I had zero problems with spicy food with my ileostomy... actually I ate the spiciest food of my life, before takedown this is the one time in your life when there's no chance of feeling it on the way out (as long as your wafer has a good seal).
Regarding the gas in soda, didn't you just post that you had an overnight leak from a ballooning pouch...? Just saying
I only ever had bad ballooning overnight from drinking seltzer at dinner, just something to think about
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Caffeine can increase motility/cause diarrhea, I limited myself to one cup with my end ileostomy and with the loop I did decaf only. You just have to test the waters slowly.
The main thing you want to be careful of with stuff like raw veggies, nuts, seeds, mushrooms, popcorn is causing a blockage. You should be able to tell if, in general, you're having mild blockage type issues or if you feel like things are flowing pretty 'smoothly'. Bloating followed by lots of output can be a sign of partial blockage for example. Six weeks is a typical amount of time to wait to see if your swelling has gone down enough that everything is flowing smoothly, but for some people it can take more or less time. Again, just test the waters and see.