D.H.
I definitely wouldn't be hitting the child. (It's interesting the difference between pediatricians. Another person told us that her pediatrician said that the child is exploring and to let them, which they are, but you can still nip that a bit.) Hitting is never an option. That only redirects their attention to you hitting and not the problem at hand and teaches him to eventually become experts at hitting.
We were just discussing this on a Love and Logic group that I'm on. Someone has triplets and this is what she did with this meal battle. First of all, it would really help to get the book called "How to Get your Kid to Eat, but not too much" by Ellyn Satter. She said that it is a wonderful, wonderful book about teaching your kids healthy attitudes about eating and food and how to avoid food and meal battles. The mother said that within one day, meals were SO much better.
Here are some things you can do though (read further below to see what to do when he throws again):
First have all the food cut on and on the trays BEFORE he is in his chair because some kids will quickly lose patience for sitting there.
Only put 1 tbsp of each item on the tray at a time. - If there is so much food on the tray, the child can easily be dumping it on the floor. This will also allow him to learn to ask for more and evaluate his level of hunger.
Do not react about food. This means no pressuring to eat, praising for eating something, pushing them to eat more, tricking. It's ok to comment, "I see you like peas today," or praise the skills they are using. This is mentioned in the book above. It keeps eating from becoming a battle or control issue.
If he starts fussing and doesn't want anything, immediately get him down. He is done...whether he ate one bite or not. Parents tend to keep their kids in the highchair way too long. He'll eat what he needs. In that book, it talks about how little they have to eat to meet their nutritional requirements (2 tbsp of veggies is the daily min req.). Everything else is a bonus.
Let's say he resists going in the chair...just say, "Ok, we can eat a little later." Let him decide when he is hungry. This is an important skill. We don't let others decide when we are hungry at home, do we? I certainly don't.
If he throws a cup, in a light tone say, "Uh-oh. Cup is all gone." Then put it on the table next to you. When he gestures or asks for it, just say, "Oh, this is sad. Cup is all gone." No lectures. Lecturing throws the lesson out of the window.
If he drops food (even if it's the very first bite), very brightly say, "All done! Breakfast is over!" and down he goes. If he barely ate, try again in an hour or 15 or 30 minutes, or for an older child, the next snack. As he gets used to this routine and what you'll do...give it a daily dose of a week or two (he'll pick up on it), then he'll know that throwing food is an immediate uh-oh, but he'll get to try again immediately after he is done in time out. It shouldn't happen often after that. When it does, you just tell him, "If you don't want it, you don't have to eat it, but we don't throw food. It's bad manners." (No yelling. Just empathy.)
If you are still eating your dinner when he wants down, let him down, but continue to finish your dinner. Another matter, if he is trying to eat off your plate, put him back in the chair and say, "I'll be glad to give you some _______ when you are sitting in your chair." If he resists, say, "Ok, you're welcome to get down." and put him down. Repeat a few times and he will either stay in his chair or stop begging off of you.
The mother of the triplets said that the Satter book up above was wonderful. She said that changing what she was doing solved most of the problem. And with parenting, we all know that what *we* do is either going to fuel the fire or stop the problem all together.
I hope this helps!