my son

from a psychological approach, i would make something for yourself that he wouldn't usually want, and really emphasise how nice it is (oooooohhh mmm yum yum) haha, usually the jealous child will at least try what you're having if it seems like they can't/shouldn't. another idea, though he might be a bit young for it is to associate food with someone he admires, dennis the menace pasta for example :) good luck, hope he grows up big and strong :D

It's a no simple thing, maybe you cand do him the chips only if he eats something before.