....since he wasn't eating at all and would turn his nose up and walk away. He's been on 6-8+ types of foods. Now he's on Royal Cainine. Anyways, I did it slowly when I did switch. I put in 25% (or less) of the new and 75% (or more) of the old. It took 3-4 weeks before he would be totally switched, if we even got that far. He picked out the new and left the old. But the boy finally likes the Royal Cainine which is for picky eaters I am told.