A new study has shown that there are very large environmental benefits associated with nutritionally sound vegan diets for dogs and cats, as well as people. After analysing pet food ingredients in detail, as well as food consumed by humans, Veterinary Professor Andrew Knight calculated that the world’s dogs and cats consume around 9% of all land animals killed for food, or around seven billion animals annually, as well as billions of fishes and other aquatic animals. 

In this study published in PLOS ONE in October 2023, and titled “The Relative Benefits for Environmental Sustainability of Vegan Diets for Dogs, Cats, and People”, Knight calculated that if all the world’s dogs were fed a plant-based diet, it would reduce more climate-changing greenhouse gasses emissions than all those emitted by the UK, it would save land larger than Mexico, it would save freshwater exceeding all renewable freshwater in Denmark, and would feed around 450 million additional people. He also calculated that if all the world’s domestic cats were fed a plant-based diet, it would reduce more greenhouse gasses emissions than all those emitted by New Zealand, it would save land larger than Germany, it would save freshwater exceeding all renewable freshwater in Jordan, and would feed around 70 million additional people. Finally, if all humans went vegan, it would reduce more greenhouse gasses emissions than all those emitted by the entire EU, it would save land larger than Russia, it would save freshwater exceeding all renewable freshwater in Cuba, and it would feed around 5.3 billion additional people — more than every single nation or collective region on Earth as defined by the World Bank.

Professor Andrew Knight said, “This study is game-changing. We’ve long known that plant-based diets are better for the planet, but have not seriously considered the impacts of pet food. However, pet food has profound environmental impacts. Conversely, very large environmental benefits can be achieved by nutritionally-sound vegan pet food. Large-scale studies have also shown that health outcomes for both dogs and cats are as good or better. And studies of feeding behaviour have demonstrated that average dogs and cats enjoy vegan pet foods as much as those made from meat. Pet owners who care about the environment or their animals’ health should consider nutritionally-sound vegan pet food. However, to safeguard health, it is important that people feed only commercial diets labelled as nutritionally complete, produced by reputable companies with good standards.”

There are now nine studies in dogs, and three in cats, showing good health and behavioural outcomes for companion animals fed vegan diets. The most recent very large-scale study showed positive health outcomes in cats fed plant-based diets. 

“Originally from Catalonia, but resident in the UK for several decades, Jordi is a vegan zoologist and author, who has been involved in different aspects of animal protection for many years. In addition to scientific research, he has worked mostly as an undercover investigator, animal welfare consultant, and animal protection campaigner. He has been an ethical vegan since 2002, and in 2020 he secured the legal protection of all ethical vegans in Great Britain from discrimination in a landmark employment tribunal case that was discussed all over the world. He is also the author of the book, ‘Ethical Vegan: a personal and political journey to change the world’.