Cats are a rather peculiar species. In a lot of aspects, dogs are similar to people. We can take many of the same medications, we have similar behavior patterns, we eat similar diets, and we even get (and sometimes succumb) to many of the same diseases. Not so with cats. Many human medications (even over the counter ones like aspirin) can be highly toxic to cats. Anyone who claims to understand cat behavior is either fibbing or a very unusual person! Cats can and do get many of the same ailments as people, but they also have a long list of things that are unique to them (or at least occur at a much, much higher rate). And finally, cats are true carnivores, whereas dogs and people are omnivores.

Being true carnivores, cats eat a diet that is much higher in protein than that of dogs or people. If for no other reason, this is why cats should only eat a high quality cat food. But there are also several other very important reasons, too. One of the most important reasons, for feeding good cat food is that cat bodies are incapable of making taurine, which is an essential amino acid. Dogs and humans are able to make taurine from other proteins we consume, but cats must have the entire protein in their diets regularly. If cats are fed low quality cat food or especially homemade diets, they often don’t get enough (or sometimes any!) taurine. Taurine insufficiency very quickly leads to the development of dialated cardiomyopathy, a deadly disease that causes the heart muscle to become stretched and weakened.

A second very important reason for feeding high quality cat food to cats is that they don’t metabolize magnesium and phosphorus as well as people and dogs do. Most meat sources are fairly rich in those minerals, so it actually costs more to take them out of cat food than it does to leave them in (and you can’t take them out of homemade diets at all). For this reason, many of your least expensive cats foods contain too much of these minerals. Feline kidneys filter the excess out and get rid of it in the urine. If the urine is concentrated enough, and the pH is right, those excess minerals will form stones and those stones can get stuck in the urethra (the tube that leads from the bladder to outside) and then the animal can’t urinate. This is extremely painful, and can be lethal if it goes on for very long.

Because of their high protein diet, cats should always have access to clean, drinkable water. We all need water, of course, but carnivores require more than most omnivores. The kidney of a carnivore works harder than that of an omnivore, so even mild dehydration can result in kidney failure. In the wild, before domestication, cats were desert dwellers and did not drink much water. The reason that this worked okay for them was that their prey provided them with all the water that they needed (remember, most bodies are 80-90% water). In today’s world of dry kibble or even most commercial canned food, there just isn’t enough fluid for their needs.

Finally, let me touch on one more problem we are seeing more of since so many people have begun feeding homemade diets. That is metabolic bone disease. It has long been a problem in captive large cats since they are often fed commercial cuts of meat rather than whole prey, but it had been pretty well eliminated from domesticated cats, even those eating very inexpensive foods. Metabolic bone disease is caused by a lack of calcium in the diet. Over time this weakens the bones and causes them to fold (called folding fractures), to grow abnormally, and/or to break. Just adding calcium alone won’t do the trick, either. It needs to be balanced with potassium and other minerals as well as certain vitamins.

In summary, please be careful about what you feed all of your animals, but particularly cats. My recommendation is a good quality commercial cat food. Stay away from really inexpensive ones (but you don’t have to spend an arm an a leg, either), and stay away from “designer” foods and homemade diets. If you are absolutely set on changing your cat’s diet, consult your veterinarian first. If you veterinarian recommends a prescription diet, please follow that advice. Cats can live a very long time if well fed and well cared for. And, in the long run you will save money, too. Veterinary care for any of the above mentioned ailments ain’t cheap!