Can cats be vegetarians or vegans? 

With more and more people exploring the benefits of vegetarian and plant-based diets, thoughts are naturally turning to whether it might be possible to extend this type of diet to pets.

While humans can exist perfectly well on a plant-based diet, the same cannot be said for our feline companions. Due to their origins as desert-dwelling hunters, and after many thousands of years existing on a diet of small mammals, cats’ anatomy and metabolism have evolved to digest a purely carnivorous diet.

Why are cats carnivores?

A diet consisting mostly of small prey is higher in fat and protein, and so cat’s digestive systems have developed to process such diets: their gastrointestinal system is comparatively shorter than species which have to digest fibrous plant material.

Cats also do not possess the enzymes needed to produce many essential nutrients themselves and are subsequently a lot less flexible when it comes to the diet they are fed. They need meat in their diet to provide the necessary proteins, vitamins and essential fatty acids.

A plant-based diet is unlikely to be high in fat and may not be as high in protein (and certainly will constitute very different proteins). It is likely to be higher in carbohydrates and for these carbohydrates to be broken down a specific enzyme called amylase is required. In the saliva, the pancreas and the gut, cats have far less amylase than other species (such as humans and dogs). Therefore these diets will be much harder for a cat to digest and extract nutrients from.

Twenty-two different amino acids form the building blocks of all proteins within the body. Essential amino acids are those which an animal cannot synthesise themselves, they have to source them from their diet. There are 11 essential amino acids in cats and one of the most important is called taurine. This amino acid is found exclusively in meat and fish.

What would a veggie diet do to my cat? 

One of the issues with trying to feed a vegetarian or vegan diet to cats is that while humans are able to synthesise taurine from sources other than animal proteins, cats cannot. Without a good supply of taurine and other essential nutrients only found in animal proteins, a cat’s health will start to deteriorate as various parts of the body struggle to function. A taurine deficiency will have serious consequences.

The first area to be affected is the eye – photoreceptor cells in the retina, the area at the back of the eye, require taurine to work correctly, so blindness may be one of the early symptoms of taurine deficiency. The muscle of the heart depends on taurine also, so over time a lack of taurine in the diet will reduce the ability of the heart to pump blood which in time can lead to significant heart disease and in many cases death. Taurine deficiency can also lead to developmental problems in kittens, suppression of the immune system and can also increase the risk of blood clots developing.

What should I feed my cat? 

As taurine deficiency can be so life-threatening it is always important to feed a complete, meat or fish-based cat food. All cat food manufacturers registered with the Pet Food Manufacturers Association will ensure that adequate taurine is present in their complete diets.

Vegan and vegetarian cat owners need not despair at the realisation that cats need to be fed a meat-based diet. By feeding your cat in this way you should not feel you are falling short in your personal beliefs and your quest to do no harm to animals or the environment. On the contrary, by feeding your cat meat, you are providing them with what they have evolved to need to stay healthy and happy, which as pet owners, is our ultimate goal.

For more advice about feeding your cat, visit https://www.cats.org.uk/help-and-advice/diet/diet