I think just the food change, but it could be permanent. We switched our cats food twice in the last 6 months or so to combat knock-out quality stench. I think they eat a Eukanuba naturals or something now....too lazy to get up This has the least smelly poo that we have found, and it is a decent price, so I think we are going to stick with it.

However...one of our cats wont eat it...she prefers the dog food...and of course the dogs like the cat food.