From TIME: "Return of the Meat-Eaters: Many Lapsed Vegetarians Become 'Ethical Omnivores'":

In 2005, a CBS News study found that ex-vegetarians outnumber current vegetarians by a ratio of three to one, suggesting that 75% of vegetarians lapse. A survey by Hal Herzog and Morgan Childers found that these born-again omnivores were mostly women (as many vegetarians are) an average age of 28 years old and had been vegetarians for nine years when they reverted. The majority went vegetarian due to concerns about the treatment of animals and returned to meat because of declining health ("I will take a dead cow over anemia any time," one man told Psychology Today), logistical hassles, social stigmas, and meat cravings. Only two of the seventy-seven former vegetarians surveyed resumed meat-eating because their moral views changed.

For some, like Berlin Reed, 29, the return to meat has ironically been a humane one. Reed, who went vegetarian at age 12, was such a die-hard that his friends once staged a "bacon intervention." He has the world "vegan" tattooed on his neck. But these days, he both eats meat and works with it, calling himself "the ethical butcher." He insists that changes in the butchery profession are crucial to improving the meat system. "I don't eat beef from factory farms for many of the same reasons I won't buy clothes from The Gap," Reed told the Today show. "It's all about the industries and practices that are polluting our world, not whether or not it is okay to kill for food."

Indeed, it seems that the latest form of animal activism is not not eating meat, but rather only eating ethical, sustainable meat. What's that? It depends on the perspective, though it can include some combination or permutation of industry terms like "organic" "free-range," "cruelty-free," and "natural," and labels about animal welfare from certification companies. Sustainable meat-eating is particularly suitable for those who return to omnivorism because of health problems, like nutritionist Julie Daniluk, 38, who co-hosts a cooking show on the Oprah Winfrey Network, where she promotes conscientious meat-eating and weekly "vegetarian days."