Have you tried getting him to apologize for saying "yucky?" To you and also to the others at the table. That is a consequence for being rude. And, I don't think you have much to worry about, long term. If the other kids like eating, they won't stop eating because this child doesn't. It might make them eat less of the things they aren't super keen on, but if they really like yogurt with fruit, or toast with jam, they aren't going to go hungry, IMO.