# What goes in must come out? \[A question about poo\] **URL:** \ **Category:** Factual Questions\ **Created:** [April 12, 2019, 5:19pm UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447 "2019-04-12T17:19:12Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [April 13, 2019, 2:30am UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447/21 "2019-04-13T02:30:21Z")
> [@Dr.Strangelove](#): > > Is it just energy+hydrogen … . Yes.This picture explains it better : [http://www.pinetum.org/Lovett/psyn-3.gif](http://www.pinetum.org/Lovett/psyn-3.gif) ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [April 13, 2019, 3:13am UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447/22 "2019-04-13T03:13:36Z")
For a thread about people and their poop, this thread took a hard left turn pretty quickly. An incredibly informative turn, to be sure. I’m just amused by the topic shift & speed. 🙂 ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [April 13, 2019, 7:11am UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447/23 "2019-04-13T07:11:27Z")
> [@Walken\_After\_Midnight](#): > > There must be also be some variable quantity of food that is expelled as fart. Yes, but it’s pretty trivial. It’s a fairly small amount of matter unless you’re outgassing from your nether orifice at close to the rate you exhale. That’s very unlikely. > [@](#): > > What do we do with the oxygen once we’ve used it? Does it all go back out of the mouth as carbon dioxide? More or less. When carbohydrates (i.e. glucose) are burned, the carbon and hydrogen in that molecule combine with oxygen to form carbon dioxide and water. The dioxide gets breathed out and the water (if it’s excess) gets pissed out. But note that not all the oxygen in that reaction is from the air; a third of it is already in the sugar molecule. The reaction looks like this: C[sub]6[/sub]H[sub]12[/sub]O[sub]6[/sub] + 6O[sub]2[/sub] –\> 6CO[sub]2[/sub] + 6H[sub]2[/sub]O + energy ---
**Author:** ![Nava](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@Nava](https://boards.straightdope.com/u/Nava)\ **Post date:** [April 13, 2019, 8:19am UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447/24 "2019-04-13T08:19:34Z")
> [@senoy](#): > > You breathe it and pee it out. And some of it stays inside, as part of you. Depending on your age, your diet and your habits, it will show as growth or as girth. There are also substances which can be absorbed but can’t be eliminated, such as some poisonous heavy metals (lead, arsenic). > [@Beckdawrek](#): > > So, fat persons are just full of shit? That just seems rude. No, but whether thin or fat, we’re all literally full of ourselves 🙂 ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [April 13, 2019, 2:20pm UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447/25 "2019-04-13T14:20:56Z")
> [@am77494](#): > > Please give it another read and check if this correct. I did read it again but maybe I am not reading it correctly. :smack: I had some chemistry backward in my head and missed a “not” in your quote. I even skimmed the start of the paper! Mea culpa. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 13, 2019, 3:36pm UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447/26 "2019-04-13T15:36:59Z")
And as the starter of that digression, color me educated. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [April 13, 2019, 4:01pm UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447/27 "2019-04-13T16:01:45Z")
I would just like to point out that “poo” and “pooing” are obnoxiously pseudo-cute names, and the proper medical term for excretion is “taking a large, steaming dump”\*. \*which is what my spaniel managed not just once, but twice during his memorable vet clinic visit on Friday. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 15, 2019, 11:59am UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447/28 "2019-04-15T11:59:19Z")
The Damn Interesting website recently posted this interesting and relevant article: > **['Every Breath You Take' is the ultimate all-round song (according to science)](https://www.damninteresting.com/shared/every-breath-you-take-is-the-ultimate-all-round-song-according-to-science/)** > > Researcher analyzed streaming data for nearly 4 million songs on Spotify to see if there was a pattern to the types of music we listen to. They came up with five different blocks of music. It describes the case of a morbidly obese man who basically fasted for over a year: > [@Damn Interesting](#): > > Barbieri’s doctors prescribed a novel diet of non-caloric fluids, yeast, electrolytes, and vitamin/mineral supplements. His bowel movements were few and far between: > [@Damn Interesting](#): > > The doctors did not take stool samples during this time, but records indicated that the patient’s bowel movements became quite infrequent, with an average of 42 days between evacuations. During his remarkable fast, he lost 276 pounds, despite not producing 276 pounds of feces: > [@Damn Interesting](#): > > The law of conservation of mass observes that matter cannot be created or destroyed, so it follows that a human must expel matter from their body in order to lose weight. A survey in 2013 asked health professionals how they believe the body rids itself of metabolized fat, and most respondents incorrectly surmised that “burned” fat is converted to energy or heat. Many others—also incorrectly—believed that most of the metabolites are converted into muscle, or excreted as feces. In fact, contrary to intuition, over 90% of lost weight leaves the body as carbon dioxide exhaled from the lungs, disappearing into thin air. The remainder is excreted in urine, sweat, and other bodily fluids. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [April 15, 2019, 12:43pm UTC](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447/29 "2019-04-15T12:43:22Z")
> [@](#): > > Originally Posted by Damn Interesting The law of conservation of mass observes that matter cannot be created or destroyed, so it follows that a human must expel matter from their body in order to lose weight. A survey in 2013 asked health professionals how they believe the body rids itself of metabolized fat, and most respondents incorrectly surmised that “burned” fat is converted to energy or heat. Many others—also incorrectly—believed that most of the metabolites are converted into muscle, or excreted as feces. In fact, contrary to intuition, over 90% of lost weight leaves the body as carbon dioxide exhaled from the lungs, disappearing into thin air. The remainder is excreted in urine, sweat, and other bodily fluids. Winston Churchill: “We have nothing to give but urine, sweat, and other bodily fluids. Oh, and carbon dioxide. Lots and lots of carbon dioxide.” [Previous page](https://boards.straightdope.com/t/what-goes-in-must-come-out-a-question-about-poo/832447.md?page=1)