I've replied to quite a few people and I'm going to bed now.
I'll edit the posts with updates when my poopless journey ends. Either when the three-day poopless period is over (28th June) or when the whole thing is over (30 June/1 July).
Okay I'll give in a tiny bit only because this barely narrows it down: one of them is ridiculously close to what is actually the case. Like, I'm actually doing the thing you mentioned in the point, just your reasoning is wrong.
P.S.: The actual reasoning is borderline impossible for anyone to guess so just stop trying guys.
This is kind of a group thing and I'm the only one not allowed to poop for personal reasons. They'll be expecting me to eat food that's at least somewhat normal.
I haven't eaten fibre for a while to prepare for this. I don't mind severe constipation but i just need to get through those 3 days without pooping. Also not going on a hike idk why everyone is assuming that. Anyways, thanks.