system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] How often would the Flash need to take a dump?

I mean, we see scenes of him eating a lot to gain energy. His body quickly converts the food into energy, so naturally he'd need to relieve it, right? Do they ever even mention this in canon?
gpt
Waste processes are only very, very rarely ever brought up for any characters in comics. The Flash is not really any different in that regard.

On the other hand, once the Speed Force concept was introduced, speedsters needing lots of food was basically handwaved away and ignored.

Also, most of the time your waste isn't actually mostly undigested food - it's mostly old cells, with only material that you can't actually digest being mixed in.