Just another buzz phrase? It may sound complicated, but it's only common sense: it means a diet that is appropriate for the species. From the physical attributes of teeth and jaws to the chemistry of stomach acid to the length of the intestines, dogs and cats are quite different from humans. Even though dogs have been living with us for 40,000 years, and cats nearly 10,000, they still have very different nutritional requirements than we have. They are indeed as different from us on the inside as they are on the outside, which is why should their diet be different.

When you look at the anatomy of dogs and cats you’ll see some major differences from humans. These differences scientifically classifies dogs and cats as carnivores:

  • sharp teeth designed for tearing and ripping, not grinding
  • jaws that only move vertically, again to support tearing and ripping, not grinding
  • the natural pH of their stomach acid is 1–2 (pretty acidic), lower than ours
  • very short GI tract resulting in short food digestion transit time:
Dog = 12-30 hours
Cat = 12-24 hours


How should their diet be different? Biologically appropriate diet for dogs and cats are:

  • comprised mainly of whole meat, organs, and bones with other ingredients such as fish, eggs, fruits, and veggies to ensure nutritional completeness
  • higher in protein
  • moderate fat (unlike humans, fat dogs and cats efficiently use fat as energy)
  • little to no carbs (natural prey, like rabbit and birds, are only 9-10% carb)
  • 70–75% moisture

As you see, a steady diet of plant-based food isn’t the optimum diet for dogs and cats. Since most of us don’t want to send our dogs and cats out foraging for their natural diet, what should we feed? Ideally, a raw diet such as Primal, Stella and Chewy’s, Nature’s Logic, Northwest Naturals, or Rad Cat would be your first choice.

But for some people raw isn’t ideal either because of the cost of feeding a large dog (or a couple of dogs) or raw just isn’t for them. The next best option is a freeze-dried or dehydrated diet. Primal, Stella and Chewy’s, and Northwest Naturals diets are available in a freeze-dried raw* form so all you need to do is add water to make a healthy meal. Although most of us know that Orijen is a top-notch kibble, several of their formulas are now available in a freeze-dried raw form.

Other convenient yet healthy options include Grandma Lucy’s, The Honest Kitchen, and Sojos. These companies make complete diets as well as base mixes, which are a good solution for the dog that needs a novel protein or the owner who wants to be sure of the quality of the meat.

As if there aren’t enough alternatives to raw frozen, there are air-dried diets available from The Real Meat Company and ZiwiPeak. These diets are ready-to-eat right out of the bag and are primarily meat and organs that are gently air-dried.

And finally, last, but not least, on our list of biologically appropriate dog and cat food is high quality kibble such as Orijen and Acana, which have been formulated to meet the proportion of meat, organ, bone, and plants that match the natural diet dogs and cats .

Even though life with humans has resulted in dogs and, to some extent, cats having evolving to adequately digest a variety of food, it doesn’t mean that they will thrive on highly processed foods. Still not sure what to feed your pet? Look at what their wild counterparts eat.


*Note: Many people consider food to be raw only if its preparation consists of simply chopping and mixing in a manner that does not generate heat.