Dogs need protein to build muscle and maintain good health. Many believe that a diet of meat and grain is the best option for pets, but did you know that a high-meat diet is a relatively new trend? And it’s not the healthiest one for your pet. Prior to the Industrial Revolution, companion animals ate what humans ate, and meat was a rarity. It wasn’t until the 1850s that pet food became a supermarket staple. Today, dog food is a medley of processed meat from factory farms – animals that are unfit for human consumption end up in your dog’s kibble bowl. According to website Dog Food Advisor, there have been 180 dog food recalls in the past decade, and the major recalls were caused by bacterial contamination from meat. So, what is a healthy diet for dogs? In the digestive process, protein breaks down into amino acids to make hormones, build muscle, and protect your pet from infection. Protein molecules are made by combining a variation of 20 common amino acids, and dogs require 10 amino acids to come from their food. Like humans, their bodies make the rest, including taurine, so long as they have the right building blocks. According to Dr. of Veterinary Medicine Jennifer Coates, this means “that dogs can get all of the amino acids they need while avoiding meat.” A vegan diet can provide the full amino acid profile your dog needs to thrive. Dr. Coates advises a right balance of complementary plant proteins, like beans, soy and whole grains if you want to feed your dog a vegan diet. However, there is another healthful option to consider – the complete protein of fermented yeast. Fermented yeast like Koji, an ingredient revered in Asian cuisine, and Saccharomyces cerevisiae found in nutritional yeast, offer all 10 essential amino acids. This can take the guesswork out of whether your dog is getting the right balance of amino acid building blocks, because all the necessary ones are there. Fungi and other yeasts have high antioxidant content, and nutritional yeast contains alpha-mannans and beta-glucans that have been linked to increased immunity and lowered cholesterol levels. Dogs love the taste of yeast too, it’s used as a flavoring agent in many commercial pet foods on the market. Required amount of protein differs from dog to dog as their size and activity levels are a big factor. Fermented fungi like yeast and koji provide up to 49% protein by weight, while beef only provides 24%. Pet food startup Wild Earth has developed a dog food that uses fermented yeast as a protein source. The process is similar to how beer is brewed, except they use the concentrated yeast and remove the liquid. Growing yeast and turning it into dog food only takes 3 days, compared to the 6 months it takes to unnaturally fatten up a chicken. So not only can your dog thrive eating a plant-based diet, the planet will thrive too.