J.C.
I actually answered this question about a year ago. Here's what I said then and still agree with now:
I definitely know how frustrating throwing food can be, but hang in there. My son went through the tip the plate, throw the food, toss the cup phase as well. It was not fun. Every time he would drop something or go to drop something I would react. Either by saying, "Put your hand down." or "Don't throw that food."...you get the picture. It never worked. So, I turned to my mom for help. She simply said, "Stop reacting." Toddlers love a good reaction from mom and dad. It gives them a little power and also becomes somewhat of a game. My mom told me that the second we saw that he was going to throw food we should immediately take his plate and cup away and say, "We don't throw our food. Food is for eating." I then was to wait a couple of minutes and then place a piece of food in front of him and offer him a sip from his cup and explain that until he could sit at the table like a big boy he would not be getting his plate and cup back. We tried it. He dropped his food. We did not react at all. We did not bend down to pick up the food on the floor. We simply took his plate and cup, let him deal with that for a minute and then gave him a piece of food. Yes, meal times were longer because of this one piece of food at a time strategy, but after doing this for about a week we are now the proud parents of a non-food thrower. Well, 98% of the time at least. :) Good luck and remember don't pick up that food right away.