Last month, McDonald’s devised a plan to wedge itself into the dense flow of self-promotion and micro-conversations that constitute Twitter. The fast-food giant had hoped to introduce some of the real-life farmers and producers who supply McDonald’s with potatoes, beef and other products under the organizing hashtags of #MeetTheFarmers and #McDStories.

But within the hour, the company had a social-media disaster on its hands. Tweeters quickly hijacked the #McDStories hashtag to offer their own anecdotes and propaganda, some of it attacking McDonald’s long history of selling cheap meat to Americans, millions of patties and nuggets a day.

One person, under the Twitter handle @MichelleVegan, wrote, “McDonalds scalds baby chicks alive for nuggets.” The Twitter feed for Vegan.com chimed in: “My memories of walking into a McDonald’s: the sensory experience of inhaling deeply from a freshly-opened can of dog food.” Then, of course, PETA entered the fray with a photo of a coil of pink goop, implying that McNuggets were made from “mechanically separated chicken,” an allegation that McDonald’s immediately denied.

Regardless of the veracity of those claims, the episode underscored a new truth: Meat eating is not the simple pleasure it was in previous generations, and not just for those frequenting fast-food joints.

Even as millions of Americans continue to gobble down gourmet burgers, dry-aged steaks, chef-driven charcuterie and bacon-wrapped everything, they’re regularly forced to consider the potential consequences of their actions. Environmentalists want us to think about the greenhouse gases that meat production creates. Humane advocates want us to consider the suffering of animals. Doctors want us to ponder the health implications. And the medical community would like us to understand the potential fallout — otherwise known as antibiotic resistance — of pumping farm animals full of drugs.

(Dan Page for The Washington Post)

It’s as if America has become schizophrenic about meat: As the reasons to reduce or eliminate meat consumption increase, so do the sources of particularly tasty morsels of animal flesh.

Washington is the prime example. In recent years, the Expense-Account Steakhouse Capital of America has practically become the center of the burger universe. We can secure a premium patty in countless outlets, including Shake Shack, Elevation Burger, Good Stuff Eatery, Ray’s Hell-Burger, Big Buns Gourmet Grill, Thunder Burger & Bar and BGR: The Burger Joint. Shall we count the number of barbecue outlets that have opened in the past few years, too? Does this sound like a sign that Washington, home to some of the most well-educated people in the country, has absorbed the message on meat eating?

“We’re schizoid, as a culture, on meat eating,” notes writer Michael Pollan, who has grappled with this own internal conflicts on the consumption of animal flesh. “We love the taste and what having lots of meat has always signified — status, wealth — but at the same time it’s hard to overlook the high cost of meat-eating: to the environment, to the workers, to the animals and to our own health. It’s no wonder we’d be conflicted.”

It’s perhaps not surprising that we’ve reached this point at which meat eating has become almost as polarizing as religion. Groups such as PETA, Compassion Over Killing and Physicians Committee for Responsible Medicine have been promoting vegetarian or vegan diets for years, if not decades. An entire generation of eaters, many of them Twitter-savvy, has grown up with the idea that not eating meat is better for them and the world they live in.

What’s more, some of those groups have been targeting kids almost from the moment they started to make decisions about their diets. People such as Neal Barnard, a physician and president of the PCRM, make no apologies for it. He compares current anti-meat campaigns to those that discourage underage smoking: It’s important to hit ’em while they’re young.

“If a kid, like me, found a pack of cigarettes when he was 11,” Barnard says, “that kid is more likely to grow up as a smoker as opposed to a kid who never encountered them at all.”

Hitting the youth market

PETA, in particular, has actively targeted young eaters with its Peta2.com Web site, which launched in 2002 and has more than 500,000 e-news subscribers. The site has little interest in promoting the health-care savings or potential long-term health benefits of a vegetarian diet. Instead, it adopts a pop-culture approach to make meat-free eating seem cool and “cruelty-free” to animals — or, at the very least, contrarian to the adult world, which in itself might appeal to the more rebellious.

The idea, says Dan Mathews, senior vice president of campaigns for PETA, is not to take an elevated intellectual approach in trying to appeal to youth, but to play up factors important to young eaters. Like looking good, or sex, or celebrities. PETA even works with television producers to insert anti-meat messages into various programs, such as an episode of last season’s “Real Housewives of Miami” in which Lea Black annoys her fellow South Beach sun-bunnies by pooh-poohing a pig roast.

“Being realistic, we realized we had to go to a lower common denominator” to hit the youth market, says Mathews. “They want to look good. They don’t care about something that will take decades to affect them,” like heart disease.

But the anti-meat and reduced-meat messages are not coming just from animal-rights organizations with an agenda. Cookbook authors, activists and even the federal government have embraced an idea that might have seemed radical a generation or two ago: We don’t need to eat as much meat as we used to.

Pollan, in his “In Defense of Food” (Penguin, 2008), famously wrote that we should “Eat food. Not too much. Mostly plants.” The following year, author Mark Bittman espoused essentially the same idea in “Food Matters” (Simon & Schuster, 2009) by noting that we should “eat less meat and junk food, eat more vegetables and whole grains.”

More than two years later, the U.S. Department of Agriculture and the U.S. Department of Health and Human Services issued the Dietary Guidelines for Americans, which recommended that we “reduce the intake of calories from solid fats.” Translation: Eat less meat.

It’s not easy to quantify how those messages have influenced meat eating in the United States. According to a poll conducted last year by Harris Interactive for the Vegetarian Resource Group, about 5 percent of Americans identified themselves as vegetarian, and another 33 percent are “eating vegetarian meals a significant amount of the time.” In 1994, a poll conducted for the Vegetarian Resource Group led the organization to estimate that “0.3 to 1 percent of the population is vegetarian.”

Perhaps more telling are numbers culled by the America Meat Institute from Agriculture Department data. They show that consumption of red meat is down across the board. Americans, for example, ate 56.9 pounds of beef per capita in 2010, compared with 62.4 pounds in 2005. Our pork consumption per person also dropped, from 46.5 pounds in 2005 to 44.8 in 2010. Even our taste for chicken has dulled: We ate 55.5 pounds of chicken per person in 2010, off from 60.5 pounds five years earlier.

The numbers might trend toward a vegetarian lifestyle, but the fact is, Americans still down an estimated one-sixth of the meat eaten in the world. Where does this drive come from? (Aside from the intoxicating scent of those burgers sizzling on the grill at Ray’s?)

Barnard of the PCRM suggests in his book “Breaking the Food Seduction” (St. Martin’s, 2003) that meat eating has an addictive quality. “Scientific tests suggest that meat has subtle drug-like qualities, just as sugar, chocolate, and cheese do,” Barnard writes. “When researchers use the drug naloxone to block opiate receptors in volunteers, meat loses much of its appeal.”

New York University professor and noted nutritionist Marion Nestle says the addiction theory is bunk.

“Humans are omnivores and lots of animals eat meat,” she wrote via e-mail. “People eat because they have to (a drive). Taste drives food choices. We get nutrients (Vitamin B12, among others) from meat and dairy foods that we can’t get enough of from vegetable sources. Our ancestors had no choice. Survival depended on eating meat. We do have a choice, and people and the planet would be healthier if we ate less meat, but I wouldn’t call meat-eating an addiction.”

Whether its product is addictive or not, the meat industry is not sitting back idly and watching America transform into Veg Nation. The American Meat Institute, a trade association that represents red meat and turkey processors, launched a Web site about a year ago called Meat MythCrushers with the idea that it would counter many of the arguments against meat eating. Via studies and video interviews with industry experts, the site tackles what it says are “myths,” such as the belief that antibiotic use in livestock production contributes to antibiotic resistance in humans, or that there’s a concrete connection between meat eating and heart disease.

Janet M. Riley, senior vice president of public affairs for the AMI, acknowledges that lower consumption rates and increased attacks on meat eating led the organization to create the site. But she also says the statistics showing declining meat-eating are deceptive: Between higher meat prices and the poor economy, Americans have naturally started to eat less meat.

On the defense

The videos on the site were particularly important to Riley, who serves as the interviewer in each. She says she wanted to humanize an industry that has become increasingly viewed as cold and mechanical via films such as “Food, Inc.” and books such as Eric Schlosser’s “Fast Food Nation.” When people visit processing plants these days, she says, they’re surprised by the improvements in animal welfare and safety.

That statement might come as a surprise to PETA’s Mathews, who notes that the agriculture industry continues to try to push bills through state legislatures to prevent undercover videos and photographs at slaughterhouses and other facilities, which could potentially turn off more meat eaters. “They’re very threatened,” Mathews says. “This is why they got these bills sponsored.”

It would seem clear, whether it’s McDonald’s on Twitter or slaughterhouses in Iowa, that meat producers, retailers and eaters have assumed a defensive position. Will some of those defenses eventually crumble under more pressure to decrease meat consumption? One former hard-core meat eater found she could no longer justify her habits after doing pro-bono legal work for the Humane Society of the United States and its anti-puppy-mill campaign.

One day, more than three years ago, antitrust lawyer Amber McDonald of the District “made the connection that industrialized agriculture is run a lot like a puppy mill.” She gradually weaned herself from meat and dairy products, a move that came as a shock to her friends, colleagues and family. McDonald grew up in Wisconsin, eating brats and cheese. She used to judge people who ate fish in a steakhouse as not aggressive enough for employment in the legal profession. She laughs at the memory of it now.

Four years ago, McDonald might have been a happy participant in the eight-day barbecue orgy known as Meat Week. But this year, for the third consecutive year, she was organizing her own little counterproposal: Meat-Free Week, which ended Monday. She’s the founder of the event. Is she also a harbinger of things to come in America?