When I was about 5 or 6 my mother accidentally put beets on my dinner plate. She usually didn't put food that was repulsive to me on my plate. This time she forgot. I think these were canned beets that she just plopped down on the plate without even heating. As it was a general rule that you had to "clean your plate", I asked to be excused from eating the beets. Dad chimed in and loudly ordered that "You'll finish everything on your plate". As it took me nearly an hour to finish the beets, when I started vomiting all of my dinner, Mom, Dad and Sister came running into the dinning room when they heard the commotion.
Those beets truly made me nauseous and apparently Mom told Dad, next time he forces me to "clean my plate", he will be cleaning up the vomit.
As a kid, I ate lots of food I didn't like, but my mother learned that beets and sauerkraut would actually cause me to vomit.
Still won't eat beets, and sauerkraut only in a Reuben sandwich.