Dear Daisy Dog: Our dog Breck eats 60 percent cooked meat and 40 percent grain-free dry food. I read your column about the risks associated with grain-free diets, but since Breck eats so much meat, may we continue feeding him the grain-free food?

Daisy Responds: A marketing gimmick, not a veterinary nutritionist’s recommendation, gave rise to the grain-free diet craze a few years ago. Tragically, veterinarians now realize that this fad diet can be deadly.

Veterinary cardiologists associate grain-free diets with a potentially fatal heart condition called dilated cardiomyopathy. DCM is inherited in some breeds, but after grain-free diets gained popularity, the disease became common in dogs not predisposed to it.

These cases of DCM-induced heart failure developed after dogs ate home-cooked diets or grain-free diets formulated primarily by small, boutique manufacturers and not tested in dogs.

Breck’s meat-based diet doesn’t protect him from DCM but actually increases his risk. Moreover, his unbalanced diet may cause additional problems.

For example, meat is high in phosphorus, so high-protein diets contain an abundance of this nutrient. Studies in pets show that excessive phosphorus increases the risk of chronic kidney disease.

Furthermore, if by “meat” you mean you are feeding Breck skeletal muscle, rather than organ meats, he is missing out on important nutrients. For instance, muscle meat is deficient in the amino acid taurine, and taurine deficiency causes DCM in dogs.

Talk with your veterinarian about transitioning Breck to a large, reputable company’s diet that contains grain. If you feel you must supplement this, be sure the additional food constitutes no more than 10 percent of his caloric intake so you don’t significantly unbalance his diet.