A growing number of people are advocating for vegan diets for their pets for ethical, environmental and health reasons.

“I live with two vegan dogs and a vegan cat. We like to feed our animals without exploiting other animals,” said Matt Johnson, a California-based vegan activist.

In many cases, the decision to switch meat-loving pets to a vegan diet is made because of the owner’s ethical preferences. Most pet foods are made with byproducts from factory farms, so switching to vegan alternatives is a way to avoid subsidising the industry.

“If you run a vegan household it’s a bit like a kosher household,” said Myron Lyskanycz, the CEO of the Florida-based Halo Pets, which makes a brand of vegan dog food. “You don’t want to contaminate your house with meat-based products.”

Lyskanycz has seen a surge of interest in Halo’s vegan range, which swaps meat for chickpeas, peas, oats and vegetables. “It’s our fastest growing product in the company,” he said.

Lindsay Rubin from the San Francisco vegan dog food company V-Dog has seen similar growth, particularly in California, New York and Portland – American cities where there are large human vegan populations.

“In the pet food industry, trends for pets follow trends for humans,” she said. “We want them to be healthy and contribute less to environmental degradation.”

Veganism among humans is certainly on the rise. According to one 2017 report, 6% of US consumers claim to eat a plant-based diet – a 600% increase since 2014 – while another indicated that a third of Americans are cutting back on meat consumption through celebrity-backed initiatives like Veganuary and meat-free Mondays.

“In the last 10 to 15 years, we’ve seen people become very interested in where ingredients come from and how they are sourced,” said Lyskanycz.

This combines with a trend Lyskanycz refers to as “the humanisation of pets”, which is particularly prevalent among millennials, who have become the largest cohort of pet parents in the United States.

“People used to get married, buy a house, have a baby and then get a dog or cat. Now we are seeing couples are getting pets before having a baby. They are treating that animal like a starter baby and looking to feed it with that same care and thoughtfulness,” he said.

Other owners make the switch not for ethical reasons but for health reasons, such as allergies.

“When you are food-allergic as a dog, it’s usually a protein trigger,” said Jean Greek, a Santa Barbara-based veterinarian who feeds her two pit bulls a vegan diet.

A way to alleviate the itchy skin caused by allergies is to identify a protein that the dog has had no previous exposure to. In some cases this means trading chicken or beef for duck or venison, but in others a vegan diet is the preferred option.

But despite her enthusiasm for vegan dog food, Greek won’t advise owners to feed their cats a vegan diet. Dogs, like humans, are omnivores, meaning they can more easily adapt to a carefully planned plant-based diet. Cats, on the other hand, are obligate carnivores, which means their bodies are designed to run on meat.

“The primary concern [of feeding a cat vegan food] is they would experience muscle wasting because they are missing some amino acids. One of the muscles that would get weakened is the heart, so potentially you could have a cardiac arrest,” said Greek.

The question over whether cats can thrive on a vegan diet is hotly debated. While most veterinarians agree with Greek, some, like Armaiti May, believe that with careful supplementation and monitoring, cats can get all of the nutrients they need from plant-based foods.

“They can do well but you need to make sure they have taurine [an amino acid that’s essential for vision] and monitor their urinary tract health,” said May.

That hasn’t stopped thousands of people switching their cats to plant-based diets and swapping tips on Facebook groups such as Vegan Cats, which has almost 7,000 members.

“Even if there’s a certain degree of compromising the animal’s happiness or health, that’s a difficult choice but we should also consider the happiness and health of other animals out there,” said Johnson. “We should be willing to make sacrifices.”

