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Kilojoules explained

Energy in versus energy out

Nearly everything we eat and drink gives our bodies energy. This energy is the fuel our bodies need to function.

How is energy measured?

The energy we get from food and drink is measured in kilojoules (kJ). This is the metric term for calorie. Kilojoules and calories represent the same thing.

One calorie is about four kilojoules. You can easily convert from calories to kilojoules or vice versa.

Different foods and drinks contain different amounts of kilojoules, depending on:

  • the ingredients
  • how the food or drink is prepared
  • size of the serving.

If we eat or drink more kilojoules than our body uses, the spare energy is stored as fat and we will put on weight.

Keeping a healthy weight means balancing how many kilojoules we eat and drink, with the energy we use.

Our daily needs

8700kJ is the average daily energy intake for an Australian adult. It’s the total amount of energy we get from all food and drinks consumed over a whole day.

Because this is an average, calculated across all adult men and women of various ages and activity levels in the population, not everyone needs 8700kJ per day – different people need a different number of kilojoules.

How many kilojoules a person needs each day differs, depending on your:

  • age
  • sex
  • body size
  • activity level
  • life stage (for example pregnancy).

Find out how many kilojoules you need each day. We can also find out how many kilojoules we actually eat in a day.

Kilojoules and weight

Eating and drinking fewer kilojoules and/or being more physically active each day can help us reach or keep a healthy weight. If we are already overweight, this can also help prevent us from putting on more weight.

Not sure how many kilojoules you are burning on that walk, looking after the kids or that basketball game? Get the lowdown on how to burn your kilojoules.

Healthy food and drink choices

The table below shows us how our healthy food and drink choices can make a big difference in the number of kilojoules we eat. And remember, the healthier choices are not only lower in kilojoules, but they are higher in vitamins, minerals and fibre and lower in salt, added sugar and saturated fat.

By regularly swapping some high kilojoule options for healthier, low kilojoule ones, we can cut down our energy intake and lose weight.

kilojoule food table of a high kJ day and a low healthier kJ day

Kilojoules on display

Did you know that from February 2013, all larger food and drink chains in South Australia have been required by law to clearly display the kilojoule information for the food and drink they sell?

Outlets are be required to display the statement that “the average adult daily energy intake is 8700kJ”.

This information makes it easier for us all to make healthier food and drink choices at major takeaway outlets, coffee, bakery, drink and restaurant chains.

Find out how many kilojoules are in particular food and drinks before you head out to eat.

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