Good post. i have suffered from i.b.s. most of my life and recently was diagnosed with diverticulosis.
I was told to change my diet to low FODMAP , gluten free, wheat free and dairy free.

Since the diet my i.b.s. is nearly non-existent :-)
Not gone vegan or vegetarien yet but if anyone suffers from i.b.s. or stomache problems try low FODMAP. it only took 3 days for my symptoms to improve.

Low fodmap foods....
https://www.ibsdiets.org/fodmap-diet/fodmap-food-list/