Common Pet Nutrition Myths That Persist Despite the Evidence

Domestic dogs have evolved alongside humans for thousands of years and possess genetic adaptations — including additional copies of the amylase gene — that allow them to digest starch efficiently. Grains such as rice, oats, and barley provide digestible carbohydrates, fiber, and micronutrients. The U.S. Food and Drug Administration (FDA) has investigated a potential link between grain-free diets (particularly those high in legumes and potatoes) and DCM, a potentially fatal heart condition. While the mechanism is still being studied, veterinary cardiologists and nutritionists have broadly advised caution with these diets, especially for breeds already predisposed to DCM.

The American Veterinary Medical Association (AVMA) and the Centers for Disease Control and Prevention (CDC) have both raised concerns about raw meat diets due to the documented risk of Salmonella, Listeria, E. coli, and other pathogens — not just for pets but for the humans who handle the food or come into contact with the pet's saliva and feces. Beyond safety, homemade raw diets that haven't been formulated by a credentialed nutritionist frequently show calcium-phosphorus imbalances and deficiencies in vitamins and trace minerals. The 'wild diet' comparison also overlooks that wild animals have shorter lifespans and suffer significant disease burdens that their diets do not protect against.

Pet food labeling rules require ingredients to be listed in descending order by weight before processing. Because fresh meat contains a high percentage of water, it weighs more in its raw state than after cooking — which means "chicken" may appear first on a label, but the actual dry-weight contribution of chicken meal or other ingredients further down the list can be substantial. A more reliable approach is to look at the guaranteed analysis panel (showing protein, fat, fiber, and moisture percentages) alongside the ingredient list, and to verify that the food meets AAFCO nutritional standards for your pet's life stage. Our label-reading guide walks through this in more detail.

Unlike dogs, cats cannot synthesize adequate amounts of taurine (an amino acid), arachidonic acid (an omega-6 fatty acid), or vitamin A from plant precursors. These must be present in the diet in preformed amounts. Dog food is not formulated to deliver these nutrients at the levels cats require. Feeding a cat dog food long-term can result in serious deficiencies, including taurine-deficiency dilated cardiomyopathy and vision problems. Conversely, cat food is generally too calorie-dense and protein-rich to serve as a regular diet for dogs. Species-appropriate food — verified by AAFCO statements — is the baseline for both.

Grapes, raisins, onions, garlic, xylitol (found in many sugar-free products), macadamia nuts, and chocolate are among the foods that can cause serious harm or death in dogs and cats. Even foods that are not toxic can disrupt the nutritional balance of a complete commercial diet if added in significant quantities. Some vegetables — plain cooked carrots or green beans, for example — are generally considered safe in small amounts as occasional treats, but they should not substitute for a balanced diet. Any intentional dietary supplementation should be discussed with a veterinarian, particularly for pets with existing health conditions. See what it means when a pet stops eating if appetite changes follow a diet shift.