Doggie dillemmas, please help?

I have 3 cats and a dog. My problem lies therein, when I leave the house for work, and my dog decides to help herself to the cat's food dishes. I would love to put the dishes at a level that she cannot reach...but that would also make it so that the cats couldn't reach them either. Is there any kind of training that I could do with her, that would reinforce her not eating the cat's food while i'm away? Also, she knows not to do it when i'm home, which makes this task 2 times as frustrating.