Plenty of authors include things like their characters eating or relieving themselves or any of a hundred other little details we usually do without considering it important.

If, however, you make a point of stressing the moment in your writing, you are telling your readers that it is important, or you're attempting to make it humorous, etc. If your goal is to be humorous, fine, not a problem. But if you just feel like regular things should be in the text, include them, and don't worry.

A lot of authors don't include mundane things because it's essentially a waste of text. Unless you're trying to juxtapose a guy's pre-adventure life by showing him mowing the lawn, cleaning between his toes, etc, there's no reason to show it. All the readers should assume it happens unless the author makes a point of saying it doesn't in the text. If a writer were to truly try to write every little thing that a character does, than it would take us much, much longer to read about the characters, and we would quickly bore of descriptions of brushing teeth, toilet paper usage and folding clothing long before we ever encounter monsters or magic.

It's like in science fiction tv where there were jokes about no one in Star Trek using the bathroom. There was even a marathon special where Johnathan Frakes showed a schematic of the ship and where the bathrooms are, tongue in cheek, of course. There was never a moment when the writers of Star Trek thought showing Picard straining over the porcelain goddess would add to the show, so it didn't happen. Some readers/viewers might desperately want to see more evidence that the characters are human so they can identify with it, but most of us really don't think about it. That said, when Joss Whedon made a point of showing his Firefly characters had toilets in their quarters, it made sense, but was largely not an important issue. Whedon, though, did want to show that that ship was a home to them, a place just like our house, and their activities when not working were important for that feeling.

I think it was Vonnegut that listed rules for writing and included "Never write more than you have to" or some such. In other words, if it's not going to advance the story or provide foreshadowing, you're wasting the reader's time when you write it. As much as it defined his style, would any of us really have gotten less out of Robert Jordan's Wheel of Time books if he'd spent a few less words describing dresses?

Also on a more specific note, I personally hate scatalogical humor and inclusions and find it pointlessly crude and childish. Just because we all do it, it doesn't mean it's anything most of us wish to discuss. Maybe if it smelled better. *shrug*