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Where does human`s weight go?

  1. Mar 18, 2007 #1
    Hello!
    I wonder if you know answer for my question:
    Where does human`s weight go during tabescence. Imagine, that you won`t drink or eat fro 5 days. You will be losing your weight. However it does not change to energy because the efficienfy of burning proceses in human body goes to 0%!
    So here da hell the weight goes? Is it possible to count up how many kilos I will lose during the 5days diet?

    Would you be so king and answer my questions, if possible?
    Thank you a lot for you questions!
     
  2. jcsd
  3. Mar 18, 2007 #2

    Danger

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    Welcome to PF, Xombox. A lot of that energy does get expressed as heat, even if it's just to maintain the body's core temperature (as opposed to that released from muscles during normal activity). As far as other mass goes, consider how much water vapour is exhaled with every breath... not to mention the fact that your bathroom functions continue. One of our resident biologists can fill you in much more.
     
  4. Mar 18, 2007 #3
    Thank you for your fast answer, Danger! Yeahh, I am new at PF but my first feeling is a good one. You welcomed me kindly ;)
    I will look trough internet to find some facts about water exhaleting and maintaining the body`s temperature and I will try to count some numbers out :-)

    I would be glad if biologists help me.
     
  5. Mar 18, 2007 #4

    AlephZero

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    When "the efficiency of the burning process" goes to 0%, you are dead :uhh:

    As well as losing water vapour, you are breathing in oxygen and breathing out carbon dioxide. Where do you think the the carbon atoms in the CO2 come from?
     
  6. Mar 18, 2007 #5

    Danger

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    Your first feeling is the same as mine was a couple of years ago. This is an incredibly supportive community, dedicated to helping anyone who is in search of scientific answers. While I'm proud to occassionally contribute some useful input, I've learned far more here than I ever did in the previous 49 years.
    Keep hanging around, and you'll realize just how special this place is. Evo or MIH should be around soon to smack you upside the head with the 'welcome' fish, but you might have to go down to General Discussion for it.
    As for the promptness of my response, it's actually just because I got up for a midnight beer. Since this is an international community, we occupy every time zone on the planet. If you occassionally have to wait a few hours for a response, it's probably because everyone is asleep or at work. Patience is required.
    And again, welcome.

    edit: Oh, hi Aleph. You sneaked in while I was composing.
     
  7. Mar 18, 2007 #6

    AlephZero

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    But anyway, not eating for 5 days won't harm you much if you are normally healthy to start with, but not drinking for 5 days is a very dumb idea.
     
    Last edited by a moderator: Mar 18, 2007
  8. Mar 18, 2007 #7

    Moonbear

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    As long as you are alive, you are burning energy to stay alive. Initially, you will use fat reserves to provide the energy to maintain muscle function and vital organ function (respiration, heart rate, liver, brain, etc.). If you have used up your fat reserves, then your body will begin breaking down muscle mass in a last ditch effort to preserve vital organ functions (circulation and respiration, brain function).
     
  9. Mar 18, 2007 #8
    Then Moonbear, at what stage or situation will the brain stops the heart in order to preserve itself?
    I know I've read this somewhere..
     
  10. Mar 18, 2007 #9

    Moonbear

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    Death...you don't live very long if your heart stops. :uhh:
     
  11. Mar 18, 2007 #10
    I know that, But I've read that in deprivation of (something), the brain as a last attempt will stop the heart in order to preserve itself (or in order to receive more of that thing), only to die in few minutes itself.
    But I totally forgot what's that "Something".
     
    Last edited: Mar 18, 2007
  12. Mar 18, 2007 #11

    Moonbear

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    Seriously, think about that for just a few moments and tell me if you think that makes any sense at all.
     
  13. Mar 19, 2007 #12
    lol, sometimes people doesn't realize how stupid what they are asking, sorry.
     
  14. Mar 19, 2007 #13

    Moonbear

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    No problem, just wanted to make sure you stopped and thought about the question.
     
  15. Mar 21, 2007 #14

    adrenaline

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    The person will lose most of her weight in the first few days to weeks in terms of insensible water losses. Insensible fluid losses are the transepidermal diffusion water that passes through the skin and is lost by evaporation and evaporative water loss from the respiratory tract as someone else already mentioned.


    ( In medicine we call it insensible because we don't feel it).

    Daily loss is about 400 mls in an adult from the adult ( unstressed not excercising and sweating it off, if you have a fever that goes up of course which is why febrile patients get dehydrated)

    Insensible loss from the respiratory tract is also about 400 mls/day in an unstressed adult. The water loss here is variable: it is increased if minute ventilation increases and can be decreased if inspired gas is fully humidified which is why we humidify ventilated ICU patients.

    So that is 800ml almost a liter a day in a unstressed adult just sitting there.



    Thus this non eating non drinking person will lose almost a liter ( 1000grams of fluids a day,) (that's not taking into account peeing and pooping etc.) and since a liter of water is 2.2 pounds.....and I am too lazy to convert 800 grams to pounds ...... well, you can see how much water weight she will lose quickly!

    Of course as she continues to starve her body starts to cannabolize itself and her weight loss will increasingly be due to loss of muscle and fat mass.
     
    Last edited: Mar 21, 2007
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