We get energy to fuel our bodies from the foods and drinks we consume. Eating more or less kilojoules than our bodies need can result in weight gain or loss.
What are kilojoules (or calories)?
In Australia we measure energy in kilojoules (kJ). Calories (cal) is another word for energy, but kilojoules (kJ) is more commonly used in Australia (1 cal is equal to 4.2kJ).
Are kilojoules bad?
No, our bodies need energy to function properly. However, if we eat and drink more energy than our body needs, the extra energy is stored as fat. If we keep doing this day after day, it can lead to weight gain.
Balancing "energy in, energy out"
To maintain a healthy weight, we need to balance the amount of energy coming in (from food and drink) with the energy going out (how active we are).
The amount of energy in a food or drink will change depending on:
Generally, the more processed a food is, the more energy it contains.
Fresh foods (including fruits, vegetables, breads, cereals, lean meats, milk and milk products) are high in nutrients and relatively low in energy. That's why these foods are great to eat every day.
Some high energy foods, like those with ‘healthy' fats, e.g. avocado and nuts, are good for our bodies. These foods are part of a healthy balanced diet and should be eaten frequently.
How many kilojoules do I need?
Gender, age, height, weight and how physically active you are affect how much energy our bodies need, so rather than counting the kilojoules, focus on the food or drink you are choosing and if it provides nutrients our bodies need.
To have a healthy diet without counting kilojoules, focus on eating a wide variety of nutritious food from each of the food groups: fruits, vegetables, breads and cereals, reduced fat milk and milk products, and lean meat and protein.
Look at the Australian Guide to Healthy Eating for serve sizes of each of the food groups and to learn more about the core food groups and the important nutrients they provide.