Where does it go?

jamcdonel

This may be a little weird, but here goes.

I am currently losing about two pounds a week, (yay me!) But where does it go?

Due to the Laws of conservation of Matter and Energy, it has to go somewhere. I understand that part of it goes down the porcelain convenience, but....wow. Am I really pooping out 2 pounds more than I eat on a weekly basis?

I took biochemistry (shudder) and physiology way back in the day, but somehow they never got around to this bit.

Things that make you go hmmmmm.

kgirlhart

There was a thread recently about this called "A couple of things about weight loss". I'm not sure how to link it. It was really interesting and answers this question. If you search the title you should find it.

SezxyStef

I remember watching a tedtalk on this...and if I remember correctly we literally breath it out...

Tubbs216

Oh there's a great video which explains it really well, which hopefully someone will post. Yes, some goes down the loo in both forms, but a lot gets excreted in breath, which surprised me.

CJsf1t

Most of it goes out as CO2 and water. That is , through breathing, pee, and some sweating too.

SueInAz

SezxyStef wrote: »

I remember watching a tedtalk on this...and if I remember correctly we literally breath it out...

Yes. We breathe out a lot of water but it also gets expended as heat. There's a reason why we call it "burning calories". Calories are a measure of heat, specifically 1 calorie is the energy needed to raise the temperature of 1 gram of water through 1 °C (now usually defined as 4.1868 joules).

Jruzer

You mostly breathe it out. Some is lost in sweat, urine, and feces, but most of the fat is converted to CO2.

Aside:
I get amused because sometimes you'll hear people say, "It's converted to energy, you know like E=mc^2?" Heh. If we had to do it this way (which we don't!) you'd have to burn close to 10 TRILLION kcal to lose a pound.

jamcdonel

I just found an article about breathing it out as CO2. That makes sense as some of the byproducts of the Krebs Cycle are water and CO2... interesting.

Here's to more peeing and heavy breathing for everyone!

jamcdonel

(I think I just triggered myself talking biochemistry like that)

Aaron_K123

Your food and body is basically composed of hydrocarbons with some nitrogen in the protein and not much else. Most of the weight lost comes from carbon which you breath out. Breath in O2, breath out CO2. Majority of your weight is lost from that carbon. Oxygen hydrogen are combined into water and are lost from whatever way you lose water (crying, sweat, urine) and nitrogen is lost in urine in the form of uric acid.

In terms of going number 2 that stuff was never really digested and never really a part of you.

Aaron_K123

SueInAz wrote: »

SezxyStef wrote: »

I remember watching a tedtalk on this...and if I remember correctly we literally breath it out...

Yes. We breathe out a lot of water but it also gets expended as heat. There's a reason why we call it "burning calories". Calories are a measure of heat, specifically 1 calorie is the energy needed to raise the temperature of 1 gram of water through 1 °C (now usually defined as 4.1868 joules).

None of our mass is converted into heat...that would be a nuclear reaction. So although I get what you are saying it's technically wrong as it is not an explanation for weight. The energy is contained within chemical bonds and mass is conserved in release of that energy via oxidation and hydrolysis. No mass is converted to heat.

Fursian

I was also surprised to hear that we breathe it out. Then I started to think about gyms and the funny, but slightly horrific, thought that you'd be breathing in everyone's fat. Then the visions of a buff person walking into a gym, and waddling back out after their session

JessicaB523

Here's the TedTalk... https://www.youtube.com/watch?v=vuIlsN32WaE