Some dog owners are under the misconception that dogs are primarily carnivores, so they feed their dogs protein-rich, grain-free food. Other pet parents go the homemade route and cook high-protein people-grade food for their dogs. Add to that the raw meat movement. The common factor: All of these diets are high in protein.

Think about the “too much of a good thing” proverb when feeding your dog. Dogs, like us, are omnivores and actually do best when they eat a balanced diet of protein, carbohydrates and fat.

The problem with too much protein

Veterinarians see severe health conditions in dogs fed homemade diets consisting solely of meat. A significant issue is the lack of calcium. Simply put, bones, even dogs' bones, need calcium. “Veterinarians see dogs who have been fed mostly meat come in with fractures throughout their skeletons,” says Louise Murray, DVM, DACVIM, vice president of the ASPCA Animal Hospital. “At that point, changing their diets is often too late. It takes a long time to restore bone strength.”

Related: Is Your Dog’s Food Making Him Sick?

Experts once believed high-protein diets caused kidney trouble, but recent studies cast doubt on that theory. “An early study stating that too much protein causes kidney damage is being debunked,” says Murray. “And that early study didn’t even involve dogs. That study was done on rats, and rats are basically plant eaters, not meat eaters. Dogs, just like us, are omnivores, and we’re both quite flexible when it comes to eating protein or going vegetarian.”

Dogs generally need protein to consist of 20 to 30 percent of their diets, according to Murray. But it’s hard to tell what percentage of a dog's daily protein needs a serving contains. “Labels list the minimum [required daily] amount of protein, but don’t tell you the actual percentage” says Murray.

“Speak to your veterinarian about your own dog’s ideal dietary composition including protein levels,” says Murray. Your dog’s veterinarian will take your dog’s size, breed, age and activity level into account. “For healthy dogs, there is an acceptable range. For those with medical conditions, your vet may have specific recommendations.”

Related: 10 Foods You Should Never Feed Your Dog

A focus on phosphorous

If your dog does have kidney disease, “the focus is now more on restricting phosphorous than protein,” says Murray. Meat is high in phosphorous, and excess phosphorous may accelerate the progression of kidney disease. Dogs need a healthy balance of calcium and phosphorous, and this is particularly essential in canines with kidney disease.

Cats and protein

The rules change dramatically when it comes to cats. They must eat a protein-rich, meat-based diet, which should be carefully balanced for their strict nutritional requirements. For example, unlike dog food, cat food must contain taurine, an amino acid which cats are unable to manufacture.

Related: 8 Common Cat-Feeding Mistakes to Avoid

Michele C. Hollow writes about pets and wildlife. She is an award-winning journalist who has written for The New York Times, The New York Daily News, and other leading publications. She blogs at Pet News and Views.