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Fullness, thirst

  1. Apr 11, 2005 #1
    What does a feeling of fullness (hunger-wise) mean? Does it mean that you have consumed all that yor body wants to eat right now? Does it mean that further consumption will be in excess and end up as waste or fat?

    What does a feeling of thirst mean? Does it mean that your body needs more fluids? I drank about a gallon of water once and peed a lot after that (clear urine)...does this mean that a person can only consume so much and the rest is waste?
  2. jcsd
  3. Apr 11, 2005 #2


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    No, its more basic than that. Its very much like the auto-shutoff on a gas pump: when it senses that the gas tank is full, it shuts off. You feel full, quite literally, when your stomach is full.

    I can't answer the mechanism of feeling thirsty, but:
    Yes, excess water is just discarded.
    Last edited: Apr 11, 2005
  4. Apr 11, 2005 #3
    A feeling of fullness normally means your endorphins have kicked in. It takes about 20 minuets from the time you start eating for this effect to be felt. So if you eat very slowly, your body will tell your brain your full, even if you haven't eaten as much as you normally would.
  5. Apr 11, 2005 #4


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    Well, it depends on what you mean by feeling "full." There is the mechanical stretching of your stomach, which generally means you've already eaten too much, which is what Russ is talking about. Then there is a feeling of satiety, which is a hormonal response to the nutrients being absorbed, which is what hypatia is talking about. As hypatia pointed out, eating more slowly gives your body more time to respond to what you've eaten so you get that satiety signal before you get the "full" signal. If you are eating until your stomach is distended and sends you that uncomfortable full signal, you're probably overeating. One area of obesity research involves understanding the satiety mechanism and why some people don't seem to experience satiety before overeating.

    I have to go make a phone call so can't stay on and look up some sample references for you right now, but in terms of satiety, you can look up information on the hormones leptin and adiponectin to get started. Insulin is also of course well-known.

    As for thirst, just one note, which is that if you frequently find yourself feeling very thirsty and then urinating frequently as well, you should see a physician to get tested for diabetes. If that was just a one-time thing where you gulped down a gallon of liquid after doing something that makes sense to have dehydrated you a bit (after a workout for example), then don't worry.
  6. Apr 11, 2005 #5
    No, its not diabetes, I drank all that to test if I'd pee it all back out. I guessed that I would and I was right.

    So, if you experience satiety or stomach stretching but keep eating, are the nutrients from that food still absorbed?
  7. Apr 11, 2005 #6


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    We aren't 100% efficient at absorbing all the nutrients in the first place, so no, some are going to be lost and just excreted, probably moreso if you overeat and your body isn't used to it. But, a lot of the nutrients will be; that's how you gain weight from overeating, by absorbing the nutrients in the food. Depending on the nutrients, you'll convert the excess into fat for storage.
  8. Apr 12, 2005 #7
    You may have wondered why I am asking this.

    Have you ever had a parent say "Clean your plate, don't waste food" even when you are very full?

    I am looking for a logical reason why 'cleaning the plate' may not be the best choice. So if a child is feeling full from a meal and still has, say, mashed potatoes and ham left...chances are he won't be any healthier by finishing it versus throwing it away. Is this correct? Could, through gaining excess fat, the child become less healthy by 'cleaning his plate'?
  9. Apr 13, 2005 #8
    anyone know?
  10. Apr 13, 2005 #9
    You should let children eat only until they feel full.
    My kids didn't like cooked veggies and would suddenly feel full{smirk}, so I gave them there dinner in stages. In this order Milk or juice, salads/fruit, veggies, meats/cheese{protein} and then starches.
    If they got hungry later on, they could pick up where they left off, but only when they finnished eating a balanced diet could they have sweet treats
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