My 2 17 week old kittens throw up daily, usually after eating?

i got the pair from a shelter and they have been fixed and all shots and wormed, i also got them declawed 3 weeks ago...ever since i got them they usually throw up on a daily basis. they were at the vet 3 weeks ago for a full checkup before the declaw and are in good health. a friend of mine said sometimes kittens will eat fast and too much causing them to throw up...anybody got any other suggestions? they are happy and playfull and do not seem sick otherwise.