I'd never advocate anyone doing it this way, but fwiw...
DW was a picky eater who began spending the summers at an uncle's house as a child. She was served whatever was prepared for that meal. If she didn't eat it, it went in the fridge. When she was hungry, that meal came out of the fridge. At the next mealtime, everyone else was served fresh food, and she was served her previous leftovers. If she refused to eat it, it went back in the fridge. Wash, rinse, repeat. Needless to say, the offering became less appetizing every time.
There was no negotiating, and no sympathy. When she became upset, there was a rock outside she could sit on until she was done crying. She spent a lot of time on that rock.
As horrible as the experience was, she credits him for turning the behavior around, and she's thankful for it today. She's a major foodie and attended culinary school.
