THE CAT FOOD CONTROVERSY
Is dry or wet food better for your cat?
By Stacy E. Smith

The Theory

First and foremost it is important to remember that your cat is a carnivore in the truest sense of the word and requires a meat diet just like a lion or tiger. This fact is often either completely unknown or all too often overlooked by cat owners (not to mention food manufacturers). Although there are as many opinions as experts, there are actually some experts out there that believe some people are making their cats sick with the food they give them. Depending on what you feed your cat of course, this is probably an exaggeration, but it does bring attention to the question of what type of food our pet cats should be eating.

Dogs, while essentially carnivores, are omnivorous to a large degree, and have the ability to break down and digest vegetable as well as animal protein. A dog can actually survive quite successfully on the same foods humans eat, which is why dogs can live on table scraps, garbage from behind restaurants (if they must), or even a carefully balanced vegetarian diet (I had a roommate with a Bernese Mountain Dog that was actually allergic to meat), especially if supplements are added.

Despite 5000 years of domestication however, cats remain strictly carnivorous. There are no vegetarian cats; probably because they don’t digest and receive nutrition from the majority of vegetable proteins very well. (Although I recently witnessed one of my cats inexplicably steal a rather large, cooked broccoli floret from the kitchen counter and eat the entire thing). However, cats in the wild actually devour their prey in its entirety (muscles, organs, bones, fat, stomach, intestines, etc.); ingesting not only the flesh and organs of their prey but also the partially and wholly digested vegetable foods their prey had previously eaten. With the assistance of the prey's own digestive processes, the cat is then able to derive nutrition from various vegetable sources.

Although many people rely on dry cat food as a staple for their cats' diet, canned cat food is an important component of a cat’s diet and may help prevent many potential conditions caused or contributed to by an all-dry cat food diet – especially if the cat is predisposed to those conditions. It's true that dry cat food is convenient; it is less expensive, stays fresh for a long time, and most cats like it. However, dry cat food has a "downside." Cats that eat a diet of dry food alone may be losing out on the extra nutrition they can get with canned cat food. Many commercial dry foods are packed with carbohydrate fillers, none of which have any value to a cat. In the wild, a cat will eat only a very small quantity of any grain; whatever is contained in the stomachs of the mice, rabbits, or birds she catches. So, why should a pet cat eat a diet that is loaded with stuff she really doesn't need? And then there is the issue of moisture – dry food obviously doesn’t have much.

The Cats Must Be Thirsty

Water is vital to good health and the lack of moisture in dry cat food can be a big problem for some cats. Cats that don’t get enough water/moisture in their diet can be chronically dehydrated which can lead to a variety of health problems. The natural prey of a wild cat contains between 65 and 75 percent water, dry food averages 10 percent and canned food averages 78 percent – do the math. Of course a daily supply of fresh water should be made available to your cat, but she can’t necessarily be counted on to drink enough of it. It is even suspected by some that cats may not have a strong thirst drive compared to other mammals. (I said, “…suspected by some…” – that means it is an opinion held by some people and doesn’t mean it is necessarily a fact.) The real issue with not drinking out of the water bowl may really be that people don’t change the water often enough – cats are really particular about EVERYTHING. Your cat may prefer your toilet to her water bowl if it isn’t changed daily. There is a rule of thumb proposed on Purina’s website that says if you feed your cat dry food, she should consume approximately one cup of water for every ten pounds of body weight in a twenty-four hour period. If you feed canned food, her intake may be one-third to one-half of the above. If the weather is warm or she is playing or running a lot, she may drink more. Either way it is critical that they get plenty of moisture and their food is just as good a place as any for a cat to get it.

Although there are those that will argue that all of this is completely unfounded, it is believed by some that feeding a dry diet alone to a cat can contribute or be directly related to certain health conditions, especially, as mentioned previously, if a cat is genetically pre-disposed to them. These conditions include: Inflammatory Bowel Disease (IBD), Dehydration, Chronic Renal Failure (CRF), Urinary crystals (potentially fatal to cats), Obesity and Diabetes. Unfortunately, there is no test that shows whether or not a cat has a pre-disposition for any of these things, although a known family history of such conditions may be a good indicator.

Is Raw Food Better?

Maybe yes, maybe no. Raw food is exactly what cats eat in the wild. A study done in the mid 20th century showed evidence that a cooked meat diet (both dry and canned pet food is cooked) caused physical deterioration in cats and their offspring over a period of time. However contemporary experts now believe it was the lack of taurine, rather than the cooking that caused the nutritional deficiencies cited. Adding taurine to the diet has since become a common practice in commercially prepared cat food; canned, raw and dry.

While there are plenty of feline nutrition experts that recommend a raw meat diet for cats, as always there are plenty that don’t think it is necessary. Additionally, this isn't always a feasible option for a great many cat owners. Other experts recommend canned or raw food as the cat’s primary diet; with dry food set out for “grazing” in between. Still others are so convinced that dry food is bad for cats they suggest that dry cat food should only be reserved as "treats," to be given out a few pieces at a time – again, another opinion.

For what its worth, after doing the research for this article, we now give our cats a portion of canned or raw food every day, and as mentioned above, leave dry food out for them to eat at will.

What Vets Say

Just like with anything, there are varying opinions and ways individuals practice their craft, so too goes veterinary medicine. I spoke to a few veterinarians and here’s what they had to say:

Eliza Sundahl, DVM, at the Kansas City Cat Clinic (Kansas City, MO) recommends a diet that is 50 percent canned and 50 percent dry. She suggests that not only is the moisture content in canned food helpful, but feeding both types of food helps cats get used to variety in their diet and can be a plus when needing to mix medication in your cat’s food or if it becomes necessary to change their diet at some point.

Tony Buffington, DVM, PhD, DACVN, Professor of Veterinary Clinical Sciences at The Ohio State University Veterinary Hospital (Columbus, OH) spoke to me at great length and has an interesting theory that links a cat’s stress level in the home to urinary tract problems in cat already susceptible to them in the first place (check out www.indoorcat.org for more information). However, with regard to diet in the management of idiopathic cystitis (inflammation of the urinary bladder) specifically he does not believe “that dry food consumption causes IC, but dry food consumption might unmask or aggravate the disorder in susceptible cats (making IC a nutrient-sensitive rather than a diet-induced disease).” He therefore recommends “either adding water to the dry food or changing to canned foods (particularly if the cat is male because of the risk of urethral obstruction) if this is feasible for the owner and the cat. Benefits of increased water intake could include dilution of any noxious substances in urine, more frequent urination to decrease bladder contact time with urine, and removal of any excess crystals.” He also recommends “that the same diet be fed for extended periods of time to reduce the stress that some cats seem to experience when the diet is changed.”