Can you feed your dog or cat a plant-based diet?

Why plant-based pet food could be better for our planet and our pets

For many people, it’s conventional wisdom that dogs and cats need a meat-based diet. However, recent research suggests that there is little evidence of negative health outcomes in dogs and cats that are fed nutritionally complete plant-based diets. On top of this, we’re becoming more aware of the environmental harms associated with meat-based diets, when it comes to feeding both ourselves and our companion animals.

In this blog, we highlight some research that might prompt you to rethink your animal companion’s diet. If you’re considering giving your companion animal more plant-based food, make sure to look for high quality, commercially available, nutritionally complete food, rather than relying on homemade foods.¹ And if you’re in any doubt, consult your veterinarian for more guidance. 

Dogs and cats have large environmental ‘paw prints’

Dog and cat food account for 95% of global pet-food sales. Using conservative estimates, in the US alone, the diets of dogs and cats account for 20% of all livestock animals consumed, while, globally, it’s 9%. This has a big impact on the environment.²

One study estimated that pet food is responsible for 25–30% of the livestock sector’s environmental impacts in the US.³ Another found that if all dogs transitioned to a nutritionally sound plant-based diet, the reduction in global GHG emissions would be greater than all GHG emissions from the UK.⁴ Given the urgent need for climate-change mitigation measures in all aspects of our lives, the food that our companion animals eat represents a substantial opportunity for change.

Research suggests that dogs and cats can maintain good health on a nutritionally complete plant-based diet 

It is often assumed that dogs – and cats, especially – cannot consume a solely plant-based diet, and that meat is a necessity for our companion animals. 

However, as veterinarian and researcher Andrew Knight notes, from a biological perspective, companion animals don’t necessarily need meat, but rather a specific set of nutrients. There’s no scientific reason why all the necessary nutrients cannot be supplied through plant additives.⁵

This is particularly important for cats who, as obligate carnivores, do require nutrients not found in plants. In contrast, dogs, who are omnivores, are able to fulfil all their nutritional needs with plant-based ingredients. 

A range of recent studies suggest that nutritionally complete plant-based diets appear to be safe. In fact, they may even lead to better outcomes for dogs, and perhaps also for cats, compared to conventional meat-based pet food. This conclusion is supported by both clinical studies and mass-survey studies. A comprehensive list is available here (dogs) and here (cats). 

A survey of 2,536 European dog owners found that self-reported indicators of their animal’s health were worse on conventional meat-based pet diets compared to plant-based diets.⁶ A survey of 1,418 cat guardians also found a clear and consistent trend that cats who are fed plant-based diets tended to be healthier than cats who are fed meat-based diets.⁷

A systematic review of the research into this topic (including both clinical and mass survey studies) concluded that there is little evidence of adverse effects arising in dogs and cats who are fed plant-based diets, and recommended a cautious approach using commercial foods for those who wished to feed their animal companion a plant-based diet.⁸

So far, the research suggests that meat isn’t necessary for our animal companions, and that plant-based diets don’t appear to be any less healthy than meat-based ones – in fact, they might even be healthier. 

The environmental impacts of companion animal diets is set to increase – unless we change things

As the human population has grown and countries have developed, we’ve seen a rapid increase in global dog and cat populations that seems likely to continue. We can see this in pet food trends – over the next four years, the global market for pet-food ingredients is expected to increase by nearly 40% compared to 2022 (from $32.2 billion to $44.5 billion).⁹ This means that, if we don’t change the way that pet food is manufactured, its environmental impact is likely to increase significantly in the coming years. 

We already know that human meat consumption is projected to increase, and that a shift from animal-based to plant-based diets is crucial if we are to meet sustainability targets and mitigate rapid climate change. It’s now also becoming increasingly clear that the importance of dietary change is not limited to humans. Changing the diets of our companion animals represents a key and neglected opportunity to make a positive impact on the environment. 

The deaths of billions of animals could be avoided

Additionally, there are significant animal-welfare benefits from companion animals eating plant-based diets. As we saw above, the diets of dogs and cats comprise 9% of all livestock consumption globally, and 20% in the US. This is in part due to our increasing devotion to companion animals, prompting owners to feed their animals human-grade meat products. Plant-based pet food represents a huge opportunity to avoid the deaths of countless animals. The numbers are staggeringly large: if all the world’s dogs and cats were fed plant-based diets, the deaths of 7 billion animals could be avoided every year.¹⁰

Conclusion

The environmental and animal welfare benefits of feeding our companion animals plant-based food are clear and significant. At a time when we need every tool at our disposal to combat climate change, if we can reduce the environmental impact of our companion animals’ diets, we should surely do so. 

So far, the research into this question suggests that we can. Current evidence suggests that plant-based diets for dogs and cats are not only nutritionally adequate, but might even be healthier than meat-based diets. 

With a growing range of nutritionally complete plant-based pet foods entering the market, it’s becoming easier to transition your companion animal to a plant-based diet. For more information on plant-based companion-animal diets and commercially available products, see here. Growing evidence on the health and environmental outcomes of plant-based food suggests that there is no good reason not to make the change, and compelling reasons to do so. 

Billy Nicholles 

New Food Hub Writer

1. For a comprehensive list of good brands for dogs, see: Sustainable Pet Food Association (n.d.): Sustainable and Nutritionally Balanced Plant-Based Dog Foods. Available at: https://sustainablepetfoodassociation.co.uk/inspiring-businesses. Accessed 2024-31-01
2. Knight, A. (2023): The relative benefits for environmental sustainability of vegan diets for dogs, cats and people. PLOS ONE 18(10), e0291791. doi:10.1371/journal.pone.0291791
3. Okin, G. S. (2017): Environmental impacts of food consumption by dogs and cats. PLOS ONE 12(8), e0181301. doi:10.1371/journal.pone.0181301
4. Knight, A. (2023): The relative benefits for environmental sustainability of vegan diets for dogs, cats and people. PLOS ONE 18(10), e0291791. doi:10.1371/journal.pone.0291791
5. Devlin, H. (2023): Cats may get health benefits from vegan diet, study suggests. The Guardian. Available at: https://www.theguardian.com/lifeandstyle/2023/sep/13/cats-may-get-health-benefits-from-vegan-diet-study-suggests. Accessed 2023-12-21.
6. Knight, A., E. Huang, N. Rai, et al. (2022): Vegan versus meat-based dog food: Guardian-reported indicators of health. PLOS ONE 17(4), e0265662. doi:10.1371/journal.pone.0265662
7. Knight, A., A. Bauer & H. Brown (2023): Vegan versus meat-based cat food: Guardian-reported health outcomes in 1,369 cats, after controlling for feline demographic factors. PLOS ONE 18(9), e0284132. doi:10.1371/journal.pone.0284132
8. Domínguez-Oliva, A., D. Mota-Rojas, I. Semendric, et al. (2023): The Impact of Vegan Diets on Indicators of Health in Dogs and Cats: A Systematic Review. Veterinary Sciences 10(1), 52. doi:10.3390/vetsci10010052
9. Knight, A. (2023): The relative benefits for environmental sustainability of vegan diets for dogs, cats and people. PLOS ONE 18(10), e0291791. doi:10.1371/journal.pone.0291791
10. Knight, A. (2023): The relative benefits for environmental sustainability of vegan diets for dogs, cats and people. PLOS ONE 18(10), e0291791. doi:10.1371/journal.pone.0291791