Hoax or Real, Is Grain-Free Cat Food Bad for Cats?

Pet store aisles are awash with grain free pet food, mimicking the same trend seen in human diets. But is grain free food bad for cats?

Grains are more than just ‘fillers.’ Grains are a good source of fiber, vitamins, minerals, and essential fatty acids. Some grains also provide easily digestible protein.
– Lynn Buzhardt, DVM

Grain free cat food is cat food without corn, wheat, barley, rice, or oats. And yes, grain free cat food is bad for some cats. Like cats who are overweight or who have diabetes. Why? Because many grain free cat food contains peas and peas have lectins and phytates which cause all sorts of health issues (more on that below).

In this article we bust the myths around grain free cat food and dig deep into the science that explains if this food is right for your cat’s nutritional needs.

Why is grain free cat food so controversial?

It’s been impossible to ignore the headlines that grain free pet food is linked to rising rates of heart disease in pets. Are there really risks for fatal heart disease if your cat eats grain free?

It all started with dogs. In 2018 the FDA began investigating a potential link between canine heart disease and grain free dog food. Soon after, the FDA warned that grain free cat food could also be linked to dilated cardiomyopathy, also called DCM.

What is heart disease in cats?

The AVMA says that heart disease affects 1 out of 10 cats worldwide. They define feline heart disease as either, congenital heart disease, or acquired heart disease.

Congenital heart disease

Congenital heart disease is a condition your cat is born with. This is also known as a “genetic abnormality.” Certain cat breeds, like Maine Coons have higher rates of congenital heart disease.

Acquired heart disease

Your cat develops this type of heart disease over time. The possible connection between dilated cardiomyopathy and grain free food is an acquired heart disease.

Does grain free cat food cause heart problems?

Unraveling the connection between grain free cat food and heart disease is tricky. Mainly because there’s so little data on diet-linked DCM in cats. Here’s an example.

Since 2014, the FDA has been gathering data related to heart disease and grain free pet food. Data collected from January 2014 through July 2020 report these numbers as 1,100 dogs and 20 cats with diet-related DCM. Those numbers alone are shockingly different.

As a whole, the research and data for feline dilated cardiomyopathy and grain free cat food are scant.

gluten free cat food

For one, Veterinarian Lynn Buzhardt, DVM, proposes a different theory for diet-related feline DCM. Buzhardt says cats are most likely to develop heart problems and heart disease from taurine deficiencies.

If cats are missing this essential amino acid they could suffer from the DCM associated with grain-free cat food.

Some exciting new findings shed more light on the impacts of grain free pet food and health. A January 2021 report from the FDA and American Veterinary Medical Association (AVMA) claims specific ingredients may be the culprit, not grain free pet food as a whole.

Dr. Steven M. Solomon, director of the FDA Center for Veterinary Medicine, says, “a pattern [has] emerged. Dogs in [DCM] cases submitted to FDA were reported to have consumed diets containing high proportions of dried legume seeds, including peas, chickpeas, and lentils.”

But, again, this data is skewed by species. The FDA and AVMA’s data includes 55 times more dogs than cats.

What is the healthiest grain free cat food?

The healthiest grain free cat foods are the ones that prioritize meats and animal protein ingredients.

Cats need to eat high protein diets rich in meat in animal protein to not only thrive but to function, period.

Wet grain free cat food tends to be a better choice than dry food options. Crunchy kibble uses starches to keep the dry pieces of food together. This means that grain free dry cat food uses more carb-heavy ingredients like ground potatoes, lentils, and peas.

Wet grain free cat food often contains higher protein and less vegetable and fruit ingredients which is ideal for your kitty’s health and wellness.

The main thing to look out for is the Association of American Feed Control Official (AAFCO) stamp of approval. The AAFCO stamp on a cat food label means the food has met the nutritional standards set forth by AAFCO. The next thing to be aware of are grain free cat foods that heavily rely on vegetable ingredients—more on that below.

Choosing a Healthy Cat Food

The problem with grain free cat food

Some veterinarians argue grain free cat food is more problematic than conventional cat food. They point out that grain free food has become more of a designer cat food diet than anything. Pet food companies aggressively market grain free cat food with tactics like overpromising unregulated health benefits, banking on pet parents believing grains are all bad.

Are all grains bad?

It’s not the lack of grains that are the problem here. The issue is the ingredients used in place of the grains. Instead of oats, barley, and rice, grain free cat food typically uses peas, beans, and vegetables like white potatoes and sweet potatoes.

Just as you could argue that cats don’t eat oats and rice in the wild, the same can be said for potatoes, lentils, cranberries and other grain free staples.

These ingredients can wreak as much havoc on your kitty’s gastrointestinal tract as grains. Cats’ bodies aren’t built to digest high amounts of plant matter. They thrive on diets that mimic what they’d eat in the wild. Mainly meat and animal proteins.

The problem with peas

Let’s start with one of the most controversial ingredients in grain free cat food: peas. This ingredient is a staple in dry grain free cat food, where it acts as a starch to help the crunchy kibble hold its shape.

Peas are notoriously hard for cats to digest and can cause tummy troubles like diarrhea. But that’s not all. Peas and other legumes can impact your kitty’s health on a larger scale.

According to Dr. Karen Becker, DVM, peas, and legumes contain lectins and phytates.


Lectins are sticky-sugar binding molecules that could build up inside your kitty’s small intestine. Lectin harms the healthy bacteria in your cat’s gut known as microflora. And it eats away at their intestinal lining causing severe gastrointestinal discomfort. It could even lead to chronic stomach illnesses like leaky gut syndrome.


Phytates are impossible for cats to break down. Because of that, they bind to nutrients like calcium, magnesium, iron, and zinc. This leeches the minerals out from your kitty’s body, seriously hurting their ability to absorb the nutrients they need. Yikes.


Does my cat need a grain free diet?

The only cats who need a grain free diet are ones with grain food allergies or intolerances.

The reality is most cats don’t require a grain free diet. It’s more common for cats to have chicken, beef, fish, or dairy food allergies.

Veterinarian Dr. Donna Solomon, DVM, cautions that while some cats and dogs “benefit from grain-free diets [it’s] definitely not to the magnitude the pet food industry would lead you to believe.”

Myths about grain free cat food

If you buy into any (or all) of these myths, we don’t blame you! Grain free = healthier has been hammered into the collective consciousness of cat parents to the point where it feels like it’s been right all along.

But here’s the thing. Decades before grain free cat food became a buzzword, our cats were living healthy lives that included grains.

So let’s bust those “grain free is healthier” myths.

Myth one: grain free cat food is good for weight loss

If you’re feeding your cat grain free food for weight loss or weight management, you’re better off looking elsewhere.

A large grain free cat food study conducted by Tufts University Cummings Veterinary Medical Center sheds found that grain free cat food often contains the same calories and more carbs than traditional cat food.

Myth two: grain free cat food is low carb

The idea that grain free cat food is lower in carbohydrates is untrue. The same study found that grain free usually means more carbs than regular cat food.

Considering that the Association for Pet Obesity Prevention reports 60% of cats in the US are overweight or obese, this is a problem.

Myth three: grain free cat food is low calorie and low fat

The Tuft’s study also found that grain free cat foods are more likely to use species-inappropriate, hard to digest ingredients like papaya, zucchini, and avocado.

The high amounts of glucose from veggies in grain free cat food like potatoes could lead to high blood sugar, potentially causing life-threatening complications.

designer cat food diets

What cats should avoid grain free diets?

Grain-free diets are not appropriate for all cats. Some cats should steer clear of grain free diets altogether.

Holistic veterinarian Dr. Jean Hofve, DVM, warns that grain free food isn’t the best option for overweight, obese, or inactive cats. This is because most grain free foods may be higher in carbs, calories, and fat. Diabetic cats should also avoid grain free diets.

Cats who are prone to hairballs and constipation also benefit from higher fiber conventional cat food. Fiber, something that many grain free diets don’t have enough of, is a powerful tool in combating both of these GI-related issues.

What’s the difference between grain free and gluten free diets?

Grain free doesn’t = gluten free. Some grains are naturally gluten free. The Celiac Disease Foundation notes that corn, rice, millet, and quinoa are all gluten free grains. Oats, a common ingredient in cat food, are also a grain that’s gluten free.

Simply put, gluten free cat food only omit wheat, barley, and rye.

So, is grain free cat food bad for cats?

No one diet is suitable for all cats or bad for all cats. Grain free cat food is no exception. Although successful marketing makes it seem as though grains cause a host of problems in our feline friends, science begs to differ.

Unlike what many grain free companies would have you believe, grains are nutritious. Veterinarian Lynn Buzhardt, DVM, says, “grains are more than just ‘fillers.’ Grains are a good source of fiber, vitamins, minerals, and essential fatty acids. Some grains also provide easily digestible protein.”

The most common grains in cat food like oats and rice, are a good source of fiber, zinc, and Vitamins B and E, among other nutrients.

Buzhardt continues, “Even though cats are historically carnivores, their digestive tracts are pretty efficient at processing carbohydrates from grain.”

Ultimately, Buzhardt puts it this way, “There is no conclusive evidence that whole grains are harmful to the general cat population.”

The bottom line on grain free cat food

There’s no solid evidence that grains are harmful to cats. Many grain free cat foods could actually be problematic for your kitty! They’re often loaded with vegetables, carbs, and ingredients like peas and legumes that could block your kitty’s ability to absorb essential nutrients.

The next time you’re stranded in the cat food aisle and overwhelmed by the sheer magnitude of choices, a better question than ‘Is grain free food bad for cats?’ is to ask yourself, ‘What is the most balanced and nutritionally complete food for my cat?’


Victoria Tomis