LOL! I've done that! But be careful, they WILL figure it out! What I do is put a few of the treats in with their new food. Invariably they will get some of the new food in their mouths. Of course if your cats are as intelligent as mine, they will also figure that out and just pick out the treats. I had to keep trying different foods until I hit upon ones they liked. Luckily I had received some free samples of the Royal Canin at a cat show and they gobbled it up, so that's what Mitzi is on now - the light formula. Good luck!