# Excrement



## NerdyCavegirl (Apr 11, 2016)

What exactly do human waste products (1, 2, and sweat for good measure) actually contain in the way of water percentages, other fluids, and especially leftover nutrients and fuel? Are there fats, carbs, and proteins that humans excrete but other animals can use for energy? Why exactly are those things not digested and/or what do humans lack that is necessary to do so? Or a much simpler question: how many calories (not food calories) does 1 lb of human shit contain?


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## Ireth (Apr 11, 2016)

I would think that would vary somewhat based on the person's diet and overall health.


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## psychotick (Apr 11, 2016)

Hi,

For the real shit on this the wiki's useful!

Human feces - Wikipedia, the free encyclopedia

Cheers, Greg.


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## Saproxylic (Apr 11, 2016)

Really depends on who's eating it... 

 If you are a small organism that is used to feeding on bacterial biomass, feces are delicious and nutritios.


Generally humans are pretty good at digesting stuff, I would say, the fecal volume compared to the volume of food eaten, as you can see in the wiki, is pretty small. Humans could get even better at it if they acquired some form of bacterial or protozoan endosymbiont (like ruminants, for example), that would allow them to break down cellulose in plant roughage, but I can't imagine any other drastic improvements to make humans waste less nutrients through feces.

The nitrogen loss from urine is a bit more tricky, as nitrogen in living systems is pretty valuable/hard to obtain. However all animals do that (excrete nitrogenous waste). 

 I might not be the best at explaining, but one of the defining features of animal kingdom is that they are heterotrophic, which basically in this context means they are far ''better'' at breaking down complex organic compounds, than making them, so they constantly run into the problem that a large part of what they consume eventually gets broken down to small enough molecules, that they lack metabolic pathways to ''re-assamble'' into something useful again (namely ammonia, carbon dioxide and water) and they just have to get rid of that and replenish the stores of complex molecules.

In total, I would say humans aren't particularly wasteful with their resources in excreta, as long as they are healthy. Waste starts if something is not working properly (sugar in urine in case of diabetes, undigested food in case of diarrhea)


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## K.S. Crooks (Apr 17, 2016)

Also understand that feces and urine are not only things that go undigested, they also contain (especially urine) by-products from our body metabolism. For example when our body breaks down proteins the waste product is ammonia, which is highly toxic. When the ammonia in our blood pass through the liver it is converted into urea, which then is removed by a kidney and placed as part of urine. I'm sure you can look up the average percentage of water, salts and other substances in human waste, but remember it depends on what the person ate, drank, activity, body composition and weight, temperature of the environment and their personal metabolism.


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## Ben (Apr 17, 2016)

This thread is evidence that writers are insane


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## NerdyCavegirl (Apr 17, 2016)

No one is eating shit. -.- More like possibly producing less of it with a more efficient digestive system or something of the sorts.


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