Should Boxers Eat Grain-Free Food?

Confusion surrounds the topic of grain-free dog food, which used to be associated with higher quality products but which more recently came under investigation by the FDA for a potential link with the heart condition dilated cardiomyopathy (DCM).

Boxer owners are understandably concerned about this, given DCM — enlargement of the heart that can be fatal — is a disease Boxers are prone to.

The question of whether Boxers should eat grain-free diets has a complicated answer.

If you want to cut to the chase:

Boxers should not eat grain-free dog food, but nor is grain-containing kibble an optimal diet for the breed.

The healthiest diet for a Boxer is a fresh, species-appropriate one that sticks as closely as possible to what dogs have eaten throughout a million years of evolution prior to domestication.

In other words, forget the highly-processed packaged foods and provide your Boxer with his natural diet: raw meaty bones, muscle meat and organs.

I am not a vet. This post is for general informational and educational purposes only. I encourage readers to see my full disclaimer here.

Now for the long answer.

Are Grain-Free Diets Good For Boxers?

A grain-free diet is perfectly fine insofar as Boxers, like all dogs, have no biological requirement for grains.

The trouble is that grain-free dog foods typically replace cereal crops like wheat, corn and rice with other fillers that are equally unnatural for dogs, often legumes like peas and lentils.

These legumes are such rich sources of vegetarian protein that dog food manufacturers can then reduce the meat content of their products while still satisfying their minimum protein requirements — and more cheaply than if they did so with meat protein.

This lower meat content can lead to a deficiency of the amino acid taurine, which is only found in meat, not plants.

Taurine deficiency is one of the causes of DCM.

While much remains to be understood, it’s safe to say that Boxers shouldn’t eat grain-free diets that are high in legumes and low in meat content.

However, it would be a mistake to think that simply avoiding grain-free, legume-heavy dog foods fixes the problem.

Grain-containing dog foods have many of their own drawbacks.

For a comprehensive look at what Boxer owners should know about kibble, see: Should Boxers Eat Kibble?

Why Does Grain-Free Dog Food Exist?

Grain-free dog food is a trend that arose within pet food manufacturing over the past decade.

“Grain-free” came to be a mark of “quality” dog foods, because some of these products avoided cheap carbohydrate fillers and instead opted for more expensive meat ingredients.

However, many grain-free foods just replace the grains with legumes, resulting in no more meat and potentially less meat because of the ability to achieve minimum protein requirements using the legumes (which wasn’t possible with cereal grains).

The popularity of grain-free dog food is in part due concerns about “food allergies” or “sensitivities” in dogs.

Some vets and owners believe eliminating grains can resolve symptoms — although it’s possible that dogs diagnosed as “allergic to grain” are reacting not to the grains but to the molds and their toxins that are known to contaminate the feed-grade corn and wheat used in kibble.

The Link Between Grain-Free Food And Dilated Cardiomyopathy (DCM)

Since July 2018, the US Food and Drug Administration has been investigating a spike in cases of dilated cardiomyopathy, or DCM, found in pets eating certain commercially-manufactured foods, many of them labelled “grain-free” and containing peas, lentils or pulses (legume seeds) as main ingredients.

The uptick in reported cases of DCM was seen in breeds not usually associated with this disease.

Boxers made up only 11 of the 515 cases of canine DCM reported to the FDA in the five years from January 1 2014 to April 30 2019.

The FDA found 91 per cent of the dogs that developed DCM were eating a grain-free or what’s come to be known as a boutique, exotic, grain-free (BEG) diet.

93 per cent of those grain-free products contained peas or lentils or both.

The FDA named 16 brands of pet food that were linked to high numbers of DCM cases, including:

  • Acana
  • Taste of the Wild
  • Blue Buffalo, and
  • Orijen.

Since grains are not part of a natural canine diet, the link to DCM is not thought to be the absence of grain, but the presence of legumes, which are defined as plants with seeds encased in a pod.

The exact mechanism is unclear.

Something in peas and lentils may affect the bioavailability of taurine.

Or it could be much simpler: taurine deficiency could arise due to the replacement of taurine-rich animal proteins with plant proteins that are devoid of taurine.

Yet another possibility is that the problem is not even the absence of taurine, but a lack of other amino acids, cysteine and methionine, which dogs use to make taurine.

The FDA says “the potential association between diet and DCM in dogs is a complex scientific issue that may involve multiple factors”.

Whatever the truth of the matter, the issue has highlighted shortcomings in the regulation of commercially-manufactured dog food: the dogs that developed DCM were all eating AAFCO (Association of American Feed Control Officials) approved dog foods labelled as “complete and balanced”.

A review of the scientific literature, published in June 2020, made the point that there are documented causes of DCM other than diet and concluded that the existing research does not support a speculated link between grain-free, legume-heavy diets and DCM.

But this paper has itself been heavily criticised for a flawed methodology that included cherry picking research to emphasize data that undermined a link between diet and DCM while ignoring evidence that corroborated the link, especially evidence that changing the diet has reversed DCM in dogs with the condition.

Critics also note that the authors of the literature review failed to disclose a conflict of interest: their employer, who funded the study, is an animal food consulting company that works with one of the pet food brands implicated by the FDA investigation.

Boxers And Dilated Cardiomyopathy (DCM)

Unlike the DCM seen in breeds like Golden Retrievers, the kind of DCM seen in Boxers is not related to taurine deficiency.

DCM in Boxers is attributed to a genetic predisposition.

This means that Boxers may be at no greater risk than any other breed of developing dietary-related DCM.

All the same, since any dog of any breed can develop DCM if the diet is inadequate, you will want to make sure your Boxer receives enough taurine.

How To Make Sure Your Boxer Gets Enough Taurine

Your Boxer will be receiving enough taurine if you are feeding a raw diet containing plenty of taurine-rich meats like:

  • poultry
  • heart
  • liver
  • fish, and
  • brain.

Ungulates (hooved animals) like beef, lamb and goat contain less taurine, as do eggs.

So, if your Boxer’s diet is based on beef, make sure you’re regularly including plenty of chicken and liver.

Do Boxers Need To Eat Any Grains At All?

Why do dog foods contain so much starch (carbohydrate) if dogs don’t need it?

Because it’s cheaper than meat.

And because the high-heat, pressurized extrusion process that pet food manufacturers use to make kibble only works with foods containing at least 30 per cent carbohydrate.

Hence the term “filler”.

In a natural setting, dogs may encounter grains and grasses in the stomach contents of prey or nibble on some greenery here and there, but as a proportion of the total diet this is minimal.

Dogs are “facultative” carnivores which means that meat is their primary food but they can sustain themselves on a secondary food (fruit, in the wild) when prey is scarce.

While dogs have no biological requirement for grains, there are signs that dogs’ bodies have begun adapting to the carbohydrate-heavy diets they’ve been eating since they began their association with humans.

Scientists comparing the dog and wolf genomes have found dogs have many more genes than wolves for the production of amylase, the digestive enzyme that breaks down starch.

The key to the dog’s survival has been adaptability.

Whether it’s a good idea for dogs to eat starchy diets or can do so without suffering health problems as a result is a separate question.

Related Reading:

Should Boxers Eat Large Breed Dog Food?


Grain-free diets are under a cloud as the FDA investigates a possible link with dilated cardiomyopathy.

Boxers, like all dogs, have no biological requirement for grains.

Grains figure in dry dog food because they’re cheap, readily available and boost the carbohydrate content necessary for the extrusion process used by kibble manufacturers.

The problems with grain-free diets are not well understood but may well relate to the ingredients those grains are replaced with, namely legumes.. or to the absence of enough meat.

A fresh, whole food diet consisting of plenty of raw meaty bones, muscle meat and offal will avoid both the problems associated with grain-free foods and those of grain-containing ones.


Canine heart disease has spiked — Here’s why, Dr Karen Shaw Becker, Mercola Healthy Pets, August 5 2019

Canine heart disease may relate to legumes, potatoes, American Veterinary Medical Association, March 13 2019

Diet, Dogs, and DCM, Mary Straus and Nancy Kerns, Whole Dog Journal, October 22 2019

FDA Investigation into Potential Link between Certain Diets and Canine Dilated Cardiomyopathy, Food and Drug Administration, June 27 2019

Paper downplaying risk to dogs of grain-free diets draws fire, Edie Lau, VIN News Service, July 9 2020

Review of canine dilated cardiomyopathy in the wake of diet-associated concerns, Sdyney R McCauley et al, Journal of Animal Science, June 2020

The Truth About Grain-Free Dog Foods And DCM, Dana Scott, Dogs Naturally Magazine, October 16, 2020