Paleo, vegan, gluten-free: Owners are putting animals on human regimens and fueling a huge pet-wellness industry. But some health experts are concerned. There are pets on raw-food diets, gluten-free diets, grain-free diets, vegan and vegetarian diets. There are pets that munch on treats flavored like a turmeric latte or made with CBD, pets that never skip a probiotic or vitamin C supplement. Some owners whip up special menus at home, while others shop for the growing number of products tailored to these diets. There are no clear or simple rules for how to feed a pet. The U.S. Food and Drug Administration has cautioned about certain animal diets and regulates how pet food is manufactured and labeled, but offers much vaguer guidance on the ingredients. Veterinarians have differing opinions, and scientific research on pet health lags behind studies on humans. The internet is brimming with advice, and misinformation. It’s primarily up to owners to decide whom to trust.