By Amanda Salis, University of Sydney
Dietary guidelines broadly recommend a daily intake of 10,000 kilojoules (2,400 calories) for men and 8,000 kilojoules (1,900 calories) for women.
But what do these figures mean in the context of the number of kilojoules or calories you personally need to maintain a healthy body weight?
I’m going to stick with kilojoules in this article because kilojoules – not calories – are the metric unit for measuring energy, just as kilograms – not pounds – are the metric unit for measuring body weight.
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Daily kilojoule requirements are based on many variables, and no two people are the same across all of these parameters.
It makes sense then that if we all followed the same prescriptions for kilojoule intake, some of us would gain weight while others might lose some.
That’s because any excess or deficit between the number of kilojoules you consume and the number your body uses results in weight gain or loss.
So how can you know what you need to maintain your energy balance? There are two options: the mathematical approach, which requires kilojoule counting, and the instinctive approach, which involves “listening” to your body (my personal preference).
Both approaches take some trial and error.
The mathematical approach
One way to estimate how many kilojoules you need is to use an online calculator that takes into account major factors regulating energy requirements. These include your sex, weight, age and activity levels. Some calculators also take height into account.