Short answer: for most dogs, grain-free food has no proven health advantage, and grain allergies are uncommon. The main concern is heart disease: in the FDA’s investigation of diet-associated dilated cardiomyopathy (DCM), more than 90% of the products named in reports were grain-free and 93% contained peas and/or lentils. The FDA hasn’t proven that these diets cause DCM, but AAHA’s 2021 nutrition guidelines call avoiding grain-free and legume-heavy diets “the most conservative approach.”
Grain-free dog food became hugely popular over the past decade, largely on the premise that grains are an unnecessary or even harmful filler — but the actual evidence is more nuanced than the marketing behind the trend.
Why Did Grain-Free Food Become Popular?
The rise of grain-free diets was driven partly by comparisons to a dog’s wild ancestral diet and partly by the assumption that grains are simply cheap fillers with little nutritional value. Neither holds up well. Veterinary nutritionist Lisa Freeman of Tufts wrote on the school’s Petfoodology blog that grains “do not contribute to any health problems” and are used in pet food “as a nutritious source of protein, vitamins, and minerals,” and that there’s no evidence exotic ingredients are more natural or healthier than typical ones.
What Is the Case For Grain-Free Food?
- A confirmed allergy to a specific grain. It happens: wheat was an offending allergen in 13% of food-allergic dogs in one review. A grain-free food (or any food without that grain) is appropriate for those dogs.
- Owner preference. A grain-free food can still meet AAFCO’s complete-and-balanced standard. The FDA’s reports pointed to particular formulations, especially legume-heavy ones, and the agency says it has no definitive information that these diets are inherently unsafe.
What Is the Case Against Grain-Free Food?
- The DCM investigation: the FDA identified a potential association between certain grain-free diets — especially those high in peas, lentils, and other legumes — and dilated cardiomyopathy, a serious and sometimes fatal heart condition, in dog breeds without a typical genetic predisposition to it
- Grain allergies are less common than marketing implies: beef, dairy and chicken are more frequent causes of diagnosed food allergies in dogs than any grain
- No proven nutritional advantage for most dogs: grains are a useful source of protein, vitamins and minerals, and a dog without a grain allergy gains nothing established from avoiding them
- Cost: grain-free and boutique formulas are frequently more expensive without a demonstrated benefit for the average healthy dog
What Did the FDA Actually Find About Grain-Free Food and DCM?
DCM is a disease of the heart muscle that makes the heart pump weakly and enlarge. It has long been recognized as a genetic condition in large and giant breeds such as the Doberman Pinscher, Great Dane and Irish Wolfhound. What caught cardiologists’ attention was DCM appearing in breeds not usually affected, often in dogs eating boutique, grain-free or exotic-ingredient diets.
| Date | What the FDA reported |
|---|---|
| July 2018 | Announced it was investigating a potential link between certain diets and DCM |
| June 2019 | 524 DCM reports received from January 2014 to April 2019 (515 dogs, 9 cats); more than 90% of reported products were grain-free and 93% contained peas and/or lentils |
| November 2022 | 1,382 dog DCM reports received between January 2014 and November 2022 |
| December 2022 | No further public updates planned “until there is meaningful new scientific information to share” |
The FDA’s questions-and-answers page is careful about what this does and doesn’t mean. Report numbers alone “do not supply sufficient data to establish a causal relationship,” the agency says; non-hereditary DCM is a complex condition that may involve genetics, underlying disease and diet; and legumes “have been used in pet foods for many years, with no evidence to indicate they are inherently dangerous.” The FDA has not requested recalls, stating it has “no definitive information indicating that the diets are inherently unsafe and need to be removed from the market.”
Researchers are still working out what is going on. Tufts’ Freeman describes what may be two separate problems: some affected dogs had low taurine and improved with supplementation, while others had normal taurine, pointing to a still-unknown factor.
Which Dogs Should Be Most Careful?
- Breeds prone to genetic DCM, such as the Doberman, Great Dane and Irish Wolfhound. See our Doberman diet guide for how this shapes feeding.
- Breeds linked to taurine-related DCM. AAHA lists Golden Retrievers and Newfoundlands among predisposed breeds, and Tufts notes Cocker Spaniels have improved with taurine supplementation.
- Any dog with signs of heart trouble. The FDA lists decreased energy, cough, difficulty breathing and episodes of collapse. Heart disease becomes more common with age, as our article on heart disease in senior dogs explains.
What Does This Mean in Practice?
For the majority of healthy dogs, there’s no established nutritional need to avoid grains. AAHA’s 2021 Nutrition and Weight Management Guidelines put it this way: “Given currently available evidence, the most conservative approach is to avoid feeding grain-free diets or diets high in legumes,” while encouraging owners to weigh the pros and cons with their vet because the evidence is still evolving. This doesn’t mean every grain-free food is dangerous — but it does mean “grain-free” shouldn’t be treated as automatically the healthier or more natural choice.
How Do You Decide What’s Right for Your Dog?
Talk to your vet, particularly if your dog is currently on a grain-free diet or you’re considering switching. A vet can help weigh your specific dog’s health history, any diagnosed sensitivities, and the current research against marketing claims — a more reliable approach than deciding based on packaging alone. A few practical steps:
- Read the ingredient list. Note whether peas, lentils, chickpeas or other legumes, or potatoes, appear near the top. Our guide to reading a dog food label explains how ingredient order works.
- Look at the manufacturer, not just the claims. Our guide to judging dog food brands covers questions worth asking, such as who formulates the food.
- If your dog has skin or stomach problems, test before you blame grain. A vet-supervised elimination trial is the way to identify a food allergy; our guide to food for sensitive stomachs compares the diet types used.
- Switch gradually. AAHA’s weight management guidelines suggest introducing a new food over at least a week.
- Watch for heart signs and report them promptly, whatever your dog eats.
This article is for informational purposes only and does not replace guidance from your veterinarian.
Sources
- FDA — FDA Investigation into Potential Link between Certain Diets and Canine Dilated Cardiomyopathy, updated December 2022
- FDA — Questions & Answers: FDA’s Work on Potential Causes of Non-Hereditary DCM in Dogs, August 2024
- AAHA — 2021 AAHA Nutrition and Weight Management Guidelines: Diet-associated Dilated Cardiomyopathy, June 2021
- Tufts Cummings School, Petfoodology — A broken heart: Risk of heart disease in boutique or grain-free diets and exotic ingredients, June 2018
- Mueller RS, Olivry T, Prélaud P — Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats, BMC Veterinary Research, 2016
- AAHA — 2014 AAHA Weight Management Guidelines for Dogs and Cats
