Are canned and kibbled created equal? (The feline dry vs. wet diet debate)
I tend to talk a lot about kibble-feeding in cats. As in, play catch with the kibble by throwing it across the floor. If you do this often enough, it’ll help whittle away her sagging waistline, I say.
Recently, some of you have reprimanded me: “You’re recommending ‘kitty crack’! Everyone knows dry food is bad for cats!” But is it really?
Pound-for-pound, kibble has always out-sold canned cat foods. Its convenience, after all, is unmatched by any tinned food’s tendency to dry out and decay. Its price is generally nicer. And the extra step of spooning it out into the right serving size seems so passé when scooping and storing the crunchies is so simple.
Yet as some of you have pointed out, there’s more than a reasonable doubt that the average kibbled cat food is more appropriate for most cats than the canned stuff.
Why? Here’s what some proponents of a more “biologically appropriate” feeding approach have to say about feeding our household felines:
- Cats are desert-originating carnivores designed to require more moisture in their food than most. Even their hairy tongues show they’re not well suited to lapping up liquids.
- Cats need the higher protein and fats canned foods tends to carry. These diets approximate the consistency of a cat’s natural diet more than any kibbled food.
- By design, dry foods employ far more carbohydrates, a nutrient category carnivorous cats cannot utilize in the same way we omnivores can.
These issues provide the fundamental rationale for why an increasing number of veterinarians and veterinary nutritionists believe cats are better off fed wet foods over kibbled ones.
Sure, cats can make up the water elsewhere (which is why I love running water drinking fountains for cats), but not all will. Far more critical, perhaps, is not the moisture itself, but what’s possible therein.
Because making kibbled food is hard to do without adding starchy stuff, canned diets can offer more protein and fat and fewer carbs––which cats decidedly don’t need in abundance. (Felines are obligate carnivores, after all.) And this, the issue of protein and fats vs. carbohydrates may be more critical to cats than we previously believed––that is, until some veterinary nutritionists began researching this issue about twenty years ago.
What these nutritionists believe they discovered was that cats cannot properly utilize proteins in the presence of too many carbohydrates.
“Although cats can use [carbohydrates] as a source of metabolic energy, they have limited ability to spare protein utilization by using [carbohydrates] instead,” wrote Dr. Debra Zoran in a 2002 JAVMA article now often touted as the seminal biochemical argument in favor of more biologically appropriate feline diets.
Therefore, it’s posited, cats must eat more of the carb-rich foods to properly assimilate the proteins these provide. This is no doubt a drastic oversimplification of this body of thinking, but it should suffice for our purposes. Anyone who’s interested in the biochemical underpinnings of feline carnivore-dom should read Zoran's article (sorry about the formatting but this way it's free).
Yet manufacturers of kibbled cat foods––along with plenty of naysaying veterinary nutritionists––contend that by now we’ve come to terms with what nutrients cats need in their foods. As long as we provide the right amino acids, vitamins and other fundamental building blocks, carbs don’t really matter. Unused carbs will just pass right on through or ferment in the GI tract to provide an extra source of nutrients. Even carnivores can handle carbs and vegetable-based proteins, they say, adding that crunchy is good for teeth, too!
But here’s what the wet food proponents offer:
- Crunchy diets may help teeth, but not by very much. Brushing is the right way to deal with periodontal disease.
- With kibbled diets, cats are effectively forced to eat more, making obesity a likelier outcome.
- Moreover, the convenience of feeding kibble has made portion control harder for those who would feed it free choice (and so many do).
- The utilization of unnecessary carbohydrates means that diabetes risks may be higher for those who subsist on a kibbled diet alone.
- Sick or injured, under-eating cats will be more likely to suffer malnutrition if they eat kibble since they’re effectively protein-starved in the presence of all those carbs.
- Further, fatty liver disease is more likely in overweight, kibble-fed cats who suddenly under-eat, since protein malnutrition triggers body fats to break down preferentially to feed the starving body.
- Cats who do not get enough moisture in their food may not make it up by drinking, thereby taxing every organ system in the body, most notably the kidneys and the urinary tract in general.
It all kind of makes sense, doesn’t it? Though it’s indeed possible for a cat to live a perfectly long life on kibble alone, cats who do not drink sufficiently and/or cats with predispositions to certain diseases (like diabetes, obesity and any sort of disease process that should cause them to under-eat) are theoretically at a huge disadvantage if they live on kibble alone.
But here’s the problem: It’s all still theoretical. In other words, studies have not yet teased out the truth of the matter. For every study that points in the direction towards wet (or even raw), another debunks it in favor of dry's acceptability. Here’s a 2008 veterinary nutritionist’s rebuttal to the wet food arguments, particularly with respect to diabetes in cats. It’ll give you an idea of how wide open the debate remains in veterinary circles.
Some suggest this degree of resistance to a highly commonsensical concept is the pet food industry’s doing, what with all their money going towards the furtherance of highly processed foods at all costs. And the cynical me suspects there’s some truth there. After all, the vast majority of our pet nutrition research has historically been dependent on the pet food companies’ dollars.
So when it comes right down to it, I can’t rightly say whether a dry food is truly inferior to a wet one––nor can anyone who guides themselves by the morass that is the current state of our feline nutritional research. But if I’m to put my money somewhere, it would almost certainly favor the kind of food that more closely resembles the real thing.
Because if there’s one thing I DO know, it’s that mo’ processed is NOT mo’ better. Not that we can’t live long, healthy lives stuffing ourselves and our family members with highly processed, machine extruded foods, but I’ll always take the closer-to-reality approach should I get a choice in the matter.
Too bad that means the best feline feeding options still look one heck of a lot more like a bird in a blender than anything else.
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