I was a fussy eater as a child, (and so was dsis) - no idea why. When I went to school, the food was so disgusting, that I got even fussier.
I owuld not eat eggs in any form, the only veg I would eat was peas & carrots, would only eat one type of sausage, etc.
My Mum used to have to pre-warn people we were visiting that we would only eat fishfingers, so not to bother concocting some gourmet delicacy.
The one thing I can remember is that basically we ate waht we wanted to..within reason. What's the point of serving up a whole meal to children when you know they won;t eat any of it?
We were encouraged to try new things all teh time, and I can remember a breakthrough when I discovered salad cream at about 7 and started eating salad!
The thing is, as an adult I will eat pretty much anything, and my adult tastes developed between the ages of about 8 and 14.
So imo making a big fuss about food is just not worth the trouble.
As long as DS eats a balanced diet from the various food groups, even IF he only eats carrots, peas and olives, I make sure he always ahs them, and regulalry serve otehr veg and put it on his plate. If he doesn;t like it (he always tried stuff) he is allowed to leave it, no questions.
I do also insist a reasonable effort has been made with his first course before any pudding is allowed, but he doesn;t have to finish it completely.
I think he eats well, but he has always eaten good quantities, so never been in the situation where he would refuse to eat at all, which I think must be incredibly stressful, and possibly lead to difficulties at mealtimes.