Why is my cat vomiting?

I have a 4 year old Havana Brown, and he has recently started vomiting his food. Right after he eats he will just puke it up, then start eating the undigested food. Is this normal, or a breed thing? I don't know if he is eating too fast, or what. I feed him between a quarter and a half cup of food in the morning and that lasts usually all day. He drinks water from the tub faucet that I keep dripping, so I know that he is well hydrated, and he poops fine, too. Any suggestions are appreciated!!