What is the glycaemic index (GI)?

The glycaemic index (GI) ranks carbohydrate foods by how quickly they break down into glucose and raise blood glucose levels. A food’s GI tells us how quickly our bodies get energy from that food.

The GI ranks foods on a scale from 0-100. The lower the ranking, the lower the GI.

What are carbohydrates?

Carbohydrates are natural complex sugars made up of simple sugars joined together.

Our bodies get energy from carbohydrates by breaking them down into simple sugars like glucose and fructose. These simple sugars are released into our bloodstreams for our bodies to use as energy or to store in our muscles and liver for later use.

Sources of carbohydrates

• Starchy foods like bread, pasta, rice, cereals and potato
• Fruit and vegetables
• Dairy products like milk and yoghurt
• Table sugar and honey
• Foods with added sugar, like ice-cream, biscuits, soft drinks, puddings, slices and cakes

Healthy eating for children means eating a wide variety of fresh foods from the 5 food groups. GI is something you can consider when you’re choosing healthy food for your child. Low-GI foods can have benefits when they’re part of a healthy diet overall.

What are low-GI foods?

Low GI-foods have a ranking of 0-55.

Low-GI foods provide steady, long-lasting energy. This is because the carbohydrates in these foods break down into glucose slowly, causing a steady and long-lasting rise and fall in blood glucose levels.

Benefits of low-GI foods for kids and teens

If your child has plenty of foods from the 5 healthy food groups each day, they can get additional benefits if some of those healthy foods are also lower-GI foods:

• If your child eats more low-GI foods than high-GI foods throughout the day, it’ll help your child concentrate better and keep going for longer.
• Lower-GI foods might keep your child feeling fuller for longer. This can help your child stay at a healthy weight because your child is less likely to snack on unhealthy foods.
• If your child does endurance sports like long-distance running, low-GI foods can help to keep up their energy levels.

Examples of low-GI foods

• Barley, bran, quinoa
• Basmati rice, Doongara rice, black rice
• Pasta, pearl couscous
• Dense wholegrain bread, paratha
• Natural muesli, traditional oats
• Carisma potatoes, vegetables
• Cherries, grapefruit, pears, apples, grapes, most berries
• Lentils, beans, chickpeas
• Nuts
• Milk, yoghurt

How the GI symbol can help you choose food

The GI symbol can help you know whether a food is genuinely low GI.

Foods with the Glycemic Index Foundation’s GI symbol must be low GI and meet strict standards for kilojoules, saturated fat, sodium and, where appropriate, fibre and calcium.

What are intermediate-GI foods?

Intermediate-GI foods have a ranking of 56-69.

These foods cause a moderate rise and fall in blood glucose. This is because the carbohydrates in these foods break down into glucose at a moderate rate.

Examples of intermediate-GI foods

• Arborio rice, long grain rice
• Rice noodles, buckwheat noodles
• Pita bread, wholemeal bread
• Some breakfast cereals including Weet-Bix
• Mango, ripe banana, pineapple, kiwi fruit
• Soft drink
• Sweet biscuits, cakes

What are high-GI foods?

High-GI foods have a ranking of 70-100.

These foods cause a large and fast rise and fall in blood glucose. This is because the carbohydrates in these foods break down into glucose quickly.

Examples of high-GI foods

• Most highly processed breakfast cereals including flaked corn and puffed rice
• Most potatoes (unless boiled and cooled)
• Melons
• Hot chips, French fries, lollies, most crackers, savoury snacks
• Jasmine rice, sticky rice, congee, white bread, naan
• Sports drinks, energy drinks

Different varieties and brands of food have different GI values. It’s best to look for the Glycemic Index Foundation’s GI symbol or speak to a dietitian for more information.

How to use GI to plan healthy meals for your child and family: tips

The first step to healthy eating for your child and family is choosing plenty of fresh food from the 5 healthy food groups. You can also think about GI when you’re planning what your family will eat.

Aim for healthier choices across the GI spectrum

It’s important for your child to have low-GI food at each meal and snack. It’s also OK for them to have intermediate-GI foods and high-GI foods, especially if they’re healthier choices.

Low-GI foods and high-GI foods combine in your child’s body for a medium GI overall – they can balance each other out.

Consider glycaemic load (GL)

Glycaemic load (GL) measures the quality – the GI – and quantity of carbohydrate in a serving of food.

GL accounts for the fact that the amount of carbohydrate in food affects blood sugar levels too, and that a low-GI food can sometimes cause a larger rise in blood sugar than a high-GI food.

For example:

• Watermelon has a high GI, but a standard serve doesn’t have much carbohydrate, so it has a low GL.
• Basmati rice has a low GI, but a standard serve has a lot of carbohydrate, so it has a high GL.

This means that a standard serve of Basmati rice will cause a larger rise in blood sugar than a standard serve of watermelon.

Spread carbohydrates across the day

As a general guide, it’s good for your child to have 3 regular meals and some nutritious snacks each day. This way, your child gets an even spread of energy from carbohydrates across the day, which helps to keep their blood glucose and energy levels steady.

It’s always best to consider a food’s overall nutritional value before looking at its GI rank. Low-GI foods are generally a better choice than high-GI foods, but not always. For example, chocolate has a lower GI than rockmelon. But rockmelon is a healthier choice because it’s packed with essential nutrients, whereas chocolate is high in saturated fat.

How to make the change to lower-GI foods

Choosing lower-GI foods is easy. And there’s a good chance your family won’t notice the difference.

If you can make at least half your carbohydrate food choices lower-GI options, it can be good for your whole family.

Easy swaps

• Choose multigrain breads, paratha, pita bread or genuine sourdough bread instead of naan or white or wholemeal bread.
• Choose unrefined breakfast cereals like porridge with rolled oats, All Bran, Special K or Weet-Bix instead of processed breakfast cereals like porridge with quick oats, Rice Bubbles or Corn Flakes.
• Choose biscuits made with dried fruit and wholegrains instead of plain biscuits and crackers.
• Choose cakes and muffins made with fruit, oats and wholegrains instead of other cakes and muffins.
• Choose low-GI potatoes like Carisma or sweet potato, corn, pasta or legumes instead of white potatoes.
• Choose Basmati, Doongara or black rice instead of most other rices.

Some foods with a lot of fibre can slow the breakdown of carbohydrates, giving it a lower GI. By choosing high-fibre foods like green leafy vegetables and wholegrain foods, you can get your family eating more low-GI foods and meals.

How to encourage your child to eat low-GI foods

Here are ways to encourage your child to eat and enjoy low-GI foods:

• Set a good example and show your child that you enjoy eating many different low-GI foods.
• Offer low-GI foods at meals and encourage your child to taste them. It’s OK if it takes a while for your child to enjoy some new foods and flavours.
• Keep low-GI foods as ‘everyday’ foods and high-GI options as ‘sometimes’ foods.

What if your child has diabetes?

If your child has type-1 diabetes or impaired glucose tolerance, your child’s blood glucose levels might rise more quickly after a meal or snack than people without diabetes.

Eating low-GI foods can help children manage their blood glucose levels. Eating moderate amounts of low-GI foods regularly over the day will help your child keep consistent blood glucose levels.

If your child has a medical condition like diabetes, it’s important to talk with your GP, other specialist or dietitian before making any changes to your child’s eating.