what are the disadvantages of grain free dog food

What are the Disadvantages of Grain Free Dog Food?

Explore the disadvantages of grain-free dog food with insights from an experienced veterinarian.

In recent years, the trend of feeding dogs grain-free diets has surged in popularity among pet owners, driven by the belief that these diets are closer to a dog’s natural ancestral diet and can solve various health issues attributed to grains.

However, as a practicing veterinarian with years of experience in canine nutrition and health, I have seen first hand the multifaceted impact of grain-free diets on our canine companions. This article aims to shed light on the disadvantages of grain-free dog food, a topic that has sparked considerable debate and concern within the veterinary community.

As a practising veterinarian, I’ve personally witnessed the varied impact of grain-free diets on our furry friends. This article aims to shed light on the downsides of grain-free dog food, a topic that has sparked significant debate and concern in the veterinary community. So what are the disadvantages of grain free dog food?

What is grain free dog food?

grains in dog food

Grain free dog food is unique in that all traces of wheat, barley, oats, corn and rice are completely removed, and typically replaced with other ingredients, most commonly pulses such as lentils and peas, or else potatoes. This relatively new category of dog food has gained significant popularity in recent years, and the upwards trend is especially prominent amongst USA pet owners, with sales increasing by a staggering 221% between 2012 and 2016. Conversations with pet owners in the consult room in my role as a “GP” veterinarian, as well as data available online, support a single conclusion: grain free diets are big news right now!

My frequent discussions with dog owners have also brought to light a possible reason for this popularity: we see grain free dog food as a healthier choice; more natural, closer in composition to the historical canine diet, which is perceived by many to be entirely prey based with minimal or no carbohydrates. In fact, in one recent survey of US pet owners, approximately half of the respondents reported that they believed grain-free diets were healthier for their pet.

More specifically, grain free dog food is believed to be a superior choice for dogs with digestive issues such as chronic sloppy stools. In my humble opinion as a dog-tor, grain free diets are given a little too much credit in this respect, since the vast majority of dogs can certainly digest grains very effectively and without issues.

It’s true that going grain-free will alleviate allergy symptoms in dogs with genuine grain allergies, but such individuals are actually believed to be a surprisingly tiny percentage of the canine population. So, let’s stay mindful of the statistics; your dog is considerably more likely to be reactive to beef, chicken or dairy products than to grains! To learn more about dog food allergies check out our article.

For those keen to understand the disadvantages of feeding your dog a food devoid of wholesome, highly digestible and energy-rich grains, stay tuned. We have plenty to discuss. 

The Potential Link to Dilated Cardiomyopathy (DCM)

dilated cardiomyopathy grain free dog food

In 2018, a potential link between grain free dog food and the development of dilated cardiomyopathy (DCM; a serious and potentially life-threatening heart condition) was reported by the US Food and Drug Administration. Significant research and in-depth review of the available data has been conducted since, but has done little to offer vets and pet owners a clear answer as to whether or not grain free diets pose a danger to our dogs.

Some studies support a link, and in particular there is concern that grain free diets may contribute to taurine deficiency, which in turn increases the likelihood of DCM developing.

On the flip side, clinical diet trials have shown that feeding grain free has minimal effects on blood taurine levels. Ultimately, the exact role of specific ingredients remains unclear, and since DCM is a complex condition that develops due to an interplay of many factors, experts agree that it’s probably an oversimplification to attribute an uptick in DCM cases to grain free food alone.

In light of the lack of clarity surrounding the potential link between grain free dog food and DCM, my advice to my clients remains as follows: if there’s a genuine, valid reason that your dog needs to be eating grain free dog food, go ahead. If there isn’t, I recommend you go with a food that includes grains.

Nutritional Deficiencies

nutritional deficiency dog food

High quality, commercially available grain free dog food should be formulated to include everything your dog needs and to meet all of his or her nutritional needs. So, provided you select the product carefully and ensure you’ve chosen a “complete” rather than “complimentary” dog food, serious or dangerous nutritional deficiencies should not be a problem.

If in any doubt as to whether or not a food is suitable to feed daily as your dog’s sole diet, don’t be afraid to ask! In most cases it’s possible to contact the manufacturer’s technical team directly via email or phone.

Those of you already feeding grain free who have noticed your pooch producing particularly firm poops may be interested to learn that grain free diets are often lower in fibre compared to their grain-containing counterparts. This means feeding grain free can potentially instigate or exacerbate constipations in prone individuals. If this applies to your pet, consider whether you really need to be feeding grain free. You can also consider adding a fibre supplement to your dog’s diet. Speak to your vet if you’re uncertain which supplement is best suited for your dog. 

Cost Considerations

Talk is cheap, and so are grains! Since wheat, barley, oats and co. are produced in bulk across much of the globe and cost relatively little to produce, diets that contain grains are often (although not always) cheaper than opting for a grain free alternative. So, those with cost concerns may find it easier on the wallet to select a dog food that contains grains.

Grain-Free Diet Misconceptions

By far the most common misconception I come across in my role as a veterinarian is that owners think their dog will struggle to digest grains. In reality (and thanks in part to evolving alongside carbohydrate-loving humans, as man’s best friend), dogs happen to be really quite good at digesting grains!

In my experience – and yes, this is anecdotal but still worth noting – a really big percentage of dog owners self-diagnose their pet as having a grain allergy or intolerance. Let’s cast our minds back to the introduction for a second: your dog is far more likely to be allergic to beef, chicken or dairy products than grains, so I’d always advise ruling out the more likely potential causes of digestive issues first, before pinning the blame on grains.  

Alternative Diet Options

alternative diet dog

The alternative to feeding grain free is to select a food that includes grains: welcome back,  wheat, barley, oats, corn and rice! Options include kibble, “wet” processed dog food (loaf, cans, sachets), “fresh” dog food (commercially made or home cooked), raw, and freeze-dried raw foods.

It’s best to avoid feeding raw (see ‘What dog foods to avoid’ below). If you decide to produce a home cooked diet for your dog, be sure to consult with a qualified veterinary nutritionist to ensure the end product is complete and balanced and to avoid any nutritional deficiencies or excesses.

What dog foods to avoid?

This is my favorite question, because the answer can make a really massive difference to both human and animal health! As a preface (and to hopefully show you just how passionate I am about this subject), whilst studying to become a veterinarian I actually completed my dissertation as well as a funded research project investigating raw food diets for dogs. The conclusion? Please don’t feed your dog raw meat!

Feeding raw meat is hazardous for humans handling the food and those coming into contact with the dog or their stools. It also encourages the development and spread of antibiotic-resistant strains of bacteria; and it has absolutely no benefit for your dog that can’t equally (and much more safely) be obtained by feeding a carefully selected, fresh and complete diet. See our full article that covers whether raw meat diets are safe for dogs.

In considering what dog foods you should avoid, I also feel obliged to give a nod in the direction of advanced glycation end products, or AGEs. An increasing awareness and concern regarding these unwelcome little molecules is prompting many owners not to feed kibble or other forms of processed dog food. So, what actually are AGEs? 

To put things simply, advanced glycation end products are a potentially harmful group of compounds produced in relatively large amounts when sugars and proteins interact following certain food processing practices, including heating food to very high temperatures (such as during the production of kibble). AGEs build up in the body and have been linked to a number of age-related diseases in both humans and dogs. It’s a relatively new area of research and there is still much to be learned, but limiting your pet’s intake of AGEs may help them live a longer and healthier life.

Again, this area is complex but the key point is that minimally processed foods are often the better option, provided you still ensure your dog’s diet is complete and balanced. Companies providing meals that are formulated by a veterinary nutritionist and freshly prepared using “gentle” cooking methods are a great alternative.


Why does my vet not recommend grain free dog food?

Different vets will have different opinions when it comes to the topic of grain free dog food; there’s not really one single, firm consensus within the veterinary community regarding whether or not to feed grain free!
If your vet is recommending not to feed grain free dog food, it’s likely because they feel your dog doesn’t need to go grain free. As we’ve already mentioned, only a minority of dogs are likely to benefit from cutting out grains. Of course, the best thing to do if you’re not sure why your vet doesn’t recommend grain free dog food is to ask them! We’re here to help and advise, so please never be afraid to let your vet know if you need further information or feel something hasn’t been fully explained.

Is dog food better with or without grain?

Based on the available evidence, I recommend that my clients only feed their dog grain free food if there is a valid reason to do so, for example a known or suspected grain allergy or intolerance. Grains are a great source of energy, fibre and antioxidants, as well as being cheap and readily available; in my opinion, they have an unfairly bad rep! 


To conclude, whilst grain free dog food has certainly soared in popularity in recent years, it’s important to consider the possible downsides to this form of diet, as well as whether or not it’s really necessary to cut grains out of your dog’s diet completely.

Whilst going grain free may be perceived as the healthier choice, this perception is not necessarily based in fact. Ultimately, the very best advice I can give you is to select a diet based on evidence rather than hearsay.

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