Ask Einstein: I’m a Cat with Kidney Disease; What Can I Eat?



I’m an old cat; I mean really old — 24, to be exact. When I was a youngster of 20, my equally elderly owner went into a nursing home and I found myself on death row. Fortunately, a nice lady fell in love with me and took me home with her.

Although I’m long-of-fang, I can still jump up on the furniture and climb my cat tree. That doesn’t mean I have the body of a 20-month-old. I have arthritis, some of my teeth have gone AWOL, and I’m skinny as a supermodel ’cause my vet says I have chronic renal failure.

I just don’t want to eat much anymore. Any suggestions on yummy high-calorie treats that are safe for a kidney kitty?

Starving Spike

Yo, Spike,

Remember I’m not a vet, but I watch Animal Planet. You and your human might want to attack your waning waistline on several fronts.

Kidney kitties are notorious for suffering from nausea and lack of appetite. But the possible causes are legion. Dehydration, high phosphorus levels, metabolic acidosis, fluid retention, and constipation may make you want to puke up an intestine.

Other non-kidney-related issues could also make you ignore your food bowl: pain, dental disease, antibiotics, and pancreatitis. Your mom might want to have your vet check you out. If he can address the reason for your lack of appetite, hopefully you’ll pack on some weight. She can ask your vet about some prescription appetite stimulants like cyproheptidine or Mirtazipine and anti-nausea meds or antacids.

If you’re suffering from dehydration, subcutaneous fluids may temporarily relieve the pukes and increase your appetite. Your vet can show your human how to do this at home. Probiotics can also help settle the belly, especially if you’re taking antibiotics. My assistant has seen an improvement in her renal cats by giving the supplement red deer antler velvet.

Board-certified veterinary nutritionist Tony Buffington isn’t a fan of treats. The professor in the Department of Veterinary Clinical Sciences at Ohio State University says there are a few veterinary treats that are low in phosphorus and sodium, but they’re not high in calories. Ask your vet about Royal Canin Veterinary Diet Feline Cat Treats and Vetri-Science Renal Essentials Feline Bite-Sized Cat Chews.

Dr. B. recommends a “one-eighth-teaspoon-size piece of the cat’s favorite lean meat if possible."

My buddy Dr. Drew Weigner, an exclusively feline veterinarian in Atlanta, says, "As far as homemade treats, anything low in protein and sodium should be fine in moderation, but that excludes most things cats like! Low-sodium chicken broth and tuna juice would be fine, as are most vegetables, if they like them. Fortunately, quite a number of cats like cantaloupe, of all things, and that’s a great treat for cats with kidney disease."

Jumpstarting the appetite

Some kitties can be coaxed to eat. Your server should offer small meals throughout the day rather than one big meal. You might like dinner conversation. Your human can sit with you at mealtime and talk to you, stroke you, encourage you to take one more bite or even hand-feed you. She might even put a dab of food on your paw. If you feel well enough to groom, you’ll ingest a little nutrition.

So since safe treats won’t help you pack on the pounds, your human needs to make your food more exciting.

Cat food

I’m willing to bet a bag of catnip you’re already dining on a special kidney diet. That’s good. Unfortunately there’s no cure for CRF, but a diet low in sodium and phosphorus may slow down the loss of kidney function.

While the other kitties in the house may think your kidney cuisine is positively delectable, you turn your nose up at it. There are many kidney diets, not just the brand your vet carries. Your mom might want to try different brands to see if another food appeals to you. If you don’t like the kibble, then check out the canned version.

Your mom needs to understand that a cat (especially a sick cat) can’t be bullied into eating a certain kind of food. Kitties are perfectly capable of starving ourselves to death if the food doesn’t appeal to us. So it’s important that you eat something, anything, until Mom can slowly switch you to a kidney-friendly food.

"If they’re not eating, the best thing to feed them is anything they’ll eat," Dr. Weigner tells me. "Most of these cats are forced to eat renal diets, which are low in protein (of course). But cats are carnivores, and protein is what makes their diet palatable. So now they’re sick and not eating well, and made to eat a diet that you don’t particularly like. So it’s best to just keep kitties eating until they respond to treatment, and wait until they’re feeling better before changing their diet."

Perhaps she can mix your kidney food with your favorite canned food. Adding condiments to your meal may help rev up your appetite.

Here are a few things your mom can try to make that kidney diet more palatable:

  • Don’t serve cold food. Cats instinctively prefer food that’s the body temperature of a mouse. Warm it on defrost until it’s warm to the touch.
  • Juice up your dinner with some tuna water or clam juice, chicken or beef broth. Mom needs to check the label to make sure it’s safe for you to eat. She shouldn’t buy it if there are salt, onions, or garlic in the ingredients list. Don’t confuse consomm├® with broth. Consomm├® contains too much sodium. Your mom can always boil a chicken for broth and share a treat of meat with you (if your vet says okie dokey).
  • Add catnip to food.
  • Add warm water.
  • Add just a pinch of dried shaved bonito (tuna) flakes to give your boring meal a little zest.

Treats you can try include:

  • Whole meat baby food. Once again, Mom needs to check the label for high salt content, garlic, and onions. Baby food should only be used as a treat, since it lacks taurine and other essential nutrients.

Avoid foods or treats containing:

  • Foods high in sodium.
  • Garlic and onions — they cause Heinz hemolytic anemia.
  • Grapes or raisins, since they can cause kidney damage even in healthy cats.
  • Citrus fruits because they’re used in commercial cat repellents and it can also upset our tummies.
  • Soybeans because of the high protein content.


You also need to stay hydrated. A cat water fountain provides you with fresh-tasting, aerated water and encourages you to drink it. Add tuna water or chicken broth to make water taste better. The water should be changed daily, especially if you add flavor to it.

Hopefully with the help of your mom and your vet, your appetite will ramp up and your waist will fill out. At some point, your kidneys will say, "Hasta la vista, baby." Then, sadly, it might be time for your mom to read “The Feline Quality of Life Scale Helps You Determine If It’s Time to Say Goodbye to Your Cat.”

Read related stories on Catster:

Got a question for he who knows everything feline? Just Ask Einstein in the comments below and you might be featured in an upcoming column. (Letters don’t have to be written from the cat’s point of view.) Remember, any change in your cat’s behavior or activities could be a symptom of disease and should be investigated by your vet, even if it unfortunately involves glass tubes and cat posteriors.

About the author: Einstein’s assistant, Dusty Rainbolt ACCBC, is the vice president of the Cat Writers’ Association, editor-in-chief of and a member of the International Association of Animal Behavior Consultants. She’s the award-winning author of eight fiction and non-fiction books including her most recent paranormal mystery, Death Under the Crescent Moon.

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