My mom made me eat pickled beets once and I think I gagged doing it so much I never had to again. I think because I was the youngest I got away with being a little more picky than my sister. We were allowed to not take food but we had to eat what we took, but I got away with picking out the celery and onions from my potato salad and macaroni salads as I didn't and still don't like crunchy stuff in that food. Maybe it helped that my mom and dad liked the celery and onions so I would pick it out and give it to them so then they had more!
Also when my dad was diagnosed with high cholesterol my mom immediately started cutting out our high fat foods, which she should have but we always had milk with our dinner and we switched right away from whole milk to skim milk, there was no using up the whole milk and a gradual shift to the skim. The day of our switch she wouldn't let us leave the table until we drank the whole glass of skim milk, it tasted so gross to us. We eventually got used to it but it was a rough switch at first.
I think it helped that my mom was a good cook so there wasn't much that we didn't want to eat although I didn't care for her scalloped potatoes with canned tuna, but I still ate it because I wanted my nightly treat.