"Fox, a lacto-ovo vegetarian who feeds his dogs an omnivorous diet prepared at home, says the best approach for dogs -- and humans -- is a varied diet from organic ingredients. He says some adult dogs do adapt and even thrive on well-balanced vegan diets, but contends that dogs do best with a variety of foods that include some animals fats and protein.
"Dogs have evolved to a degree, but they've been with us 45,000 years as camp followers, scavengers, village dogs in the third-world countries and they'll eat just about anything," he says, adding that dogs could benefit from a vegan meal at least once a week to detox.
"But then again, we don't have the real science to back up whether it's safe enough, so, for dogs' sake, we need to adopt the cautionary principle."
The first thing doctors tend to ask is why someone is considering a vegan diet, Fox says. In most cases, personal ethics are the primary motivator, followed by food allergies.
In the latter category, a vegan diet can bring relief, veterinarian Armaiti May says."