Sadly, estimates are that over half of kitty companions over the age of 10 suffer from chronic kidney disease (CKD), which is also referred to as chronic renal disease or chronic renal failure. There are many causes of CKD in cats, but one of the most common and preventable influences is a dry food diet.

Cats are designed to meet most or all of their body’s moisture requirements through their diet, not at the water bowl, so they don’t have the desire to drink water the same way other species do. Kibble provides a very small percentage of the water cats need in a daily diet.

Kitties fed an exclusively dry diet suffer chronic mild dehydration that causes significant stress to kidneys over time. As Dr. Lisa Pierson, a feline-only practitioner and cat nutrition expert, writes at her fabulous CatInfo.org website, “It is troubling to think about the role that chronic dehydration may play in causing or exacerbating feline kidney disease.”

Dr. Pierson’s Big Three Nutrition Messages for Cat Guardians

Dr. Pierson realizes that feline nutrition can be overwhelming for cat guardians, and tries to keep things simple. Her recommendations are based on what a cat would eat in the wild – a mouse, bird, lizard, or some other small animal.

1. Feed a diet that’s high in moisture.
   Dry food (kibble) is cooked to only maintain 5-10% moisture, whereas a bird or mouse is around 70% moisture. When a cat is fed a dry food, they don’t make up that deficit at the water bowl.
   Now, many people say, “but my cat drinks a lot of water.” Studies of cats on all-canned food diets vs all-dry food diets show that cats eating canned food (which has a very high water content) rarely went to the water bowl, yet they consumed double the amount of moisture as cats eating kibble. The kibble fed cats did not demonstrate a high enough thirst drive to make up the water deficit at the water bowl. A water-rich diet, like canned or raw food, is the first key to a healthy diet.
2. Feed your cat a diet that’s animal-protein rich.
   Cats are obligate carnivores, and must get their dietary protein from animals, not plants. When we look at a can of cat food, we want to see that the protein is coming from animals – chicken, beef, etc. – and not from plants like corn, wheat, soy, or rice.
3. Avoid carbohydrates.
   Cats aren’t designed to eat carbohydrates. A bird or a mouse is a very high-protein, moderate-fat meal, with maybe a percent or two of carbs on a dry matter basis. So diets containing more carbs aren’t appropriate for cats.

It’s also important to remember that although high-protein, low carb dry cat foods are flooding the market these days, they are inappropriate diets for cats because they’re water depleted. Many cats suffer from Urinary Tract Disease, and it is caused by urethral obstructions from a water-depleted diet. Cats on water-rich diets can develop UTIs as well, but it’s extremely rare.

What’s the Scoop on Prescription Diets?

Once a cat is diagnosed with chronic kidney disease, many veterinarians recommend a prescription “renal diet,” many of which are dry kibble. These formulas do not meet the dietary hydration requirements of cats, especially kitties who are losing large amounts of water due to worn out kidneys.

“I must say that I find it truly amazing when I hear about the very large numbers of cats receiving subcutaneous fluids while being maintained on a diet of dry food,” writes Pierson. “This is an extremely illogical and unhealthy practice and every attempt should be made to get these cats on a diet that contains a higher moisture content.”

Prescription renal diets also typically have reduced levels of protein, which is not ideal for cats, who are obligate (strict) carnivores requiring high levels of quality animal protein for optimal health. According to Pierson:

“Renal diets restrict protein to the point that many cats – those that are not consuming enough of the diet to provide their daily protein calorie needs – will catabolize (use for fuel) their own muscle mass which results in muscle wasting and weight loss.”

Pierson also points out that interestingly, there’s no FDA oversight of prescription pet diets. They oversee drugs, but these diets are marketed as “prescription,” when there’s nothing in them that requires a prescription. Clinical trials aren’t performed before these foods go on the market, and could be formulated in a far healthier manner if these “prescriptions” underwent much closer scrutiny.

Why Veterinarians Recommend Prescription Diets

Dr. Pierson focuses on helping cat owners formulate diets that are customized to that cat’s individual needs. She says that it’s extremely common that people are hesitant to feed a wet food rather than the “prescription” food another veterinarian recommends. Her clients are commonly led to believe that the only diet option for a kidney sensitive kitty is a prescription diet.

Pierson says that unfortunately, veterinarians are extremely busy trying to keep up with their continuing education, and nutrition is typically not very interesting to most of them. It’s much easier for a vet with a feline kidney patient to simply grab the “prescription” diet off the shelf. There isn’t a lot of critical thought going into nutrition for pets.

Switching Your Cat to a Better Diet

The transition to wet or raw food from kibble can be surprisingly difficult. Cats that have eaten dry food for most of their lives can become addicted to it. And cats, unlike dogs, will literally starve themselves if you aren’t feeding what they prefer.ca

Dr. Pierson refers her clients to the page on her website called Transitioning Dry Food Addicts to Canned Food. She encourages cat guardians to have patience, as it took her three months to get her own kibble addicts to switch to canned food.

If you’re first getting started, try a variety of proteins and textures in wet food. See if you can get your cat to respond positively to one or more, and gradually transition to an all-wet diet. And remember – patience, patience, and more patience!