low GI value (55 or less) are more slowly digested, absorbed and metabolised and cause a lower and slower rise in blood glucose and, therefore usually, insulin levels.

There are three classifications for GI:

Individual food portion:

Low: 55 or less

Mid:  56 – 69

High: 70+

Whether you are looking to improve your general health, have sustained energy or help manage a specific health condition, low GI can help you do just that.

Glycemic Index Chart
Glycemic Index chart

Why Do We Need Carbs?

Who doesn’t love a carb? Our bodies crave them for good reason. Carbs are one of the most important sources of energy for our bodies and are a key fuel to power our brain. And they make us feel good!

Carbohydrates take two forms, namely starches (such as potatoes, cereals, bread, and pasta); and sugars, such as table sugar (sucrose), milk sugar (lactose), and fruit sugar (fructose). When digested, the starches and sugars in carbohydrates are broken down into millions of glucose molecules that are released into the bloodstream.

When blood glucose levels rise, your body releases a hormone called insulin, which allows glucose to enter cells. Insulin also plays a key role in fat storage: When insulin levels rise, our cells are forced to burn glucose rather than fat. Did you just have that AHA moment? It’s not about starving your body of the nutrients it needs, it’s all about the ups and downs!

There is often a misconception that low GI is low carb.

This is not true. Low carb looks at the quantity of carbohydrates in a food whereas low GI looks at the quality of the carbohydrate, and how your body responds to it.

Good carbs (or low GI carbs) are broken down slowly, trickling a steady supply of fuel into your tank. As well as sustained energy, low GI carbs are naturally more filling helping you feel fuller for longer and not overeat.

On the other hand, high GI carbs can cause your blood sugars to soar and then come crashing down, leaving you feeling flat and can trigger hunger. It’s like taking a rollercoaster ride. This sudden rise in in BGLs puts pressure on your body to produce more insulin, which over time can lead to Type 2 Diabetes and other health complications.

Carbohydrates are important because they are:

  • A universal fuel for most organs and tissues in our bodies.
  • The primary fuel source for our brain, red blood cells and a growing fetus.
  • The main source of energy for our muscles during strenuous exercise.

Carbohydrates are also used for:

  • Genetic material. Sugars form the structural framework of RNA and DNA (ribonucleic acid and deoxyribonucleic acid).
  • Giving certain proteins their functionality. For example, glycoproteins are proteins with carbohydrate attached, which then allow cells to communicate with each other.



People Living With or at Risk of Diabetes Do Not Need to Avoid Carbs!

Diabetes Canada, the Canadian and US Food Guides minimum amount of carbohydrate recommended is 130g per day based on energy and glucose requirements of our central nervous system.

The recommend carbohydrate foods make up 45-65 per cent of your daily energy requirements (roughly 225-310 grams per day), with protein comprising 15 – 25 per cent and fat 20 – 35 per cent.

For people living with or at risk of diabetes, this will also depend on your diabetes medication as well as your individual carbohydrate recommendations.

Highly active people should eat more carbohydrates, and those with a sedentary lifestyle should keep consumption to the lower end of the recommended daily intake.

We recommend you consult an Accredited Practising Dietitian to get tailored dietary and food advice particularly on how best to manage your diabetes, blood glucose levels and carb quantities.

It’s Not Your Fault!

Ever wonder why you keep heading back to the snack cupboard when you know you’re not really hungry? It’s not a question of willpower, it’s simple science.

Levels of the feel-good hormone serotonin – which affects our mood, energy levels and appetite rise and fall depending on many things such as the seasons during the year. Think of how good you feel with the sun shining compared to a cold and rainy day.

Eating carbs increases serotonin levels, so carb cravings are a way of our body trying to increase serotonin levels and make us feel happy. So don’t cut the carbs entirely, just be choosy about swapping to healthy low GI choices. Low GI carbs stimulate the production of serotonin, helping to elevate mood without the negative side effects of high GI carbs and they help keep your energy levels stable, promote satiety and satisfaction as well as improve your cognitive functions.