when we first got Tyke he was 12 weeks old in Sept. he wouldn't eat anything i offered him. so the first few days he wasn't doing good. had to give him the karo syrup in a sryinge to get his sugar up. well i had to call the place we got him and find out what food they were feeding him. well it was Diamond Puppy food. called around and found where they sold it and went and bought some. he started eating. i guess he only likes that food. since he's older now i thought i'd try to switch him to a better brand of food. sent off and got samples of chicken soup, wellness, and Canadia. he won't eat any of them. he wants only his Diamond puppy food. what i'm trying to say is maybe you shouldn't be trying to change the food over just yet. Tyke is almost 6 monthes old and still loves his puppy food. don't know how i'm going to switch him to adult food when the time comes. hope this helps some.