I once ate something on UA that made me sick. No, I didn't drink too much. It was OAK/DEN/IAH (with a quick connection) - shortly after DEN takeoff, I went to the lav and ... well, I was glad I was sitting up front. I also told the FA - a few mins "after", I felt decent. I had apparently turned very pale white. I was fine in a short time. That said, I didn't eat any more UA food that day.....