Cats and Dogs have nutrient requirements, which are not the same as ingredient requirements. Nutrient requirements can be fulfilled from plant mineral and synthetic sources, and they don't need to have a specific list of ingredients such as fish or meat in their diet in order to be healthy.
In 2020, Prof Andrew Knight and his colleagues did a research of health outcomes of over 2500 dogs on 3 diets; conventional diet, raw diet and vegan diet.
They assessed on 7 general indicators of health such as multiple visits to the vets, medication use, percentage of unwell animals…. and they also examined the prevalence of 22 of the most common disorders suffered by dog.
The proportion of dog considered unwell were as the number in the table below:
Conventional meat diets produce health outcomes that were inferior to those produced by other 2 diets. Some of the dogs were fed raw meat diets who were marginally more healthy than the vegan dogs in general.
“But those dogs were significantly younger, which gives them a health advantage” said Prof Andrew Knight.
Additional, raw meat might bring considerable risk of pathogens such as bacteria and parasites that are not associated with vegan diet.
Based on this study, “the healthiest and least hazardous dietary choices for dogs are nutritionally sound vegan diet” said Prof Andrew Knight
He also advises that the guardians should choose reputable pet food companies who work with veterinary nutritionists to ensure the products they produce are nutritionally complete and balanced.