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Thread: Does water contain calories?

  1. #1 Does water contain calories? 
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    I've heard that unless water is at -470 degrees F (roughly), it actually does contain a small amount of calories because of the heat in the water. Does anyone have any comments on this? Is it right or just something I heard? I'd really appreciate any feedback I can get. Thanks.


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  3. #2  
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    You have to be more specific about your phrase "contain calories."

    It means something different to the food scientists or nutritionists than it does to physicists or anyone else who is not concerned about gaining weight.

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    It would contain a higher kinetic energy(so therefore higher joules/calories) the higher the temperature, but the human body wouldn't be able to utilize that through the stomach.
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    ................. I think your friend is making the assumption that an energy value given in calories implies food.
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  6. #5 thanks for the feedback 
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    I bring this up because a discussion I had with my teacher who said exactly that. I know food calories are measured in kcal so perhaps I misunderstood him. However, it seems like a correct assumption. Thanks for the feedback.
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    If you drink cold water then expel it at a higher temperature, it will absorb some heat that will be replaced by burning food calories. In that way, there is some equivalence. But that only amounts to one food calorie (kcal) per kilogram per degree centigrade of temperature change.
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  8. #7  
    Forum Ph.D. GhostofMaxwell's Avatar
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    If you think about it though its not an entire wast of time: If you drink 5 litres of ice cold water a day and your body has to raise it 20 oC each time. Thats 100 kcals and there will surely be inefficiencies in the process. That amounts to about a bag of Maltesers doesnt it?
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  9. #8 hello there 
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    "calorie" is a measurement of energy. In a biochemist point of view it is the amount of energy in a molecule that can be utilized when a particular molecule is fully catabolized. There are no mechanisms in the human body to catabolize H2O. So in that sense, it doesn't contain any utilizable calories.
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  10. #9  
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    Quote Originally Posted by GhostofMaxwell
    If you think about it though its not an entire wast of time: If you drink 5 litres of ice cold water a day and your body has to raise it 20 oC each time. Thats 100 kcals and there will surely be inefficiencies in the process. That amounts to about a bag of Maltesers doesnt it?
    I think you're mixing up a joule and a calorie. I believe it only works out to be something like 5 kcal/liter of water.
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  11. #10  
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    Quote Originally Posted by Scifor Refugee
    Quote Originally Posted by GhostofMaxwell
    If you think about it though its not an entire wast of time: If you drink 5 litres of ice cold water a day and your body has to raise it 20 oC each time. Thats 100 kcals and there will surely be inefficiencies in the process. That amounts to about a bag of Maltesers doesnt it?
    I think you're mixing up a joule and a calorie. I believe it only works out to be something like 5 kcal/liter of water.
    No!
    1 cal raises a millilitre 1 oC
    1kcal raises a litre of water 1oC
    x20 =20 kcal for 20o raise
    x5=100kcal for 5 litres
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  12. #11  
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    Definitions from Wikipedia:
    # The small calorie or gram calorie approximates the energy needed to increase the temperature of 1 gram of water by 1 °C. This is about 4.184 joules.
    # The large calorie or kilogram calorie approximates the energy needed to increase the temperature of 1 kg of water by 1 °C. This is about 4.184 kJ, and exactly 1000 small calories.

    As GhostofMaxwell says, that's 20 large calories per kg for a 20 degrees C delta T, and 100 per 5 kg. A liter of water is a kilogram.
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    Never mind, I was the one mixing them up.
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  14. #13  
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    I would think that water contains calories in its bonds, but as someone stated earlier, the body never does anything to break those bonds and use the energy, so when we drink it, it effectively doesn't impart any calories to us.
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  15. #14  
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    I am pretty sure that we cannot break down water, but in our bodies we do synthesize water. Oxygen is the final hydrogen acceptor in the electron transport chain during cell respiration. I pretty much agree we don't gain any coloric value from water, it actually may cause a coloric deficit in that we rarely drink anything that is 98.6? farenheit. Also I have to point out that a calorie is measured by how much a mL of water temperature raises while something is burned. Though hypothetically how much energy could we take from water if we did have the mechanism to break it down?
    Why is hate so ingrained in humans? For the supposed enlightened species we are very limited to such primitive behaviors. Peace is a fleeting in our society.
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