Kilojoules, calories and the energy we get from food

Your daily kilojoule needs

‘Calories’ is another measure for energy, but in Australia we use kilojoules.

Getting enough energy and physical activity each day can help you stay healthy and reduce your risk of some diseases. It can also help you achieve and maintain a healthy weight.

Everyone is different and many things can influence your health. Knowing more about how much energy your body needs is one way to support your health and wellbeing. This is because it can help you make healthier decisions about the kinds of food you eat and drink and create habits that are right for you.

On average, adults need 8,700kJ a day from all foods and drinks. However, your energy needs will depend on things like:

• how much physical activity you do, and what type 

• your height, weight, age and sex

• whether you are pregnant or breastfeeding 

• genetics

• overall health and health conditions.

Getting too many or not enough kilojoules can affect your overall health and wellbeing, including your weight. For good health and wellbeing, aim to eat foods from the 5 food groups and be active every day if you can.

Find ideas for healthy meals in our healthy recipe library. 

Kilojoules and physical activity

Your body uses energy all day – even while you sleep. When you’re active, your body uses up more energy.

If you eat or drink more kilojoules than your body needs, the extra energy can lead to weight gain.

Regular physical activity can help you maintain a healthy weight and good health. It can also reduce your risk of some diseases and support your mental health. 

Learn more about how much physical activity to aim for to support good health and wellbeing. 

Kids and kilojoules

Every child is different, so there is no exact number of kilojoules your kids should eat each day. Your child's energy needs depend on how active they are, whether they’re having a growth spurt, and their age and sex.  

Children know whether they are hungry or not. If they have been using energy being active, they may be more hungry than usual. Encourage them to tell you when they are feeling hungry or when they are full at meal or snack times. 

For ideas to help your kids stay healthy and thrive, check out our guides on:

• healthy eating for children 

• healthy screen use

• physical activity for children

• sleep and children’s health.

You can also support your child by role modelling and trying to build healthy habits into your day.  

How to check the kilojoules in your food and drinks

The kilojoules in your food depend on its ingredients, how it has been made and its serving size. Most packaged foods and fast food outlets display kilojoules on packages and menus. 

Kilojoules are not the only thing to look for when you’re trying to make healthy choices. Something low in kilojoules might not be ‘healthier’ for you overall. For example, nuts are high in kilojoules but also have nutrients that support good health, so they are part of the 5 food groups. Diet soft drinks are low in kilojoules but don’t have any nutrients, so they’re not part of the 5 food groups.

Here are some ways to help you make healthier choices around food and drinks.

• Look for the Health Star Rating on packaged food and choose options with at least 3.5 stars. Vegetables and fruit may not have a package, but they score top marks – 5 stars.

• Learn how to read labels on packaged foods to check ingredients, kilojoules, and portion size.

• Look closely at the ‘number of servings’ on packaged food as the package could have more than one serve in it.

• Remember, drinks contain energy (kilojoules) too. Some drinks are surprisingly high in kilojoules. We often don’t realise how many kilojoules we get from drinks because they’re not as filling as food.  

Kilojoules and eating out

When you’re eating out at a restaurant or getting takeaway, you might see kilojoules listed beside items on the menu. These can help you compare meals at takeaway stores, and fast food and quick service restaurants. You can use this information to make healthier choices about what you eat and how often you eat it. 

When you’re eating out, try to limit fried foods, pastries and soft drinks as these can be high in kilojoules. Instead, look for meals that contain foods from the 5 food groups. This will help you and your family stay healthy.  

Learn more about choosing healthier takeaway and homecooked meals and snacks.