It's heartbreaking when your feline pal has kidney problems. There's not a whole lot you can do to help him feel better. But what you can do is simple: Feed a prescription diet recommended by your vet, and encourage your cat to drink plenty of water.
Sadly, a prescription diet won't reverse or cure your cat's kidney disease. The good news, though, is that the right diet can slow the disease down by reducing the load on the kidneys. If your cat's kidneys don't have to work so hard processing the protein and other components of the food, they can keep doing their job longer. This helps your kitty feel better and can also extend his life.
Most prescription kidney diets for your cat are low in protein; the protein they do contain is high-quality, such as from eggs and meat instead of from grains. There is some controversy over whether a low-protein diet actually helps reduce the amount of work for the kidneys. Cats must have some protein in their diet to stay healthy, so veterinary prescription dieticians try to find a balance between providing enough protein without making the kidneys work too hard.
Even more important than reduced protein levels in prescription kidney diets is a low amount of phosphorus. It takes a lot of work for your cat's kidneys to process phosphorous, so even if you decide not to use a prescription diet, look for food that's low in phosphorous.
Wet vs. Dry
When your cat has kidney disease, he needs extra fluids. Some cats stop drinking as much they should when they don't feel well, making it harder to keep things flowing through his kidneys. Wet prescription food can help add some of the fluids your cat needs. Feeding strictly wet food can be bad for his teeth, however; and some cats will get finicky and refuse to eat dry food again after they get a taste of canned food. Mixing wet and dry food together can help keep your kitty's teeth in shape while still giving him the water he needs.
The worst thing about prescription kidney diets isn't that they're expensive; it's that most cats just don't like them. When your cat is already sick, it can be hard to get him to eat something new. Mix the new prescription diet in with your cat's regular food to start. If he still won't eat it, don't let him starve. Ask your vet for a different brand of prescription food or an appetite stimulant.
Treats and Additions
Be careful about adding extras to your cat's prescription kidney diet. Giving him a little something extra to make up for his food being less tasty could defeat the whole purpose of the diet. Mixing soup broth, meat or other "people foods" in with his food to get him to eat is a bad idea -- it could make more work for his kidneys.