Common Myths About Dog Nutrition That Vets Still Hear

The idea that grains are fillers or allergens took hold partly through marketing and partly through the (incorrect) assumption that dogs evolved as pure carnivores. Dogs are actually omnivores with a digestive system well adapted to processing starches. Grains like rice, oats, and barley provide digestible carbohydrates, fiber, and nutrients. True grain allergies exist in dogs but are relatively uncommon — protein sources like beef and chicken are more frequent allergens. The FDA investigation into DCM and grain-free diets is ongoing, and causation has not been definitively established, but many veterinary cardiologists advise caution. If you suspect a grain sensitivity, work with your vet to confirm it before switching diets.

The appeal of raw feeding is understandable: less processing feels closer to nature. However, dogs' ancestral diets and modern raw diets are not the same thing, and "natural" does not equal "safe." Studies have found pathogenic bacteria in commercially prepared raw dog food at rates that concern public health and veterinary authorities, including the FDA and the American Veterinary Medical Association (AVMA). Dogs can shed these pathogens in their stool even when they appear healthy, creating risk in households with young children, elderly individuals, or immunocompromised people. Nutritional imbalances are also common in homemade raw diets. For a detailed breakdown of the trade-offs, see raw diet vs. commercial dog food.

Some foods that are entirely safe for humans are genuinely dangerous for dogs. Grapes and raisins can cause acute kidney failure. Onions and garlic damage red blood cells. Xylitol, an artificial sweetener found in many products including some peanut butters and chewing gum, can cause life-threatening drops in blood sugar. Even non-toxic scraps — fatty meat trimmings, bread, pasta — add calories without adding nutritional balance, and overfeeding is one of the most common preventable health problems in pet dogs. If you do give your dog human food, stick to small amounts of dog-safe options like plain cooked chicken, carrots, or blueberries, and account for the calories. Common avoidable dog care errors covers this in more depth.

Protein quality matters, but protein quantity alone does not define a diet's quality. A food with a very high protein percentage may still be nutritionally incomplete if it lacks adequate vitamins, minerals, or fiber. Carbohydrates, meanwhile, are not inherently harmful. Complex carbohydrates from whole grains or vegetables provide readily available energy and support a healthy gut microbiome. Dogs also produce the enzyme amylase in their intestines specifically for digesting starch — a key evolutionary adaptation that distinguishes them from wolves. The "all meat, no carbs" framing often comes from trends in human nutrition being applied to dogs without the supporting evidence.

Food manufacturers can engineer high palatability through fat content, flavor enhancers, and texture — none of which guarantee nutritional quality. A dog's willingness to eat something is not a reliable signal that the food meets their needs. This is especially relevant for homemade diets, which studies consistently show are frequently deficient in key nutrients like calcium, zinc, or certain vitamins when not formulated by a veterinary nutritionist. Excitement at mealtime is a poor proxy for health assessment. Regular veterinary check-ups, including weight monitoring and periodic bloodwork, give a much more accurate picture of whether your dog's diet is actually serving them well.