I've never fed my cats Purina One or Meow Mix but I just wanted to let you know that better quality cat foods that don't contain so many fillers like by products, corn, or wheat will end up costing you less and your cat will also eat and need less of it. Most vets don't know anything about nutrition so just because your vet recommends a certain food doesn't mean that you have to feed this to your cat. The expensive Veterinarny RX diets actually have some of the worst ingredients in them and they cost a lot. Here's a link to some cat foods that have been rated for their price and ingredients: http://www.petfoodratings.net/cattable.html. I've always believed that we should feed our pets the best quality diet that we can afford because good health starts from a good diet. Good luck.