I was a very picky eater as a kid (and still now as an adult). I probably would have starved myself to an unhealthy level had I been forced to eat what was made without my input. I have major food issues still because of the methods used on me, how they didn’t work with my personality and tastes.
So when my kid refused to eat, I worked with it. By 4, my kid could help me cook some things. The urge to try new things increases if the kid helps shop for it, prep it, cook it, plate it. As language improves, kids can say “I like peanut butter, not peanut butter and jelly”. They have the vocabulary and the ability to get specific. I’m sure some 2-year olds can do that, but it’s harder for some kids. Hell, even now as an adult I can’t tell you why I like tomato sauce but won’t eat tomatoes.
My kid also had some physical issues. Whether they were caused by the not-eating or a symptom of it, I’ll never know. Mine just plain old wouldn’t eat, so it’s a little different from being picky, but when there was eating, it was picky eating.
It’s very, very different now. I get asked “Can I try this?” We haven’t added much new to the diet, but at least everything I make gets TRIED.
I read a book once that just said not to stress out over every meal and it changed my whole outlook. I used to cry because there was like 200 calories being consumed in a meal, ribs showing through clothes. Every skipped meal was a nightmare. But I just did my best and when he grew up, a lot of it passed. I couldn’t change the diet, but I could change how I perceived it. And when we have regular-kid pickyness now? It’s not that hard to cook some frozen chicken nuggets or pull out a lunchables or make a PB&J. It’s better for ME to make something different for us both and let it go than to force feed a kid.
There is no magical answer, as every kid is different and doesn’t eat for myriad reasons. Just don’t sweat it, see a doctor if it affects growth. Involve him in the process.
Plus when mine went to school? A HUGE change. Part of it was being so hungry from all the activity, but it was also due to seeing what all the other kids did every day.