Frequently asked questions

Diet choice

Which vegan diet should I choose?

It is important to feed diets that are nutritionally-sound. A small minority of the diet could be treats/snacks, but the great majority should be nutritionally-sound. To ensure this, check product labels to confirm the diet is nutritionally complete and balanced, and purchase diets only from reputable companies that are working with veterinary nutritionists or other nutritional experts, to formulate diets that are nutritionally-sound. The company should also be able to provide some reasonable information about steps taken to ensure nutritional soundness, on their website or in response to inquiries. The gold standard is independent laboratory analysis confirming diets match nutritional guidelines provided by EU, US or other authorities. However, this is expensive for companies, and hence uncommon. But companies should be able to provide some reasonable information about steps taken to ensure nutritional soundness and quality/consistency of diets. If not, choose another company.

Health and nutrition

Are cats obligate carnivores?

Yes. That means that in their natural environments, they needed to hunt/kill prey animals to survive. Is that relevant to modern domesticated house cats fed diets comprised of ingredients they’d never naturally eat (e.g. fish, farmed animals, plants, vitamin additives, flavorants, colorants, etc), in unnatural formulations (e.g. kibble), at unnatural times (e.g. twice daily or ‘at will’ – always available)? No – it’s not very relevant.

Do cats need to eat meat?

No. Cats (or dogs, or people) don’t need any particular ingredient. They all need specific nutrients. People often forget these are not the same thing. Vegan and other alternatives diets aim to supply all necessary nutrients, from plant, yeast, mineral or synthetic sources. The largest scientific study published so far examining the health of vegan cats studied > 1,000 cats. Cats on nutritionally sound vegan diets were more likely to be rated as very healthy, and less likely to suffer body weight, gastrointestinal or liver problems, than those on meat diets: https://doi.org/10.1186/s12917-021-02754-8.

In all other respects studied, there were no significant differences between the two groups. This was published recently, in one of the world’s top veterinary journals. No scientific study is ever perfect, but this is a very large and robust study, in a leading veterinary journal, and its conclusions are much more likely to be true, than untrue. It also concurs with results of previous studies showing similar outcomes

Are pets fed vegan diets more likely to suffer nutritional deficiencies?

This is a good question. Any animal on a nutritionally deficient diet (vegan or meat-based) will eventually suffer deficiencies. Any on a nutritionally sound diet (vegan or meat-based) will not suffer nutritional deficiencies. So, are vegan diets more, less or equally likely to be nutritionally deficient? Perhaps, slightly less likely, according to our recent, in-depth study of pet food manufacturing processes. This is evidenced in our recent scientific study ‘The nutritional soundness of meat-based and plant-based pet foods’ at www.andrewknight.info/articles/pet-food-health > ‘The nutritional soundness of meat-based and plant-based pet foods’. There is certainly no evidence, that vegan pet foods are more likely to be nutritionally deficient or of lower quality. But there is significant evidence they’re less likely to contain potentially hazardous ingredients.

Can vegan diets reduce allergic conditions?

Dietary allergens commonly cause conditions such as itchy skin and ears, and gastrointestinal reactions. Multiple studies show these are less common when (nutritionally-sound) vegan diets are fed. Pet guardians are often surprised to learn that many dogs and cats are allergic to or intolerant of animal proteins. An animal-free diet can be a remedy for common allergies and inflammatory conditions, such as inflammatory bowel disease (IBD).

Small animal veterinary nutritionist Cailin Heinze said that contrary to popular opinion, “It’s much more common for dogs to have allergies to meat than to grain,” with chicken, beef, eggs, dairy, and wheat causing the most common allergies in dogs. (Gallegos, J (2017). Grain-free pet foods are no healthier, vets say. Focus on this nutrition issue instead, Washington Post).

A 2016 study revealed that animal-based ingredients (beef, dairy, chicken, lamb, egg, pork, fish, and rabbit) were responsible for 236 cases of food allergies in dogs. By contrast, plantbased ingredients (wheat, soy, corn, rice, barley, kidney bean, and tomato) were responsible for only 77 cases. (Mueller, RS., et al (2016). Critically appraised topic on adverse food reactions of companion animals: common food allergen sources in dogs and cats. BMC Veterinary Research).

Animal nutritionists Richard and Susan Pitcairn highlight that eight out of ten of the top allergens in pet foods are animal products. (Dr Pitcairn’s Complete Guide to Natural Health for Dogs & Cats, 2017).

‘cats cannot digest ingredients in vegan diets’

There is no evidence of this, but there is good evidence to the contrary, because at least two peer-reviewed studies in top veterinary journals, studying large numbers of cats on vegan diets long-term, have shown health outcomes as good or better than cats on meat-based diets (https://sustainablepetfood.info/vegetarian-feline-diets/#3). No study has ever been published, showing the opposite. This would not be possible, if cats could not digest ingredients in vegan diets. Clearly and demonstrably, they can.

Aren’t these studies based on pet owner opinions? These are not reliable.

The benefits and limitations of asking pet guardians about their opinions are already very thoroughly addressed in the relevant studies – please read the ‘Study limitations’ sections of those studies. Additionally, by 2024 there were close to 15 health studies, including studies utilising blood tests, x-rays, veterinary clinical examinations, clinical histories, veterinary health assessments, owner opinions, and other data such as rates of medication use, medical diet use and veterinary visits. Most of these were long-term studies and some very large-scale. In the face of all of this evidence, choosing the contrary position (that vegan diets are less healthy), which is supported by only 1 study of much lower quality than nearly all of the above, is the unscientific approach. Whilst it’s true that any individual study in virtually any scientific field can usually be critiqued, the scientific (and logically correct) position is the one best supported by the weight of evidence, and by sound reasoning. In this case, the weight of accumulated scientific evidence and sound reasoning both support the use of nutritionally-sound vegan diets. Everyone is welcome to their personal opinions, of course, but if these are contrary to most of the evidence in a field, opinions should not be represented as evidence-based. If inconsistent with the clear weight of evidence on an issue, then such opinions demonstrate personal bias.

Concerning ‘bias’

Bias is demonstrated, when someone persists in believing in a particular position, contrary to evidence. Such a position is, for example, the belief that cats or dogs (or people) cannot be healthy on nutritionally sound vegan diets. A similar belief is that cats or dogs suffer from being fed vegan diets. There have always been a large number of case studies, but there are now also a growing number of scientific studies of these matters as well. These are being added to www.sustainablepetfood.info. The evidence so far is very consistent: cat, dogs and people are generally at least as healthy when fed nutritionally sound vegan diets, and also experience certain health benefits, some of which can be quite important. Meat-based pet food has a very considerable environmental impact. And as far as we can establish from analyses of their behaviour at mealtimes, cats and dogs do not suffer when fed vegan diets. People are of course always welcome to express personal opinions that disagree with any of these points. But these are personal opinions, contrary to what is now a considerable, and consistent, body of scientific evidence. Instead of accusing others of bias, some of these people would do well to acknowledge that their positions reflect their own personal biases, and will continue to do so, as long as they contradict the consistent scientific evidence on these matters. Alternatively, they could consider that scientific knowledge (and pet food manufacturing) evolve over time, and that what used to be considered ‘gospel’ in this field – as with many others – might now be out of date. Understandable perhaps, given that several of these studies have been published only very recently. Concern for the welfare of cats and dogs fed vegan or meat-based diets is reasonable. But ignoring the accumulated evidence that now exists in this field, is not.

Pet welfare

Is it cruel to feed dogs and cats a vegan diet?

Apparently not, according to the largest scientific study ever conducted on their behaviour at mealtimes: 2,308 dogs and 1,135 cats: https://doi.org/10.1371/journal.pone.0253292. ‘Major new study indicates pets equally happy on vegan and meat-based diets’

Could feeding a vegan diet could lead to criminal prosecution?

Knowingly feeding any diet long-term, that was nutritionally deficient, could lead to prosecution – whether the diet was meat-based, or vegan. Studies have shown some diets in all dietary groups have been formulated incorrectly and have various nutritional problems (e.g. Hill et al. 2009, analysing 2,208 pet foods manufactured by 204 companies – virtually all pet foods with problems were actually meat-based). However, feeding diets that are formulated to be nutritionally-sound – whether meat-based or vegan – would not result in successful prosecution. So, are plant-based diets formulated to be nutritionally sound, with good quality control? Yes, according to our recent detailed study of pet food manufacturers: www.andrewknight.info/articles/pet-food-health > ‘The nutritional soundness of meat-based and plant-based pet foods’. “… most manufacturers had acceptable or superior standards at nearly all stages examined … with plant-based diets slightly superior to meat-based diets overall.” i.e. nutritional soundness and good quality control are crucial. Both vegan and meat-based diets, can meet or fail these standards, but this evidence does not indicate any greater reason to be concerned about vegan diets, than about conventional diets. This – in combination with the other scientific evidence in this field – would normally result in clear failure, of any attempt to prosecute any person, for feeding a nutritionally sound vegan diet to cats or dogs.

Animal-by products

Don’t the animal-by products used in pet food decrease the environmental footprint of pet food? Isn’t this beneficial recycling of waste products of human meat production?

Interestingly, the animal-by products (ABPs) used in pet food actually increase (quite substantially), rather than decrease, the environmental impact of pet food (as their production actually requires more, not less, livestock animals). Their use in pet food is simply to lower production costs/increase profits. It is not beneficial recycling of products that would otherwise go to waste. If not used in pet food, ABPs would be consumed in the manufacturing of a wide variety of other products. These factors are calculated and explored in detail within the study https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0291791 > Discussion > Animal by-product use within society.

Raw meat and insect-based diets

What about raw meat diets?

These diets are frequently found to include pathogenic hazards (with subsequent infections of both people and pets), and nutritional imbalances and deficiencies, and multiple product recalls have resulted. A sizeable body of studies published in the biomedical literature illustrate the hazardous ingredients sometimes found within meat-based pet food, and the diseases that may be associated with long-term maintenance on such diets. Numerous studies reported in peer-reviewed scientific journals have demonstrated that such diets may be contaminated with a variety of pathogenic organisms, including Salmonella spp, Campylobacter spp, Clostridium spp, Escherichia coli, Listeria monocytogenes, and enterotoxigenic Staphylococcus aureus. Dogs and cats may develop foodborne illness after being fed animal-sourced protein contaminated with these organisms. Apparently healthy dogs and cats can also develop subclinical infections with these organisms and pose a risk to other animals and humans, especially young, elderly, pregnant, and immunocompromised individuals. People handling contaminated pet foods are also at risk of becoming sick. Accordingly, very few veterinarians recommend raw meat diets, and we certainly do not.

What about insect-based pet food? Isn’t that also environmentally sustainable?

“Instead of helping the environment, in practice insect farming mostly adds an inefficient and expensive layer to the food system we already have” – see The Guardian.

Miscellaneous

Are vegan diets more expensive?

Some are, some aren’t. (i) new products are coming fast, so more cost affordable options will come in time, (ii) vegan pets need to visit vets less and need less medications, and are generally healthier, according to recent studies (https://sustainablepetfood.info > Health). Vet treatment for ongoing illness can cost more than food – ie (as with preventative healthcare generally), preventing worse health (rather than trying to treat it) is the cheaper option (and much better for welfare too!)

What is the British Veterinary Association position on vegan pet food?

On 24th July 2024, the BVA publicly ended its opposition to (nutritionally-sound) vegan dog diets. Further information.

Is this some kind of attempt to sell products or make money?

No. www.SustainablePetFood.info is an informational site. No funds are received at all. The information there comprises scientific articles and summary articles about this issue. This is currently a fast-developing field. A suite of studies have very recently been published, and are forthcoming, and are being added to the site. Essentially, these studies show that conventional pet food has a very significant ecological ‘paw print’. And that cats and dogs maintained on nutritionally sound vegan diets suffer no adverse health effects, may experience several health benefits, and are just as happy with their food, as far as we can determine from detailed analysis of their behaviour. If we are to successfully meet the challenges of climate change (not to mention pandemics), then ‘business as usual’ is not an option. We do need to rethink our lifestyles, and this does include our traditional reliance on meat-based pet food, which has a much bigger ‘ecological paw print’ than most of us realise. The scientific evidence is now considerable, consistent, and it supports such change.