Asked by: Josie Lott, london
It’s theoretically possible for dogs, but difficult in practice.
Dogs have co-existed with humans for at least 14,000 years and have evolved some extra digestive enzymes that help them to digest plant starches, probably as a result of sharing our food. But a 2015 study at the University of California, Davis, found that 25 per cent of commercial vegetarian dog foods lacked the right balance of essential amino acids. And homemade diets are even worse: a 1998 study found that 50 per cent of dogs fed homemade vegetarian or vegan food had dietary deficiencies.
For cats, it is even harder to balance. Cats are entirely carnivorous in the wild, and there are several amino acids only found in meat, such as taurine, that they can’t synthesise or store, so a vegan cat diet has to be very carefully tailored to their age and body weight.
Too little taurine can cause blindness and heart failure, while too much can lead to serious urinary tract infections. Carnivorous cats absorb all the taurine they need from meat, but synthetic taurine added to vegan food comes in several different forms, which are absorbed by the cat’s metabolism at different rates. This makes it extremely difficult to give cats a balanced vegan diet.