This sounds basic, but think beyond the surface here. This isn’t just a crappy question.
Of course it comes from after you digest the food you eat, but if you’re pooping out masses, then how are you absorbing the calories? For example if you absorb close to 100% or 90% of what you eat, then why do we need to poop so much?
Are not absorbing nearly as much as we think we are?
People often say, “it comes from the indigestible parts of what you eat.” If that’s the case, then that is a large amount of stuff we don’t absorb. People also like to say, “you need fiber to bulk up your stools.”
That doesn’t make sense either. I can’t speak for everyone, but from personal anecdotes I noticed that bulky logs can occur even if the food as no fiber in it.
Fiber is supposed to be the indegistble part of food, that is mainly made of complex vegetable carbohydrates. So why do we need fiber if a large portion of non-fibrous foods also has bulks of non digestible mass?
You’re mostly correct … the digestive system isn’t especially efficient so sure part of the “indigestibles” wouldn’t be exactly indigestible first time through … just the intestines didn’t quite get to them … and food has a lot of water and that does generally all get absorbed … comes out as #1 …
Of the solid portion, 1/3 to 1/2 of that is bacteria. The remainder is mostly a mix of insoluble fiber (which helps to keep enough water in the intestine to move things along, and also binds bile salts and keeps them from being reabsorbed) along with soluble fiber and other unabsorbed food.
Digestion is not that efficient a process. There’s lots of unabsorbed calories in stool. That’s why there’s a niche for coprophages, or animals which feed on the stool of other creatures (such as ‘bottom feeders’) and indeed, some animals feed on their own stool (rabbits).
Bile salts are composed of broken down red blood cells; they’re a rather small part of what’s in stool. They do give the characteristic brown color, though.
About a decade ago, some group made cookies out of poop…and a quick Google search notes another breakthrough (ew) where a Japanese group made “steak” out of poo.
didn’t I just read the other day on here somewhere about a dairy farmer who got rich making flower pots out of his herd’s poop? The kind you put in the ground with the plant still in them, which then decomposes and feeds the plant.
Here’s Cecil on “why is shit brown?”… but I remember the writer asking the question called himself “Billy Rubin” (get it?). Either this isn’t quite the right column, or something got changed in its transfer to the Interwebs (besides the euphemizing of “shit”).
(“Bilirubin” is the technical name for the “broken down red blood cells” that Quadgop and GaryM mentioned upthread).
In Thailand, I’ve bought cards and other paper products made from elephant poop. Not common to find though. I bought them at a table set up at one of the elephant-polo tournaments. It’s very rough, not something I’d normally use. Sent them all to friends in the US.