I wouldn't be too precious about these things. My sister started working cabin crew and refused at the beginning to do a poop on the plane. Around that time she started low carbing and didn't drink enough water. Well, surprise, surprise, she got constipated....to the point that her bf had to take her to the emergency room at the hospital.
Of course, that can hppen any time that your eatin ghabits changed, in 1998 I took a cycle tour in Poland. They eat a lot root vegetables. The days went by and then I noticed, I haven't pooped in a few days, that's a really painful situation that you can put yourself in.......