This is why partially why fiber helps with bulking and pooping. Fiber is "fiber" because it's made of things we can't digest, but our gut microbes can. One of the byproducts of their utilizing it is SCFAs, short chain fatty acids. These confer various benefits like reduced inflammation and enhanced mucous production, which helps you drop a deuce.

Feeding your microbes also means you grow more of them, which makes your turds bigger and easier for your intestines to push along.

Yet another fun fact: ruminants like cows ferment otherwise indigestible plant matter in their guts, breaking it down and growing absolutely huge quantities of microbes in the process. Then they digest those microbes. That's how they get enough protein. A cow is a mooing, shitting house of horrors if you're a microbe.

Well tough guy, this morning was an oatmeal surprise swirl, with carrots, two inches above the waterline. In a Crane Galaxy #3251D701100, you do the math.