Grab some granola bars from the snack counter, bring them into the stall, drop them into the toilet so your coworkers won't think anything's amiss

I mean I can only speak for myself, but I don't look at another man going into a bathroom and stall and think "wait a minute.... is he NOT taking a shit?" then start getting my stopwatch out and cross-referencing that with studies of average defecation times.

Surely no one really cares.

There is a 100% chance that nobody will notice or care.