Many people now a days maintain a vegan diet for various different reasons. While veganism in people can be healthy, the same doesn’t apply to our pets, especially cats. Cats are known as obligate carnivores, which means they need to eat meat in order to get certain amino acids and vitamins that their bodies cannot make on their own, taurine for example. Cats are unable to digest plant-based foods the way that people are, so they are not getting many nutrients from these types of foods. They also do not have the digestive system to digest carbohydrates, as in the wild the only carbs they are getting come from what their prey has already broken down. The difference between omnivores or herbivores and carnivores is that their digestion happens at a much slower rate, so the food they eat spends more time being broken down. Digestion in carnivores happens very quickly, so the food they eat needs to be highly digestible and full of energy and protein.
While there are supplements available, in most cases these will not be enough to make up for your cat not eating any meat. There have been many cases of cats and kittens coming into veterinary clinics extremely weak and malnourished because they weren’t receiving the necessary nutrients from a vegetarian or vegan diet. All pets should be eating biologically appropriate diet, even if it is not the same diet that you want or eat. As an owner, if you really can’t live with a pet that needs to eat meat, then it would be a good idea to consider getting a rabbit or other herbivorous pet.