Common Myths About Pet Nutrition That Persist Despite the Evidence

The idea that grains are harmful to dogs took hold largely through marketing, not science. Dogs produce amylase — the enzyme needed to break down starch — and have done so across thousands of years of co-evolution with humans. Grains like brown rice, oats, and barley provide digestible carbohydrates, fiber, and nutrients.

More critically, the U.S. Food and Drug Administration (FDA) has investigated a potential link between grain-free diets — particularly those high in legumes such as peas and lentils — and DCM in dogs. While the science is still evolving, veterinary cardiologists and nutritionists have urged caution, especially for breeds already predisposed to heart disease. Unless your dog has a diagnosed grain allergy (which is rare), there is no evidence-based reason to choose grain-free.

The appeal of raw feeding is understandable: it feels closer to what animals ate before domestication. But "natural" does not automatically mean "safe" or "nutritionally complete." The American Veterinary Medical Association (AVMA) discourages feeding raw or undercooked animal-source proteins because of the risks they pose.

Studies have found that raw pet food samples frequently test positive for dangerous pathogens. Pets fed raw diets can shed these bacteria in their feces, creating a contamination risk — particularly for young children, elderly family members, and immunocompromised individuals in the household. Additionally, many homemade raw diets are nutritionally imbalanced unless carefully formulated by a veterinary nutritionist. If you have questions about pet-related health considerations in your household, our article on children and pet allergies explores related family safety topics.

Unlike dogs, who are omnivores, cats lack key metabolic pathways that would allow them to synthesize essential nutrients from plant matter. Taurine, for example, is found almost exclusively in animal tissue. A taurine deficiency in cats leads to serious conditions including retinal degeneration (blindness) and dilated cardiomyopathy.

No amount of careful planning can override feline biology. A cat fed a plant-based diet — no matter how well-intentioned — faces genuine health risks over time. If you follow a plant-based diet yourself and want to understand the broader nutritional science, our piece on plant-based eating vs. omnivorous diets covers the human side of that question thoroughly. For your cat, however, animal-based protein is non-negotiable.

The word "byproduct" sounds alarming, but in pet food it refers to organ meats — liver, kidney, heart — that are nutrient-dense and commonly eaten by animals in the wild. These are not scraps or waste; they are legitimate nutritional ingredients.

High-quality commercial pet foods undergo feeding trials and nutritional analysis to ensure they meet established standards. The AAFCO nutrient profiles define minimum and maximum levels of essential nutrients for different life stages. A food labeled "complete and balanced" has been verified against those benchmarks. That said, not all commercial foods are equally formulated, which is why reading labels and consulting your vet matters — but the category as a whole is not the nutritional wasteland the myth suggests.

Human nutritional thinking — where variety signals a balanced diet — doesn't translate directly to pet care. Dogs and cats have digestive systems adapted to a consistent diet. Frequent changes can disrupt the gut microbiome and cause vomiting or diarrhea, particularly in sensitive animals.

If you do need to switch foods — due to a life stage change, a health condition, or a product discontinuation — veterinarians recommend a gradual transition over seven to ten days, slowly mixing in the new food. Variety for its own sake, however, is not a veterinary recommendation. Consistency in a nutritionally complete food is a solid foundation for most healthy pets.