What are carbohydrates?
Carbohydrates are natural substances that contain oxygen, hydrogen and carbon. We need carbohydrates to give our bodies energy – to ‘get up and go’.
We get carbohydrates from:
- starchy foods like bread, pasta, rice, cereals and potato
- fruit and vegetables
- dairy products like milk and yoghurt.
We also get carbohydrates from table sugar and foods with added sugar, like ice-cream, biscuits, soft drinks and cakes.
What is glycaemic index (GI)?
Our bodies get energy from carbohydrates by turning them into simple sugars – mainly glucose.
The glycaemic index (GI) measures how quickly our bodies get energy from carbohydrates. It does this by measuring how quickly different carbohydrates break down into glucose in the body. Different carbohydrates break down into sugars at different rates.
The glycaemic index (GI) ranks foods on a scale from 0-100.
Low GI-foods have a ranking of 0-55. They cause a steady and long-lasting rise and fall in blood glucose levels. This is because the carbohydrates in these foods break down into glucose slowly.
Here are examples of low-GI foods:
- barley, bran, dense wholegrain bread, Doongara rice, natural muesli, pasta, pearl couscous, quinoa, traditional oats
- Carisma potatoes, fruits (except melons), vegetables (except most potatoes)
- milk, yoghurt.
Low-GI foods provide steady, long-lasting energy. This means they have several benefits:
- 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.
- They might keep your child feeling fuller for longer. This can help your child stay at a healthy weight.
- If your child does endurance sports like long-distance running, low-GI foods help keep energy levels up.
When you’re looking for low-GI foods, it’s a good idea to look for the Glycemic Index Foundation’s Low-GI symbol. Foods with the symbol must be low GI and meet strict standards for kilojoules, fat, saturated fat, sodium and, where appropriate, fibre and calcium.
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.
Here are examples of intermediate-GI foods:
- Arborio rice, Basmati rice, long grain rice, wholemeal bread, some breakfast cereals including Weet-Bix®
- soft drink
- sweet biscuits, cakes.
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.
Here are examples of high-GI foods:
- hot chips/French fries, lollies, most crackers and savoury snacks
- jasmine rice, white bread, most highly processed breakfast cereals including flaked corn and puffed rice
- most potatoes
- sport drinks.
Different varieties and brands of food can have different GI values, so it’s best to speak to a dietitian if you’d like more information.
Using GI to plan healthy family eating
The first step to healthy family eating is choosing plenty of fresh food from the five healthy food groups. But it’s also good to think about GI when you’re planning what your family will eat.
Getting a balance of high and low GI
Low-GI foods make blood glucose (sugar) levels go up and down more slowly and steadily than high-GI foods. This means your child is fuller for longer, so they’re less likely to snack on unhealthy options between meals or overeat.
It’s OK to eat some high-GI foods. The trick is to include a low-GI food for your family at each meal and snack.
High-GI foods and low-GI foods combine in your child’s body for a medium GI – they balance each other out.
When you’re choosing which foods to offer your family, it’s important to think about not just the GI rating, but how much of these foods you’re eating – that is, portion size. This is sometimes called the glycaemic load (GL).
A big serving of a high-GI food like potatoes or lollies will have a big effect on your child’s blood glucose levels. So if your child has small serves of high-GI foods and larger, more frequent serves of low-GI foods, this can balance things out.
When to eat your carbohydrates
There’s no hard and fast rule about when to eat carbohydrates, but each day it’s good for your child to have three regular meals and some nutritious snacks. This way, your child gets an even spread of energy from carbohydrates across the day.
This keeps your child’s blood glucose levels stable and energy levels steady. This is essential for adults and children with diabetes, but it’s also important for people who want to keep up good general health.
It’s always best to consider a food’s nutritional value before looking at its GI value. Low-GI foods are generally healthier than high-GI foods, but this isn’t always the case. For example, potato chips often have a low GI, and watermelon has a high GI. But watermelon is healthier because it’s packed with nutrients.
Making the change to low-GI foods
Switching to low-GI food is easy. Chances are your family won’t notice the difference – at least not all of the time.
If you swap at least half your carbohydrate food choices for lower-GI options, your whole family can reap the benefits.
For example, you can swap:
- white or wholemeal bread for multigrain breads, pita bread, or genuine sourdough bread
- processed breakfast cereals like Rice Bubbles® or Corn Flakes® for unrefined breakfast cereals like traditional (not instant) porridge, or cereals with a lower GI like All Bran®, Special K® or Weet-Bix®
- plain biscuits and crackers for biscuits made with dried fruit and wholegrains
- cakes and muffins for cakes and muffins made with fruit, oats and wholegrains
- white potatoes for low-GI potatoes like Carisma™, and sweet potato, corn, pasta or legumes like lentils, beans and chickpeas
- most rices for Basmati, Doongara or Mahatma rice.
Some foods with lots of fibre can help slow the breakdown of carbohydrates, giving it a lower GI. By choosing wholegrain foods or keeping the skin on vegies like potatoes and carrots, you can get your family eating more low-GI foods.
Frequently asked questions about low-GI foods
What if my child doesn’t like low-GI foods?
Not all of your child’s food needs to be low GI. Low-GI and high-GI foods combine to give a medium GI – they balance each other out. Ideally, at least half of your child’s carbohydrates will come from low-GI foods.
Here are some ways you can encourage your child to eat more low-GI foods:
- Set a good example and show your child that you enjoy eating lots of different low-GI foods.
- Keep offering low-GI foods at mealtimes and encourage your child to taste them. It might take up to 10-15 times before your child accepts new foods and flavours.
- Keep lower-GI foods as ‘everyday’ foods and high-GI options as ‘sometimes’ foods.
Chocolate has a low-GI value. Does this make it a good food choice?
Many foods high in fat have a lower-GI value – chocolate is a good example of this. Low GI doesn’t cancel out the problems of high fat – you need to look at the whole food.
So you and your family should try to have foods like chocolate as occasional treats only.
What’s the best food for my child to eat before sport?
Carbohydrate foods are the best source of energy before sport. Low-GI breakfast foods – like traditional porridge, wholegrain cereal or toast – can give your child sustained energy before sport.
GI and diabetes
If your child has type-1 diabetes or impaired glucose tolerance, your child’s blood glucose levels might rise above a normal level more quickly than other people’s.
Eating low-GI foods can help children manage their blood glucose levels. And 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, dietitian or specialist before making any changes to your child’s eating.
There’s no link between eating sugar and developing diabetes. But eating too much added sugar can contribute to weight gain, and being overweight increases the risk of developing type-2 diabetes.