I'm in the process of moving Tuffy to adult food... I've been putting about 1/4 cup of the adult food in with 3/4 cup of the puppy food.. But my problem is that he will pick out all the adult food pieces and leave his puppy food. He munches on the puppy food later in the day, but he's probably leaving a good 1/2 cup of puppy food in his bowl. I even tried mixing both foods in with some baby food but that didn't trick him, he still left the puppy food pieces in his bowl. What should I do?