PMI is ok, but I have seen Hill's Prescription diet save alot more lives. I have helped a 90lb labrador get through a GI illness for a good month on only a/d and fluids. He lost a bit of weight, but was still his happy self.

Oh, and I've seen quite a few cats get urinary stones from PMI... so!

And if you are truly not feeding your cat any meat, good lord.. Cats are CARNIVORES. You CANNOT force your beliefs onto an animal that IS UNABLE to process grains, vegetables, fruits, whatever. All you are going to give them are heart problems, organ failure and a premature death. Think of the animals instead of yourself. Dogs are also more carnivore than omnivore, and too many grains can make them gassy and more prone to disease. I for one, do not like Ol' Roy farts(which is just cardboard, sawdust and meat flavoring).