Myths About Pet Nutrition That Veterinary Science Has Largely Settled

The grain-free trend was largely driven by an assumption that wolves — dogs' wild ancestors — don't eat grains, so domestic dogs shouldn't either. But domestic dogs have evolved over thousands of years and digest starches quite differently from wolves. Grains such as rice, oats, and barley provide digestible carbohydrates, fiber, and micronutrients. The U.S. Food and Drug Administration (FDA) has investigated a possible link between grain-free, legume-heavy diets and DCM in dogs, prompting ongoing research. Unless your dog has a diagnosed grain allergy — which is relatively rare — there is no established nutritional reason to avoid grains. Discuss any diet change with your vet before making the switch.

The appeal of raw feeding is understandable — less processing, more "whole" ingredients. But veterinary and public health organizations, including the American Veterinary Medical Association (AVMA), have raised concerns about raw diets because raw meat can harbor Salmonella, Listeria, and other pathogens that can affect both pets and the people who handle their food. Additionally, many home-prepared and commercial raw diets have been found to be nutritionally incomplete — lacking critical vitamins and minerals. If raw feeding is something you want to explore, a board-certified veterinary nutritionist can help you build a diet that is both safe and complete. See our companion piece on raw diet vs. commercial kibble for a fuller breakdown.

Unlike dogs (and humans), cats cannot produce adequate amounts of taurine, arachidonic acid, or preformed vitamin A from plant sources. Taurine deficiency alone can cause blindness and heart failure in cats. While there are commercial vegan cat foods that attempt to supplement these nutrients synthetically, the long-term adequacy of such diets is not well established, and veterinary nutritionists generally recommend against them unless there is a compelling medical reason. If a plant-based diet is a priority for you, this is a conversation to have directly with a veterinary nutritionist who can monitor your cat's health closely over time.

Some human foods are outright dangerous for pets: grapes, raisins, onions, garlic, xylitol (a sweetener found in many products), macadamia nuts, and chocolate are well-documented hazards. Beyond toxicity, even safe foods fed regularly as extras can throw off the caloric and nutrient ratios your pet's primary food is designed to deliver. High-fat table foods are a common contributor to pancreatitis in dogs. If you want to offer occasional treats, plain cooked lean meat or certain vegetables like carrots are generally low-risk — but portion size matters. For more on how overfeeding accumulates, see why pets gain weight.

Terms like "natural," "holistic," and "human-grade" on pet food packaging are used primarily for marketing purposes. AAFCO has a narrow definition of "natural" (essentially, no synthetic additives), but "holistic" and "human-grade" have no regulated meaning in pet food labeling. A food can carry these labels and still be nutritionally incomplete. The most meaningful thing to look for on a pet food label is an AAFCO nutritional adequacy statement — specifically, that the food has been tested by feeding trials or formulated to meet AAFCO nutrient profiles for your pet's life stage.