Keeping PETS out of vets since 2011

Some Crucial Notes on Vegetarian Dog Food…

lewis hamilton vegetarian pet food

Vegetarian pet food – how right is it for my dog?

Recently Lewis Hamilton revealed on his dogs instagram account (250k followers, honestly) his dog is now fully vegan. It was as a result of his other bulldog Coco dying months previously. The dog suffered a myriad of health issues and it was that encouraged Hamilton to consider what he was feeding his dogs. Hamilton stated: 

Our pets deserve the best we can give them…since he has gone vegan, his coat is much softer, his swollen paws have healed up…he is no longer limping with the pain of arthritis and his breathing has opened up.”

Considering his following (I’m ten years in the business and have one tenth of the following of his dog on Facebook, as an example) we need to unpack this quick as very undoubtedly Hamilton has pushed unknown numbers of pet owners towards vegetarian diets for, what appear to any sane person looking in, meat eaters (if not totally, then very largely). 

What does the science say about vegetarian dog food?

While most of us feed a bit of veg (I certainly recommend it, 5-10% of the diet, for all these reasons), very few of us think meat can be cut out of the diet completely without health ramifications for the animal down the line. We try to feed species appropriately here – what do free-roaming, feral domestic dogs eat in the wild, OK that’s what you get. So this is clearly no place to ask who thinks a veggie diet is a good idea for a dog. The results will be highly skewed towards Lewis Hamilton should stick to racing cars. What we need to focus on is what the studies say.

The EuroNews piece above quoted an animal behaviourist James Carroll who said 

…a good vegan dog food seems to be on par with meat-based dog food…at least according to a two-year study which compared the two. Dogs at the end of the research had nutrient surpluses which were similar to each other, but varying nutrient deficiencies – with more deficiencies in the meat-based diet.”

Now, anyone looking in would see this as a resounding success for vegan pet food. But what does James mean by meat-based dog food? Well, as you are soon to find out, he is referring to a study that compared vegan pet food to pets fed cereal-based pet food. Once this stuff is mentioned all thoughts of actual “meat” being in there should dissapear quicker than Hamilton’s ass in a Ferrari.

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In an effort to get to grips with who feeds what, an interesting study analysed the pet food feeding habits 3,673 pet owners, categorising them as veggie, vegan, pescatarian (eats fish) or omnivore (eats meat and plant). It revealed that 26% of vegans feed a diet with meat to their carnivorous pets. Respect to these vegans. That’s not an easy thing to do, no doubt. But what was particularly interesting was that 91% of pet owners reported at least one concern regarding strictly plant-based or ‘vegan’ pet foods. If only they knew they were already feeding a virtually-vegan dry food already. 

We know cereal-based pet food rarely contains more than a token amount of “meat”, usually in meal form and meal is surely the among. the lowest forms of protein on the planet. In fact, if your product says “with beef” there can be as little as 3% meat meal in there. 

what does with mean in pet food

This means, despite the glorious image of sizzling steaks that they put on the front label to make you think that kibble is brown because of all the meat in there, folk feeding such veterinary-recommended crud are already feeding their dogs a virtually vegetarian meal anyway! 

In fact, with meat-meal being such highly processed food waste and thus potentially antigenic to the body, maybe the dog is better off without it in there at all!

For these reasons, perhaps we shouldn’t be so surprised when a “complete”, plant-based kibble carefully made by well-meaning vegetarians on whole vegetable ingredients, with all the bioactive compounds etc therein, can compare and even out-compete the typical “meat-containing”-but-very-largely-cheap-cereal-based-dry-crud over time, a product that has none of the fancy veg ingredients. 

Here’s a segment from my new, best-selling book Feeding Dogs (references are in the book!) that highlights some plant-based pet food success stories:

Semp (2014) followed 20 dogs and 15 indoor cats fed a vegan diet. Participating dogs had eaten vegan diets from six months to seven years, with a mean of 2.83 years. Bloods were then taken to analyse the state of liver, kidney and pancreas as well evaluate nutrient levels and compared to 20 ‘healthy’ dogs fed a conventional, dry, cereal-based pet food. They found:

• 5/20 (25%) vegan-fed dogs were outside the reference range (RR) for Vitamin B12, compared to 7/20 (35%) of conventionally-fed dogs.
• 2/19 (11%) vegan-fed dogs were outside the RR for iron, compared to 5/20 (25%) of conventionally-fed dogs.
• All vegan-fed dogs had adequate protein, 2/20 (10%) of conventionally-fed dogs did not.
• 5/17 (30%) vegan-fed dogs were outside the RR for folic acid, compared to 5/20 (25%) of conventionally-fed dogs.
• 3/7 (43%) were outside the RR for L-carnitine, compared to 12/20 of conventionally-fed dogs (60%).

Semp is not alone. Kienzle and Engelhard (2001) studied 86 vegetarian dogs and eight vegetarian cats in Germany, Switzerland and Belgium. The authors, using the AAFCO feed guidelines, were only able to recommend two without reservation. Gray et al. (2004) analysed Evolution canned complete diet for adult cats and found it to be deficient in taurine, methionine and arachidonic acid as well as deficient in several B vitamins, retinol, calcium, phosphorus and overall protein. Kanakubo et al. (2015) examined 13 dry and 11 canned vegetarian diets for dogs and cats. They found 25% did not meet all amino acid minimum requirements for the animal in question.

That said, Section 2 adequately demonstated that cereal-based pet food fails just as much, if not more so, to meet the minimum targets they set for themselves (94% of the ‘complete’ canned food and 62% of the ‘complete’ dry foods sold in the UK were not compliant with FEDIAF / AAFCO guidelines).

In science, it’s all about the control group – to whom are you comparing your results?

Such works convince many folk that feeding meat eaters upon a plant-based diet is absolutely fine. And I would agree…but only if, for your comparison, you are using cereal-based pet food which, in virtually everyone’s opinion looking in, is one of the poorest food substrates you could feed your pet.


As evidence that plant-based diets are fine to feed dogs, our very own celebratory vet Pete The Vet, uses a single reference. It was a small study of sled dogs.  I love studies using working dogs. They’re the real test of something. Pete tells us one group of dogs were fed plant-based kibble and the other cereal-based kibble. They performed equally well. I don’t doubt it.

But had Pete, currently the brand ambassador for Nestlé Purina, dug just a little deeper he would of course found all the studies of sled dogs that scream cereal-based pet food is not working out for sled dogs. Again, taken from my book Feeding Dogs:

…more often than not, sled dogs are not fed carbohydrates (Kronfeld et al. 1973, Hinchcliff et al. 1977, Loftus et al. 2014). In fact, Kronfeld et al. (1973), a giant of the sled-dog field, later went on to run his sled dogs on three different diets – one group were fed a high-carbohydrate diet, the other a medium carbohydrate and the third zero carbohydrates. No adverse effects were observed in dogs fed the zero-carb diet (Kronfeld et al. 1977). On the contrary, dogs on this diet maintained higher serum concentrations of albumin, calcium, magnesium and free fatty acids during the racing season. They also exhibited the greatest increases in red cell count, haemoglobin concentration and packed cell volume during training (all of which would increase your fitness), the authors concluding that a carbohydrate-free diet “appeared to confer advantages for prolonged strenuous running in terms of certain metabolic responses to training…

…sled dogs were maintained at 16, 24, 32 and 40% of their calories from high-quality animal protein. The dogs fed the highest protein level maintained a larger plasma volume and red blood cell mass during strenuous training (Reynolds et al. 1996). Moreover, all of the dogs consuming the low-protein diet had at least one injury during the racing season that resulted in it being removed from training for a minimum of one week. Those dogs consuming the highest amount of protein were injury free…

Study indicates raw-fed dogs are healthier than dogs fed cereal-based pet food… 

These are the sorts of studies you do not hear discussed by dry-feeding vets the world over because it does not suit the narrative. The fact is race dogs run on plant ingredients about as well as cars do. As a vegetarian myself, I sincerely wish it was different, but it’s not. 

Feeding Dogs book

And these studies are but the tip of the iceberg. There are numerous words showing dogs do better when fed raw over dry (how many have you seen that indicate “complete” dry outcompetes a well balanced raw?!). Just one more teaser from my book:

In 2015 Roine et al. (2015) set out to measure the metabolite levels in dogs suffering atopy. In particular, they were looking at homocysteine, a by-product of the metabolism, which is related to a number of diseases. Dogs suffering allergy/immune responses have higher levels of it in the blood. It’s fair to say it’s something you’d like to see less of in the body.

What they found was indicative of everything we have discussed above. First, dogs eating raw food had 0.17mM homocysteine in their blood. Dry-fed dogs had 1.57nM, nearly a ten-fold increase. But even more remarkably, when raw-fed dogs were moved to dry they suffered a near five-fold increase in homocysteine (from 0.17 to 0.77nM) while dry-fed dogs changed to raw enjoyed a five-fold decrease in homocysteine (from 1.57mM to 0.30mM).

They followed up this work with a paper presented at 42nd WSAVA Congress in 2017. They found that, compared to raw, dogs eating a dry diet showed a highly changed regulation of genes in the skin, proving dry food seems to have a dramatic impact on skin gene expression.14 These findings were verified by Anderson et al. (2018), using Peripheral Blood Mononuclear Cell (PBMC) gene expression, micro-array profiling. This catchily named technique is a minimally invasive tool commonly used in human diet intervention studies. They concluded that a meat diet was associated with a decrease in cytokine gene and receptor expression compared to a kibble diet. The kibble-fed dogs had increased expression of immune-related genes/pathways and elevated plasma IgA concentrations. 

This work paints a very clear picture – in comparison to raw dog food, dry food is likely causing a lot of inflammation in dogs. Whether this is due to its high cereal content, high chemical content, the types of protein used, the lack of fresh fats or maybe even processing technique, remains unknown.

Raw versus dry fed dogs

This is why simply switching your dog from ultraprocessed dry to raw seems to fix many of those recurring, itchy skin conditions

All the evidence points towards cereal-based pet food as not working out for dogs, that they do better when fed well balanced, species-appropriate food. This is because far from being simply protein and fat, meat contains a raft of bioactive compounds not found in the plant kingdom, items your dog has spent millions of years evolving to need, items that are not, indeed cannot be replaced by pet food manufacturers with their conical flasks, any more than they can get the really important life-affirming bits into baby milk formulas.

While Hamilton has built a life and career around coming first, as his pets sole provider, he’s going to have to accept his personal beliefs coming second in this one.


[I must add: I understand the concept of feeding meat protein will be hard for some but even if half his diet was a variety of the most ethical meat-products you can find he would do significantly better.]

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"Finally! A well-written, well-referenced thorough examination of the raw dog food debate. A fantastic gift for your favourite veterinarian."
Dr. Karen Becker


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