I'm sure this has been discussed before so my apologies.
For the life of me I can't pick anything that sets off a flare.
I can be extremely stressed and nothing happens or life can be very smooth and I'll go into a large flare.
I can't pick any foods, although I steer clear of anything spicy, especially capsicum. Years ago I did a food elimination diet through Royal Prince Alfred Hospital in Sydney Australia and proved sensitive to Gluten and Salicilates. My theory is it might take a combination of a couple of things to set things going. Very early in the piece I was diagnosed as having coeliac disease because my enzymes 'spiked' on a blood test, however this seemed to be a blip as coeliac disease has been disproved. I try to cut down on gluten but must admit I'm have to try harder.