....and then one day you stuff your face with gluten and vegetable oils and all that nasty junk. Even though before eating the stuff never caused any reaction (but you avoided it for years because it's crap), is it possible to have built up an intolerance to it? Will your body freak the heck out now that you've reintroduced these long-avoided foods?

I've heard that some vegetarians adapt so much that eating meat really messes them up. I'm wondering if something similar could be going on with gluten, wheat, etc.

(Apologies if this has been covered before, I couldn't find anything.)