I tried having a fish sandwich and fries from McDonald's a couple of times in the last year. Prior to that it had been years since I had eaten there, and the only reason I did it because I was around some younger people in college who ate there. In both instances, at least a couple of hours after I ate the McDonald's I got nauseated, and I got a migraine headache. I'm not sure how to explain this, except maybe the oil they fry the french fries in makes me feel this way? I'm a voracious omnivore who eats all kinds of food, from the mundane to the exotic, and pretty much nothing I've ever eaten made me feel that bad.