I absolutely love spicy food, and it’s never affected my gut. I was actually confused when I read about people getting the shits after a curry and wondered if it was a joke. I’ve had curries so hot it caused people to recoil into a coughing and sweating fit after they dipped their finger in and had a taste and I have one every other day. I feel the burning in my mouth, my face turns red, my forehead sweats, my esophagus feels weird, but (tmi I know lol) when I go to the toilet I’m completely fine. no gut pains either.
I used to live in New Mexico for a while and there was a common joke: how do you tell if someone is a native New Mexican? They keep a fire extinguisher in the bathroom.
It’s not so much that you taste it on the way out, it’s that there’s undigested capsaicin that burns, uh, other mucus membranes on the way out. Fortunately not something that bothers me much either, but I get hints of it sometimes when my niece makes what I call her nuclear fire curry.