At what point in the digestive cycle do the pounds come off when you're exercising?

Factual Questions
21

[QUOTE]
*Originally posted by PaulT *
**Rusalka: That’s absolutely true – if you stop eating, you will stop defecating. The alimentary canal is a one-way organ – it absorbs nutrients from your food. Feces are nothing more than the food you couldn’t digest, along with a large addition of bacteria, which aid in digestion (and also give shit that familiar scent).

Ok that makes sense, but if it’s a one-way organ (absorption only), then how does the bilirubin get into your feces?

Besides I still want the answer to that question: in what proportions do the byproducts of your body leave by the various methods? A rough estimate would do.

22

[QUOTE]
*Originally posted by PaulT *

Any weight you lose is lost as stated above – it is breathed out, pissed out, radiated away as heat or expended as mechanical energy.

Please stop using “radiated as heat and expended as energy” as methods to remove mass. As we’ve talked about before, mass lost this way would be unmeasurable at best.

So that leaves breathed out, sweated off, and pissed away as methods to remove mass from the body. I’m just interested in knowing what proportions of each method actually take away the byproducts of metabolism.

23

My mistake, Rusalka – the alimentary canal DOES add things to your food, obviously – but it only adds things that are part of your digestive functions, like acids and bile (which is how the bilirubin gets into your feces). My point was that there’s no equipment in there for putting metabolic wastes into the stream – those are sent into the blood by your cells and excreted in gaseous or liquid form.

24

**bovary said:

"how does adenine triphosphate fit in to all this?

or does it?"**

The short answer is that it doesn’t!

ATP is the energy-providing molecule that fuels your muscles at a cellular level. You only have enough stored ATP to power yourself for a few seconds. Fortunately it is constantly re-synthesized by burning carbos, fats and/or protein via a bewildering number of reactions and routes. Which I thankfully can’t remember.

ATP is best regarded as part of the power transmission system rather than a source of energy in itself.
**Rusalka said:

“Matt I don’t think the answer is as simple as you describe. If what you are saying is true, a person who doesn’t eat won’t defecate at all after a few days. I wonder if hunger strikers stop defecating? According to your scenario, they would. I’m also interested in what proportions the mass leaves the body - your breath carries a lot of water, haven’t you ever seen glass fog up??? Also, is everything you burn just turned into water and CO2?”**

I’m a great one for over-simplifying! I don’t know about hunger-strikers, I’ll take PaulT’s word for it.

As far as proportions go, I guess it depends on what you’re doing. If you’re sitting in a cool room watching TV, I figure most of the water you produce is going into your bladder. On the other hand, marathon runners have to drink extra while they run just to stop becoming dehydrated, which implies that they are breathing/sweating out MORE water than they are producing.

Carbos can go all the way to water and CO2. If you work anaerobically you will produce lactic acid from carbos, but I think this is burned to water and CO2 later.
I think fats also go to water and CO2, but I wouldn’t stake my life on it…
Protein has some other breakdown products, ammonia for example. This is excreted as urea in urine.
**Rusalka also said:

“(I’d like to know what part of the molecule’s mass is lost, since the energy in a chemical bond doesn’t weigh anything, but that’s for another discusssion)”**

I always thought the energy in a chemical bond DOES weigh something. I had the impression E=mc2 actually meant

energy=mass

whether the energy is chemical bonds, raised weights or stretched elastic! I’m not sure where I got this idea though, so I’ll start a thread to find out if it’s true.

25

Ammonia is a gas - you actually exrete an ammonium salt dissolved in water & urea is a solid as is uric acid - they are soluble & get excreted in humans dissolved in water in sweat or urine. As do various ordinary salts, although the main one is Sodium Chloride (but the proportions of each to water depend mainly on how much you have been drinking water or alcohol… and how much salt you have been eating.)

Me picky? Who said that?