Dana Hanlon has renounced havarti, Gorgonzola, Port Salut, goat Gouda and brie. She prays that a company will someday develop an opulent fromage that isn’t made of animal by-products.

“I’d be the happiest person that ever lived,” says Hanlon, a personal trainer in Santa Monica, Calif. “There’s really no vegan cheese substitute that isn’t the most disgusting thing you’ve ever tasted.”

To say that Hanlon’s diet is restrictive is to say that Madonna savors a spot of attention. Hanlon began the transition to a vegan lifestyle after eight years as a vegetarian. She is repulsed by factory farming, which she first saw in videos for People for the Ethical Treatment of Animals.

“I made the connection between the hamburger on my plate and the cow being tortured in the barn, so I couldn’t just blindly keep eating meat,” she says.

The decision sometimes interferes with her social life. Once, at a party, she faced off against pot roast with vegetables cooked in the same pan. Hanlon kept quiet (“Nothing kills a party faster than a self-righteous vegetarian,” she says) and imbibed just bread and wine.

Hanlon’s biblical supper of bread and wine illustrates how food, like religion and politics, has become a complex, sometimes taboo subject around the hearth. She is well read, and her concerns for the environment are rooted in research. Increasingly, though, there is a subculture of activists who are “food fundamentalists,” living by codified rules and a restrictive list of what they can eat.

In his book The Gospel of Food: Everything You Think You Know About Food Is Wrong, sociologist Barry Glassner writes about “nutritional imperialists” who decry “bad” fats, fattening carbohydrates and other suboptimal foods, as well as “dietary idealists” who consider social justice issues like the rights of farm workers before eating anything. With moral certainty, these people believe that their way is the right way, says Glassner.

There are also “flexitarians,” semi-vegetarians who occasionally eat meat and animal by-products like butter; “orthorexics” who are obsessed with eating healthy food to the detriment of their health; and “green consumers” who consider the environmental impact of what they consume.

“It’s a form of religion,” says Susie Orbach, the British author of Bodies, which examines the commercialization of the body. For a lot of people, “these different ideologies are about building a fortress or boundary inside of which they feel they can eat right.” A fear of food has infected our culture, explains Orbach, who is renowned for having counseled Princess Diana, and the trend has accelerated over the past 25 years.

Glassner and Orbach blame food marketers, scientists working for diet-food companies, diet-food manufacturers and reporters who write jumbled diet columns that cite conflicting studies, among other culprits. “There are a lot of organizations whose livelihood depends on us being terrified of one food or another and, consequently, buying another kind of food or product to make ourselves healthy and safe,” Glassner says from his office at the University of Southern California in Los Angeles.

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Whether it’s for moral, environmental or health reasons, concern for the afterlife or what might be etched onto our tombstones, society is obsessed with eating right. The latest miracle weight-loss regimens and fad diets are a staple on morning talk shows and in celebrity tabloids.

Gwyneth Paltrow is a macrobiotic devotee who fell off the wagon during her pregnancy because brown rice made her feel nauseated. Designer Donna Karan lost 20 pounds by eating only raw foods; Demi Moore, Woody Harrelson and supermodel Carol Alt are also reported fans of the raw-food movement.

At the Centre for Addiction and Mental Health in Toronto, Christine Courbasson, who treats patients with eating and substance-abuse disorders, says that up to three percent of her clients are raw foodists. “There’s a rigidity in what, when and how they eat, and they won’t change their rules,” she says. “Food has taken over their lives.”

Orbach emphasizes that food activists who devote their lives to saving the environment have merit, and she supports them on a political level—until they become rigid and micromanage every morsel. “When you get paranoid in relation to each individual bite, you know something crazy is going on,” she says.

However, green consumers have scientific evidence to back up their concerns. The environmental impact of factory farming is well documented in a 2006 UN report that concluded that livestock agriculture is responsible for 18 percent of greenhouse gas emissions. This study alarmed Mark Bittman, a food columnist for The New York Times, so much that he changed the way he eats. In his book Food Matters: A Guide to Conscious Eating, he describes his awakening: “Never before had I realized that issues of personal and global health intersected so exquisitely.”

As much as he could, Bittman eliminated junk food, processed food and animal products from his diet. He now eats plant products exclusively until 6 p.m. For dinner, he occasionally has meat, cheese and eggs, and every couple of months he allows himself a cheeseburger, fries and a Coke. His approach is pragmatic: “No food is forbidden. No food is evil.”

Meat hasn’t been on 31-year-old Stefanie Shapiro’s table since she became a vegan at 19. Shapiro graduated with a master’s degree in public health from Harvard University in 2008. “Ideally, I’d love for everyone to be a vegan, but that’s not going to happen in my lifetime,” she says. “The bottom line is that this planet will survive us.” Shapiro occasionally has low energy at certain times of the month. “My body composition and my disposition would do better on a little bit of meat,” she says. Still, she feels healthier being vegan and doesn’t give in to occasional desires because social justice trumps all else.

Social justice is also top of mind for Leslie Garrett, who offers a smart and funny guide to shopping in The Virtuous Consumer. Her book contains tips on creating a simpler, greener lifestyle without clobbering readers with rules or making them feel guilty.

In a phone interview, Garrett described an Earth Day potluck dinner where she’d suggested that guests bring meals made locally. It seemed simple. Instead of an entree, one guest showed up with a wicker basket filled with seeds for the kids to plant. She later confessed to Garrett that she was terrified of bringing “the wrong thing” and told her husband, “I’m afraid I’ll get voted off the island.” This wasn’t judgment day; Garrett just wanted her guests to sample local, organic fare. “Food is many people’s last connection to the natural world, but we’ve lost that sense of pleasure surrounding it,” she says wistfully.

Jessica Acs, owner of Beau Vega catering in Vancouver, specializes in edible pleasures. The gourmet vegan chef experiments with nuts, seeds and fruit pulp to create desserts that don’t taste like ceiling tiles. Acs has mastered a chevre made of macadamia nuts and cheesecakes made of almond cream and coconut oil. “I’m always trying to replicate the flavors and textures of the foods we’re used to eating,” she says.

But Orbach argues that there’s no harm in eating the real thing. “The idea that you won’t let the grape from Chile pass through your mouth because you’ll somehow be tainted with the immorality of capitalist exploitation is too purist,” she says. “We live in a capitalist economy, and that’s not going to change.” It’s the end of her workday in London, and Orbach opens a bottle of St. Peters Best Bitter beer. “I hasten to add that it’s organic,” she deadpans.

Across the English Channel, Bittman is visiting Paris. It’s difficult to avoid meat in the culinary capital of the world, right? Actually, it’s easy, says Bittman. For breakfast, he had chickpea and spinach stew. Since then, he has had peanuts, an artichoke and a banana. He already knows that cheese will be a big player at dinner. “The options are unbelievable,” he says. “What can I tell you? I’m eating cheese every friggin’ night.”

Bittman has found a way to help the planet and have his (real) cheese and eat it too. The rest of us should be so wise.

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The Lexicon

Herbivores, carnivores and omnivores are so old-school. Here are the new labels of choice:

The CHOCOHOLIC has never met a chunk of chocolate unworthy of murdering. (The writer includes herself in this category.)

The DIETARY IDEALIST injects morality into food and weighs social justice issues.

The FLEXITARIAN eats primarily grains, vegetables and fruits but hasn’t ruled out meat, fish, poultry and dairy.

The GREEN CONSUMER considers any environmental impact before consumption.

The LOCAVORE only eats food grown within 100 miles.

The MACROBIOTIC promotes holistic living by eating natural, unrefined foods that are low in saturated fats.

The NUTRITIONAL IMPERIALIST lobbies against bad fats, fattening carbohydrates and other foods considered inferior (like pizza).

The ORGANIC-FOOD DEVOTEE eats food made according to certain production standards (without pesticides, insecticides, herbicides and hormones).

The ORTHOREXIC is obsessed with eating healthy food to the point of ill health.

The PESCATARIAN eats vegetables, fruits, nuts, beans and fish or invertebrate seafood but not mammals or birds.

The RAW FOODIST eats unprocessed and un-cooked plant foods.

The SLOW FOODIST opposes fast food, promotes local and organic farms and encourages ethical buying.

The TRUE FOOD FAN, with a child-like enthusiasm for new things, eats anything and everything from all cultures because eating is one of the great pleasures of life.

The VEGAN lives on vegetables, grains, legumes, fruits, nuts and seeds and avoids animal by-products (including eggs, cheese, milk, butter and honey).

The VEGETARIAN eats fruits, grains, seeds, nuts and occasionally animal products but no meat or fish.