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 sugary foods like ice-cream, biscuits, soft drinks and cakes.
What is glycaemic index (GI)?
When we eat carbohydrates, our digestive system breaks them down into simple sugars – mainly glucose. Our cells use this glucose to produce energy.
Carbohydrates break down into glucose at different rates. This means that different carbohydrates – that is, different foods – cause glucose levels in our blood to go up and down at different rates.
The glycaemic index (GI) measures the effect that carbohydrates in food have on blood glucose levels. GI ranks foods on a scale from 0-100:
- Foods with a low GI (0-55) cause a steady and long-lasting rise and fall in blood glucose levels. This is because the carbohydrates in these foods break down slowly.
- Foods with an intermediate GI (56-69) cause a moderate rise and fall in blood glucose because their carbohydrates break down at a moderate rate.
- Foods with a high GI (70-100) cause a large and fast rise and fall in blood glucose. This is because the carbohydrates in these foods break down quickly.
Foods and GI
The following is a guide only to some foods and their GI values. 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.
Low-GI foods (GI of 55 or less)
Intermediate-GI foods (GI between 56 and 69)
High-GI foods (GI of 70 or more)
Low-GI symbolWhen you’re looking for low-GI food, it’s also a good idea to look for the Glycemic Index Foundation’s Low-GI symbol. Many foods are now marked with this 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.
Benefits of low-GI food
Low-GI foods are good because they give your child longer-lasting energy, which can help him concentrate better and keep him going for longer.
If your child does endurance sports like long-distance running, low-GI foods help keep her energy levels up.
Low-GI foods also keep your child feeling fuller for longer. This can help him maintain a healthy weight.
Using GI to plan healthy family eating
As well as making sure your family eats plenty of fresh food from the five healthy food groups, it’s 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 are generally healthier than high-GI foods. This is because low-GI foods make blood glucose (sugar) levels go up and down slowly and steadily. This means your child is fuller for longer, so she’s less likely to snack between meals and overeat.
It’s OK to eat some high-GI foods occasionally. 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 impact 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 carbohydrates across the day.
This keeps your child’s blood glucose levels stable and his 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.
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.
By swapping 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 low GI like Weet-Bix® or All Bran®
- 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
- tropical fruits – for example, watermelon – for cooler-climate fruits like apples, lady finger bananas, pears, peaches, grapes, nectarines, oranges and mandarines
- white potato 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.
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 he enjoys.
You can try to:
- 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 she 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 – will give your child sustained energy on the day of the game.
GI and diabetes
If your child has type-1 diabetes or impaired glucose tolerance, his blood glucose levels might rise above a normal level more quickly than other people’s.
Eating low-GI foods can help your child manage her blood glucose levels. And eating moderate amounts of low-GI foods regularly over the day will help her 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 his eating.