Cats are essentially carnivorous and for many years they have fed themselves with their own hunting (birds, rodents, fish, etc.). Nowadays there is a lot of balanced food that may replace that diet and it may even improve it, but we have to choose the one with the best quality regarding production and proteins and one that has the enough additives to protect urinary tract, since some commercial food may cause or help to the formation of urinary calculi. (See note about urinary difficulty.)