Why Dog Food Is For Dogs and Cat Food Is For Cats

Is it dangerous to feed dog food to your cat? What about vice versa? Ever wondered why some pet foods have cats on the packaging… while others only offer us dogs?

It may sound silly to you, but plenty of people ignore the pics and labels altogether, apparently laboring under the illusion that as long as there’s a furred and four-legged creature on the side of the bag or can it’s bound to be acceptable fare for either species.

Not so. Which brings me back to my original question:

Q: Did you ever wonder what, exactly, separates a cat food product from its canine varietal?

A: It’s an important question not just because there are yahoos out there willing to feed their pet anything or because you may one day find yourself in a pinch (Can I feed Fluffy some of Fido’s food or do I have to go shopping right now?), but also because understanding the differences can help teach you a thing or two about your pets’ nutritional needs.

How Dog and Cat Foods Are Different

Consider the major points that differentiate dog foods from their feline counterparts:


Dogs and cats perceive food differently. For example, among other differences, cats don’t have the ability to taste anything sweet. Their reduced range for what they consider palatable helps explain why dog food doesn’t tend to attract cats as much as cat food does dogs.

Vitamin A

Dogs have the ability to turn beta carotene into Vitamin A, a feat cats’ bodies can’t manage. That’s why Vitamin A must be supplied in cat food. While plenty of dog foods may contain additional vitamin A, they aren’t necessarily formulated to offer the amounts a cat requires for a lifetime of optimum health. A variety of non-specific symptoms and disease states can result when cats don’t receive sufficient levels of Vitamin A in their food.


Taurine is considered an essential amino acid for cats. Therefore, all cats require it. Dogs, on the other hand, can make their own taurine, which is why many dog foods are deficient in this nutrient. If a cat is fed a canine diet lacking sufficient levels of taurine, blindness and a heart disease called hypertrophic cardiomyopathy are the most common outcomes.
Note: Taurine deficiency also happens when cats eat a fish-only diet, since fish meat is largely deficient in this amino acid. Which is why you might’ve heard that tuna is “bad” for cats (but isn’t unless you’re not feeding an otherwise balanced diet).

Arachidonic acid

Arachidonic acid is a fatty acid dogs can build themselves. Cats, on the other hand, require the real thing. Cats who eat dog foods low in arachidonic acid levels will suffer a variety of nonspecific symptoms.


Total protein levels in dog foods tend to be lower than for cat foods. This represents another significant reason not to feed our felines food that’s meant for dogs. Though some dog foods do offer very high levels of protein, most don’t offer the percentage of protein our carnivorous cats require.

In recent years, much has been made of the protein quality and quantity due our cats as part of their normal nutritional requirements. In academic circles, this topic is hotly debated. Let it suffice to say, however, that the protein requirements of obligate carnivores like cats are superior to those of dogs and that cats who consume dog-level protein levels on a regular basis will fail to thrive at rates comparable with their peers.

Questions & Answers

Q: So is it truly terrible to feed your cat the dog stuff if you happen to run out and the shops are all shuttered?
A: Well… no, not really. As long as a) your cat will eat it, b) it’s temporary, and c) your cat is otherwise healthy, dog food is unlikely to harm your cat one bit.

Q: But how about your dog?
A: From the above five points, we’ve effectively established that cats can’t live off dog foods but dogs can eat the cat stuff until the cows come home. Theoretically, anyway.

But while a dog can live on cat food alone, anyone who’s tried it will likely agree that it’s not an advisable activity. The caloric density, high protein levels, and heavy doses of fat aren’t ideally suited to all canine gastrointestinal tracts – much less to their waistlines.

Obesity is probably the worst thing most dogs will get from eating the kitty stuff, but diarrhea, vomiting, and even potentially life-threatening pancreatitis are possible when you feed cat food to dogs (for some sensitive dogs, even after one single meal).

The moral of the story? Dog food is for dogs and cat food is for cats. In fact, if you’re that hard up for your pet’s food, consider a small amount of bland “human food” as an alternative (if you already know what works).