Food doesn't really cause the problems in Crohn's, but food certainly can exacerbate any existing issues. If you have a stricture, certain foods can cause a blockage, and if you have existing inflammation, certain foods can cause it to feel worse.
I don't think food causes Crohn's per se. However, I know there are some food additives that do cause inflammation for me. One in particular is Carrageenan. I have talked with others who are sensitive to carrageenan, however I know other Crohn's patients who have no problem eating this additive.