The Truth Behind Common Pet Nutrition Myths

The grain-free trend was driven largely by an analogy to low-carb human diets and the assumption that dogs evolved to eat only meat. In reality, dogs are omnivores with a demonstrated ability to digest starches — a trait that likely developed alongside thousands of years of coexistence with humans eating grain-based diets.

The U.S. Food and Drug Administration (FDA) investigated a potential association between grain-free diets high in legumes (peas, lentils, chickpeas) and dilated cardiomyopathy (DCM), a serious heart condition. While the investigation did not establish definitive causation, veterinary cardiologists have urged caution. Grains like rice, oats, and barley supply fiber, B vitamins, and energy — they are not empty fillers. Talk to your veterinarian before switching to a grain-free formula.

The appeal of raw feeding is understandable — it frames food as unprocessed and instinctual. However, major veterinary organizations, including the American Veterinary Medical Association (AVMA), discourage raw meat-based diets due to the risk of pathogens such as Salmonella, Listeria, and E. coli. These bacteria can sicken both pets and the people handling the food, including children, elderly individuals, and immunocompromised household members.

Homemade raw diets are also frequently nutritionally incomplete. Studies have found that many raw diet recipes — even those published in books — fail to meet AAFCO nutrient minimums for key minerals, vitamins, and fatty acids. For a balanced look at the trade-offs between feeding formats, see dry food, wet food, and raw diets.

Unlike dogs or humans, cats cannot synthesize several essential nutrients from plant precursors. Taurine, an amino acid critical for heart function and vision, is absent from plant foods; taurine deficiency causes irreversible retinal degeneration and DCM in cats. Similarly, cats cannot convert beta-carotene to vitamin A or convert linoleic acid to arachidonic acid efficiently — both must come from animal sources.

Feeding a cat a plant-based diet, even with good intentions, risks creating serious and sometimes irreversible nutritional deficiencies. If you have ethical concerns about animal-sourced ingredients, the most responsible path is to discuss commercially formulated options with a board-certified veterinary nutritionist rather than eliminating animal protein entirely.

Ingredient lists are ordered by weight before processing — meaning fresh chicken, which is roughly 70% water, may appear first but contribute far less protein by dry weight than a meat meal listed lower down. "Chicken meal," for example, is a concentrated, dry protein source that can outweigh fresh chicken in actual protein delivery per gram.

This doesn't make any single format better or worse, but it does mean that scanning the first ingredient alone is an incomplete way to evaluate a food. The guaranteed analysis panel — which lists minimum crude protein and fat percentages — gives more actionable nutritional data. Our companion article on what pet food labels actually tell you walks through each section of a label in plain language.

Caloric density is easy to underestimate with scraps. A small cube of cheese or a piece of bread can represent 10–20% of a small dog's daily calorie needs. Over time, consistent extras contribute to weight gain, which is one of the most common and consequential health problems in companion animals. For more on the factors behind pet weight changes, see why pets gain weight and what's actually behind it.

Beyond calories, several common human foods are outright toxic to dogs and cats — including grapes, raisins, onions, garlic, xylitol (an artificial sweetener found in many products), and macadamia nuts. Even foods that aren't toxic may be high in salt, fat, or spices that stress a pet's digestive system. Treats of any kind, including scraps, ideally shouldn't exceed 10% of total daily caloric intake.