Hang around a fancy boutique pet store long enough and you may run into a bizarre and confounding creature – the pet owner or animal rights advocate who feeds his dog or cat a primarily (or even exclusively) vegetarian diet.

These curious critters come in all shapes and sizes.  And while some are elitist snobs, others are total sweetie pies.  Indeed, their only defining characteristic is that they all generally have absolutely no idea what they’re talking about.

They’re usually not bashful about making that perfectly clear for you.  If you give one of these folks a chance (I don’t recommend it), he’ll probably explain the thinking supporting his dietary decision-making.  And his explanation will probably include some variation of the claim “a vegetarian diet is good for cats and dogs.”

Please allow me to be brief: he’s wrong.  And the purpose of this article is to explain why he’s wrong.  Our aim is to provide you with the information necessary to blow this myth out of the water so that the next time you run into one of these goofballs, you can tell him yourself why he’s wrong.

It may seem cruel or cynical but please trust us, his dog or cat will thank you for it.

Vegetables Are Not The De Facto Better Food For All Animals To Eat

When considered next to meats, vegetables are wrongly perceived by many people to be the de facto “healthier” food option for all animals.

Choose your preferred explanation for this tough-to-deny phenomenon: the idea was planted in our heads during our youth (“eat your vegetables!”), we’re looking for reasons not to eat the animals whose suffering stirs our emotions (i.e., the “cute” ones), our simple minds need simple rules to guide our behaviors, sensationalist journalists commonly misinterpret and overblow scientific findings concerning dietary health, blah, blah, blah.  Pick whichever story works for you – the real answer is probably impossible to identify specifically and it’s not important anyways.

What is important is the accuracy of the perception.  And that’s where we come in.  There are two big problems with the notion that vegetables are de facto “healthier” food option for all animals: (1) it’s overly simplistic and (2) it’s narrow-minded.

It’s too simple because the concept of “healthiness” is vague.  In reality, every decision we make (dietary or otherwise) impacts us in both positive and negative ways.  In the context of dietary decision-making, most of the things we eat do both good things and bad things to our bodies (that being said, please don’t run off and eat a handful of mulch or a plate of Nachos Bell Grande because we told you it would at least do “something good for you”).  Eating a stalk of broccoli instead of a steak may provide your body with more of the insoluble fiber that the body needs to operate most efficiently and effectively, but it will also provide the body with less of the protein that it needs to reach its full potential.  And so it goes with any either/or dietary decision.  It’s not just a zero sum game.

A more useful and honest health-focused analysis of dietary philosophies must look beyond the vague concept of “healthiness” and focus on specific health-related variables: body weight and composition, longevity, specific pathology avoidance, energy and vivacity, mobility, mood, etc.  And we must attempt to determine what we’re trying to achieve before we decide what foods will help us to achieve it.  Because the answer isn’t always going to be the same – sometimes substituting vegetables for meats will help you achieve your specific health-related goals, other times it won’t.

For purposes of this article, the more important criticism of the “veggies are always healthier for everyone” position is that it’s too narrow-minded.  Specifically, this perspective ignores the tremendous biological diversity that exists among the world’s food-consuming populations.  In other words, while eating veggies may be “healthier” for some animals, it isn’t necessarily healthier for all animals (or all non-animal organisms for that matter).

If you accept the “theory” of Darwinian evolution then it’s really not a difficult concept to understand.  Some organisms (they’re called “carnivores”) have evolved to derive their energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue.   Some of these guys (a sub-set called “obligate carnivores”) will die or suffer severe functional handicaps if they’re not fed meat or a diet supplemented with synthetically-produced meat-borne nutrients on a regular basis.

Take, for example, the simple case of domestic cats. Cats are obligate carnivores because they need to ingest the nutrient taurine regularly in order to perform a number of critical biological functions (they can’t manufacture taurine themselves) and plants don’t contain adequate amounts of taurine to support their needs. Accordingly, an un-supplemented vegetarian diet is most certainly not “healthier” for cats than a meat-based diet.

Nor is it for any other obligate carnivore species.  And, if you follow this line of reasoning, nor is it for any species that lacks the psychological and physiological traits necessary to ingest, digest, and metabolize plant matter.  And that’s why it’s dangerously narrow-minded to claim that vegetables are a de facto “healthier” food option for all animals.

Dogs Are Not Omnivores

Dogs are not obligate carnivores – they are more adaptable than cats and their bodies won’t immediately break down if they are fed an un-supplemented vegetarian diet .  But that doesn’t mean that they’re omnivores.

Omnivores – as you may remember from your high school biology class – are organisms that display biological adaptations which allow them to ingest and digest both plant and animal matter.  They are generally opportunistic feeders that have evolved to eat whatever happens to be available.  As a result, most omnivores actually depend on eating a suitable mix of plant and animal food to support their optimal long-term health and reproduction.

You can identify an omnivore by analyzing its physiology.  They tend to have large, flat molars that are useful for grinding up veggies.  They tend to secrete salivatory enzymes that begin digesting starchy vegetables while they are still being chewed.  Their bones and muscles are adapted for grazing, gathering, and slow movement, not hunting, chasing, pulling down, killing, and ingesting other animals.  And their digestive tracts tend to feature long colons and small intestines that allow them to process tough-to-digest starchy vegetables.

Now lets’ take a look at your dog’s physiology:

Start with the teeth.  A dog’s teeth are quite obviously adapted for ripping and shredding, not grinding. Most of the teeth are sharp and pointy.  Even the molars are pointed and aligned like scissors.  Contrast them with a true omnivore’s teeth, such as your own or those of an American Black Bear and you’ll immediately see very obvious differences.

Move beyond the teeth and look at its musculature and structural anatomy.  What movements do most healthy dogs perform absurdly well? Running (chasing down prey), jumping (pulling down prey), chomping (ugh, this device might get a little graphic if we continue…), crushing, shaking, GRRRR!!!! They’re practically prey-hunting machines!  They’ve got heavy skulls, jaws that hinge open widely, strong neck and jaw muscles, and powerful leg and hip muscles.  (Honestly, I don’t know how can anyone play fetch with a healthy adult dog and fail to see its carnivorous adaptations on full display.)

Lastly, consider your dog’s digestive anatomy.  Its stomach is large and elastic, designed to hold large quantities of flesh.  But the stomach is also relatively simple and the digestive tract is short.  Indeed, your dog’s digestive tract is so short and simple that it actually cannot meaningfully digest most raw vegetables (that’s why even advocates for vegetarian diets will tell you that you need to cook your dog’s veggies before feeding them).

I challenge anyone to look critically at the physiology of a domestic dog and try to build an argument that the animal is omnivorous by evolutionary design.  The idea seems absurd to me.

But, if you need further convincing, spend a few minutes thinking through these comments about the natural diets of wolves and wild dogs:

According to the Wisconsin Department of Natural Resources, the Timber Wolf (the dog’s closest living relative) diet is comprised of 55% white-tailed deer, 16% beavers, 10% snowshoe hares, 19% rodents and other small mammals.

…

According to the University of Michigan Museum of Zoology, feral domestic dogs eat small animals as their main source of food. During tough seasons when meat is harder to come by, wolfs and wild dogs become more opportunistic, eating eggs, fish, fermenting fruit, seeds, nuts and grasses to supplement the meat that they are able to catch. This adaptability is another beneficial survival tactic although dogs cannot sustain themselves forever on these limited food sources.

As I mentioned before, like wolves, dogs are adaptable enough to survive on certain plants (and even synthetic junk food – yuck!) in tough times.  That doesn’t mean that plants are their optimal energy source or that plants are the “healthier” food option for them.  It just means that eating plants is a better option for them than dying of starvation.  You don’t have to be Ranger Rick to know that wolves don’t eat plants if there are other options available.  And dogs share 99.8% of their DNA with wolves.  Just why on Earth would anyone think that it’s “healthier” (no matter how you define that word) for them to eat plants?

Phew.  Hopefully that’s enough ammunition for you to take on anyone who claims that dogs and cats should be fed a vegetarian diet.  And, in any event, that’s certainly enough ranting and raving for a Friday.  I hope that you and yours all have a great weekend.

Cheers,

– Coach Dan