I don't have any food allergies that I know of. I AM, however, a very picky eater.
One of my friends is allergic to the dye Red #40. She found this out a few years ago, after having a severe reaction to something with that in it. So she has to be really, really careful when she gets foods, medications, etc....even if there's just a trace of the dye in it, she can't have it.