Grains are a big one for me. Red/fatty meat also seems to be one as well. I will say it’s been difficult to pinpoint exact triggers and far easier to pinpoint things that don’t trigger me though.

I know rice/chicken are two things that I tolerate well. Dairy seems to be fairly well tolerated too. Bland crackers like saltines and even Nilla wafers are usually fine as well.

Oddly, one thing that really triggers me is things that are fruit snacks/similar items. Not sure if it is gelatin or what, but something in them sets me off.