What are Kilojoules?

Medilia
Medilia Posts: 230 Member
in Food and Nutrition
What are Kilojoules? I have been noticing them listed on cafe and fast foods.

Replies

  • krickps
    krickps Posts: 3 Member
    Kilojoules (kJ) are the metric equivalent of kilocalories (what most of us just call Calories). There are aproximately 4.2kJ per kilocalorie.
  • spersephone
    spersephone Posts: 148 Member
    It's like the metric version of calories. I'm in Australia, but I've always worked in calories. When I see a packet which only lists kj, I have to divide it by 4.2 to work out the approximate calories.
  • pinkraynedropjacki
    pinkraynedropjacki Posts: 3,027 Member
    KJ's are a pain in the *kitten*. I hate having to have a converter on my phone just to know if I should buy it. I hate the fact we still list in KJ but everything in the world is Cal....
  • NanoBear
    NanoBear Posts: 67
    All food in Australia has to have it listed in KJ by law. A lot of things don't have cal on the label. But then, having gone though maths, physics and chemistry in school and uni in Australia, I find it easier to think in KJ anyway.

    Out of interest, an actual calorie is the energy required to heat 1 gram of water by 1 degree celsius
    What people refer to as calories in food is actually kilocalories, where 1 Kcal is the energy required to heat 1kg of water by 1 degree celcius.

    1 Joule is the energy expended to apply a force of 1 Newton through a distance of 1 meter. Sounds more complicated, but it makes a lot more sense than calories in physics.

    Joules and kilojoules are the international standard in science. Calories are really only used for food and some areas of chemistry.
  • Medilia
    Medilia Posts: 230 Member
    Thanks! That will make it so much easier for me when I go out to eat. I am working for calories for the most part but when I am out I can just convert it all

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