How Americans Decided Dogs Can’t Eat Grains

A new warning about dog food underscores a problem with certain diets that goes beyond pets.

A pug climbs on a table to sniff food.
Klaus Vedfeldt / Getty

Although she is very special to me, Midge, my three-year-old rescue Chihuahua, is not all that special in general. She’s the average weight for her size. She has no known medical problems, besides anxiety, which is probably rational given that she’s eight inches tall. Nothing I’ve ever fed her has seemed to irritate her tiny little tummy.

Nevertheless, I feed her only grain-free dog food. The kind I give her costs about $100 a month (for a 12-pound dog!), and it’s made of an organic, grass-fed, non-GMO mix of beef, organ meat, and bone, all of which is processed with spinach and blueberry and freeze-dried into a patty the size of a Popeye’s biscuit. Twice a day, I break up one and a half patties into her bowl by hand, often immediately before I go pick up a bagel for breakfast or meet friends for hot wings and cheap beer.

Grain-free dog food used to be a relative rarity, reserved for pets with certain dietary issues. But in the past decade, millions of dog owners have shied away from conventional foods that include ingredients such as rice or oats, out of concern that grains might be bad for dogs’ health. Now grain-free options constitute almost half of the dog-food market in the United States. Over the same period, gluten-free and low-carbohydrate diets also exploded in popularity for humans.

Leaving grains out of your dog’s diet, however, might be a far greater health risk than keeping them in. According to a warning from the Food and Drug Administration released last week, grain-free food might be giving dogs a life-threatening heart problem called dilated cardiomyopathy, or DCM. The science is still preliminary, and it’s based on a potential association between diet and heart disease in fewer than 600 dogs. But as this link continues to be investigated, these new concerns tell a cautionary tale about how contemporary American culture approaches health and nutrition—and not just for pet owners.

Contrary to the broad cultural embrace of grain-free diets in recent years, science has offered little evidence to support their adoption among America’s canine companions. “It’s extremely, extremely rare for dogs to have a grain sensitivity,” says Lisa Lippman, the lead New York veterinarian for the in-home veterinary service Fuzzy Pet Health. “This misinformation is a battle we face almost every day in the clinic, and it’s something that’s definitely been a source of frustration for us since before [the FDA warning] even came out.”

Lippman says that more dog-food brands started making grain-free options, simply because consumers demanded them. The New York Times traces the shift away from grain back to a headline-grabbing recall of tainted Chinese kibble in 2007, in which wheat gluten from a particular supplier was contaminated with melamine. That was enough to help fears about wheat, and then grains more generally, spiral out of control.

Myths about dogs and grain spread in much the same way that trends for things such as celery juice or paleo diets have spread for humans: Online, through a mix of self-appointed nutrition experts and mostly well-meaning social-media users who fail to parse the origins of information that’s presented as factual and scientific. And it’s not just the method through which people find these beliefs that’s similar; it’s many of the beliefs themselves. “People will anthropomorphize or project onto their pets whatever they think they need to eat themselves,” Lippman explains.

Humans, in general, aren’t great at conceptualizing what science says about their diets. Although fewer than 1 percent of Americans have celiac disease, a damaging autoimmune response to gluten, diets that avoid gluten-containing grains such as wheat and barley as a health measure became very popular in the early 2010s.* In 2012, as much as 30 percent of the United States population was trying to reduce their gluten intake, despite scant scientific evidence that gluten is harmful to most people. During the same period, Americans were also becoming suspicious of the health implications of corn’s many uses in modern food processing. In addition to being common in the American diet, wheat, barley, and corn form the base of many conventional dog foods.

Christopher Lea, a veterinary-medicine professor and a director of the Auburn University Veterinary Clinic, says that once people think they’re doing right by their pets, even a veterinarian can have a hard time persuading them to use a type of food they’re confident is unhealthy. “One thing you’ll learn is that people are very passionate about their pets’ diets,” Lea says. Sometimes, controlling a dog’s diet can turn into an opportunity to exercise a person’s own food anxieties: You may crave white bread or soda made with corn syrup, but it’s relatively easy to enforce a strict diet on a dog that can’t go buy its own kibble.

Just as it does with human diets, misinformation can turn into popular belief with disconcerting ease. People with the resources to buy specialized food and health products, both for their pets and themselves, create a demand that brands fill with expensive specialty goods. That high-end market positioning tends to be self-reinforcing in America, where expense and rarity are seen as signifiers of high quality.

After a while, most consumers won’t know the origin of the belief that’s motivating their purchases—in this case, that dogs shouldn’t eat any grains. Instead, they see that all the fanciest dog food is grain-free, and that the people they know who are really into their pets buy that food, and the righteous choice feels clear, if they can afford it. Before I heard about the FDA warning, I had never thought much about why I feel like I have to feed my 12-pound Chihuahua $100-a-month grain-free food, other than that it seems fancy, and Midge is my fancy girl.

The FDA stopped short of recommending that consumers switch their pets off the grain-free foods. “Because we have not yet determined the nature of this potential link [between grain-free dog food and DCM], we continue to encourage consumers to work closely with their veterinarians, who may consult a board-certified veterinary nutritionist, to select the best diet for their pets’ needs,” said a spokesperson for the FDA in an emailed statement.

Lippman agrees that the FDA findings are still early and inconclusive. “We don’t know if it’s the fact that the diets are grain free, or if it’s the fact that in these grain-free diets, they seem to substitute for the grains with a lot of legumes, like lentils and peas” that might be causing the heart problems, she explains. Still, she thinks it’s better to be safe. “Even though I think it’s uncommon and unlikely to happen to your dog, it’s so unnecessary to be feeding grain-free,” she cautions. “DCM is just not a disease you want to mess with, and as a pet parent, to think that you could have caused it, even inadvertently, is really devastating.”

Lea also sees no reason to stick with grain-free food. “I don’t feed grain-free diets to my pets, and I’d certainly be cautious after what I’ve read and what I’ve seen from our cardiologist,” he says. But he worries that even scientifically demonstrated risk may not be enough to sway some people. “I’ve been doing this for 20 years, and some people just have very passionate feelings about grains.”

* This article previously mischaracterized how the body responds to gluten in celiac disease.