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Medical Gaining weight

  1. Sep 17, 2011 #1
    I thought about what gaining weight means. Isn't the following (obviously) correct?

    When you eat X grammes of something you momentarily gain X grammes of weight. The only way to lose weight is to go to the toilet or sweat. However, when you sweat most of the mass is water so this is easily calculable.

    Now it's probably quite doable to calculate which part of the food mass stay in the body after the first digestion cycle. The rest is weight gain. Unless it is decomposed again and "flushed" away.

    Does that makes sense? Have I missed something? It seems more direct than calorie thinking.
    Shouldn't it be easy to directly calculate the mass you lose when you exercise? Like this biochemical process will transform mass into waste mass.
  2. jcsd
  3. Sep 17, 2011 #2


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    Staff: Mentor

    How much the food weighs has nothing to do with storing excess calories (turning them into fat) and gaining weight. The weight of food is not a consideration. This is why you should weigh yourself in the morning, after you have a bowel movement, preferably. This will give you your most consistently accurate weight. Of course during the day your weight goes up and down slightly as your body removes solid and liquid waste that you've consumed.
    Last edited: Sep 17, 2011
  4. Sep 17, 2011 #3


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    Staff Emeritus
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    Gaining weight is very simple, it is simply an increase in weight. So yes if I ingest a dinner then I am heavier. In the context of medicine gaining weight is looked at over time to smooth out the anomalies like this, there's little need to try and work out the exact percentage gained from each meal. And remember calories are a very sloppy way of measuring things like this because they are only a measure of the energy given off by food when it is literally burnt. They say nothing about metabolism.
  5. Sep 17, 2011 #4


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    Staff: Mentor

    LOL, I do have the English Bible of Food knowledge from 1902.


    This makes calories seem so much simpler. :biggrin:
  6. Sep 17, 2011 #5
    if you're trying to change the amount of tissue you carry (fat/muscle/etc), you'll get a lot better results if you track calories in versus calories out. that is, how much you eat in calories versus how much you expend in activities as calories. food and excretion mass is not a very reliable way, as much of food is water mass, and good luck tracking something as variable as how much water you lose in sweat and breathing. as mentioned above, just track a moving average of your morning weight and focus on that trend, as well as your measurements and visual results (assuming you aren't body-dysmorphic).
  7. Apr 10, 2012 #6
    weight gain is only happen when you eat more calories and burn less calories. The difference of these result is weight gain. And when you do some work out there are increase in body weight. It is true that body weight increase and decrease in a day with the increase in working routine. Total weight gain is the equal of calories and body work out in a day.
  8. Apr 10, 2012 #7
    That's only a rule of thumb and here I wanted to encourage deeper self-thinking.
    Physically you only gain weight if you eat something. Obviously, drinking 1l of water makes you weight increase by 1kg. Try it out yourself!
    Burning calories does absolutely nothing until you lose mass by exhaling, sweating or visiting the bath room. And work out only transforms mass and does nothing to your weight until you notice that some mass you ate is not going to be "emitted" again due to being bound in muscles.
    Calories have no mass. However, you can probably convert them to mass by assuming that calorie intake corresponds to a particular type of ingredient.

    So my question is basically to understand the process of gaining weight from the fundamentals and identify where most weight is lost (breathing, sweating, toilet).
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