Key Takeaways
- Grain-free diets have been linked to a potential heart condition in dogs; consult your vet before switching.
- 'Natural' and 'holistic' on pet food labels carry little to no regulatory weight.
- By-products in pet food are not necessarily low-quality; some are nutrient-dense organ meats.
- Raw diets carry real bacterial contamination risks for both pets and the people handling the food.
- A food's ingredient order does not fully determine its nutritional quality or completeness.
Why Pet Food Marketing Runs Ahead of the Science
Walk down any pet store aisle and you'll encounter a cascade of claims: grain-free, ancestral diets, human-grade, holistic, raw-fed. These labels are designed to appeal to owners who genuinely want the best for their animals — and that instinct is good. The problem is that marketing language moves faster than peer-reviewed research, leaving pet owners making decisions based on assumptions rather than evidence.
Understanding which claims are regulated, which are loosely defined, and which have been actively questioned by veterinary researchers is one of the most practical things a new pet owner can do. For a deeper look at how specific label terms are — and aren't — defined, see our guide to pet food label terms.
Myth
Grain-free food is healthier for most dogs and cats.
Fact
There is no broad evidence that grain-free diets benefit pets without a diagnosed grain sensitivity, and they may carry cardiac risks for dogs.
Grains such as rice, oats, and barley are digestible energy sources that have been safely used in commercial pet food for decades. The idea that grains are harmful likely borrowed momentum from human low-carb diet trends. In reality, true grain allergies in pets are uncommon — proteins like beef and chicken are far more frequent allergens. More importantly, the FDA issued an ongoing investigation into a potential link between legume-heavy, grain-free diets and dilated cardiomyopathy (DCM) in dogs. Until the science is clearer, switching to grain-free without veterinary guidance is not recommended.
Myth
Meat by-products are filler ingredients and a sign of low quality.
Fact
Many by-products — including liver, kidney, and heart — are nutritionally dense organ meats that are standard in quality pet food.
The term "by-product" sounds unappetizing, but AAFCO defines meat by-products as the non-rendered, clean parts of slaughtered animals other than meat — including organ meats, which are highly nutritious. Liver, for example, is rich in vitamins A, B12, and iron. The actual quality of a by-product depends on the manufacturer's sourcing standards, not the word itself. Judging food quality solely on whether it avoids the word "by-product" can be misleading.
Myth
The first ingredient tells you everything about a food's quality.
Fact
Ingredient order reflects weight before cooking, not nutrient density after processing — a single ingredient's position is not a complete quality indicator.
Ingredients are listed by pre-cooking weight, which means a whole meat listed first may shrink significantly after moisture is removed during processing. Meanwhile, several grain or carbohydrate sources listed further down can collectively outweigh that first ingredient once combined. What matters more than ingredient order is whether the overall formulation meets AAFCO nutritional standards for your pet's life stage, and whether it was validated through feeding trials rather than just calculation.
Myth
Raw diets are more natural and therefore safer and more nutritious.
Fact
Raw diets carry documented risks of bacterial contamination for pets and humans, and nutritional completeness is not guaranteed.
Organizations including the American Veterinary Medical Association (AVMA) and the Centers for Disease Control and Prevention (CDC) have raised concerns about raw meat diets for pets, citing risks of pathogens such as Salmonella, Listeria, and E. coli — which can affect both animals and the people handling their food. "Natural" does not automatically mean safe or nutritionally complete. Ancestral diets in the wild also came with shorter lifespans and significant disease burden. If you're considering a raw diet, discuss it thoroughly with a veterinarian first.
Myth
"Holistic" and "natural" on a pet food label mean the product is regulated to a higher standard.
Fact
Neither term is legally defined or enforced by AAFCO or the FDA for pet food — they are essentially unregulated marketing words.
Unlike the term "organic," which has a defined regulatory framework in the U.S., "holistic" has no official legal definition in the context of pet food. "Natural" has a loose AAFCO guideline — generally meaning no artificial flavors, colors, or preservatives — but enforcement is inconsistent and the term does not speak to nutritional quality, sourcing standards, or safety. Seeing these words on a label should not, on their own, influence your purchasing decision.
What the Evidence Actually Supports
Veterinary nutrition is a legitimate specialty, and its guidance sometimes clashes with popular trends. The U.S. Food and Drug Administration (FDA) investigated a potential association between grain-free diets and dilated cardiomyopathy (DCM) — a serious heart condition — in dogs, beginning in 2018. While causation has not been definitively established, the inquiry remains open and many board-certified veterinary cardiologists advise caution.
Don't Switch Diets Without Veterinary Input
Abruptly changing your pet's food — especially to a trending diet like raw or grain-free — can cause digestive upset and, in some cases, longer-term health concerns. Any dietary change should be gradual (typically over 7–10 days) and ideally discussed with your veterinarian beforehand, particularly for puppies, kittens, senior pets, or animals with existing health conditions.
The most reliable indicator of a food's quality isn't its ingredient list or marketing buzzwords — it's whether the food meets the nutritional standards set by the Association of American Feed Control Officials (AAFCO) for your pet's life stage. Look for a statement confirming the food was formulated to meet AAFCO profiles or was tested through feeding trials. For a full breakdown of what those label details mean, our article on reading a pet food label walks you through it step by step.
~10%
Dogs with food allergies that react to grains
Veterinary dermatologists estimate that true grain sensitivities account for a small minority of food allergy cases in dogs; animal proteins are far more common triggers.
77+
Dog breeds reported in FDA's DCM investigation
The FDA's 2019 update on diet-associated DCM included reports spanning more than 77 dog breeds, with a notable proportion eating grain-free, legume-heavy diets.
First-time owners are also prone to a handful of broader nutritional missteps beyond food choice alone — things like overfeeding or misreading portion guides. Our companion piece on what new pet owners get wrong about nutrition covers those in detail. And if you're weighing kibble, wet food, or raw options more broadly, see our factual comparison of dry food, wet food, and raw diets.
This article is for general informational purposes only and does not constitute veterinary or medical advice. Always consult a licensed veterinarian before making significant changes to your pet's diet.
