This is how Americans talk about food: as sinful or guilt-free, decadent or wholesome, artificial or pure. Natural and unnatural. Good and bad. The modern American terminology around nutrition, says Alan Levinovitz, AM’07, PhD’12, is often more philosophical and religious than scientific. And our dietary credos—Atkins, paleo, gluten-free, low salt, no fat, macrobiotic, raw—can function like faiths, preaching dogma, promising redemption, requiring devotion.

Which explains how Levinovitz, a Divinity School alumnus who teaches philosophy and religion at James Madison University in Virginia, came to write a book on food. In The Gluten Lie (Regan Arts, 2015), he explores why so much fear and moralizing surrounds nutrition, why we tend to demonize certain foods and deify others. Combing through decades and centuries, he unearths the social, cultural, and scientific—or pseudoscientific—histories of contemporary eating taboos.

In the United States, these taboos are partly the inheritance of our Puritan founding. For instance: sugar. “We eat too much sugar, period,” he says. “But is sugar uniquely evil? We’ve said so, shockingly, for the last 200, 300 years.” Long before obesity or diabetes entered the popular lexicon, refined sugar was already under suspicion. In the 1700s, it was guilty because pleasure was sinful. Later, temperance advocates argued that sugar would lead to alcoholism and sexual promiscuity. “They were afraid women and children would engage in what they called the ‘solitary vice’ if they ate too much sugar,” Levinovitz says.

Meanwhile, Levinovitz notes, honey and fruit have enjoyed a “halo” of healthfulness and natural simplicity—unprocessed, unrefined. In his 1852 Comparative Physiognomy, physician James Redfield labeled animals that eat honey as courageous and careful—the honeybee, the hummingbird, and the bear—while the fly and the ant, which eat sugar, were unvirtuous in Redfield’s telling. That dichotomy remains ingrained to this day, Levinovitz writes, even though honey is higher in fructose than high-fructose corn syrup. And despite the fact that, as one endocrinologist and diabetes expert told Levinovitz, the only definitively established metabolic difference between fruit and candy is that “it’s a lot easier to eat tons of candy than it is to eat tons of apples.”

A Stanford undergrad, Levinovitz went to college intending to become a bioethicist. “I realized what I was really interested in was ethics,” he says. “And then I realized that I was really interested in the way stories play a role in ethics.” In his philosophy classes, arguments rested on logic and evidence; in his religion classes, “you could use a story to make an argument.”

Levinovitz followed up with a PhD in the Divinity School’s religion and literature program, focusing on Chinese texts and studying the role that stories and narratives play in the formation of “beliefs that are sacred to human beings.” He found himself asking questions like: What’s the difference between telling a story and making an argument? Or giving a command? “Those are different genres we use to make a public or a person believe something,” he says. “I’m fascinated by the ways those genres are mutually interdependent on a cultural level, and how we ought to think about them when we’re communicating truths, scientific or otherwise.”

He stumbled on a concrete connection between his religion research and food while studying in China in the early 2000s. Back then many Americans were assiduously avoiding monosodium glutamate, believing it caused migraines, irritable bowel syndrome, joint pain, chronic disease, and a swarm of other maladies. Chinese restaurants in the United States posted signs promising “No MSG.” But in China, Levinovitz discovered, MSG—or weijing (“flavor essence”)—was everywhere, and the locals weren’t worried. Over there, he writes, MSG was “a sodium salt first extracted from seaweed by Japanese scientists in 1908, and a staple seasoning in the cuisine of long-lived East Asians.”

In the book, Levinovitz traces the history of America’s MSG scare: its origins in a 1968 letter in the New England Journal of Medicine titled “Chinese-Restaurant Syndrome,” the ensuing decades of snowballing fear, the repeated debunkings, and finally the present-day consensus among food allergy experts that no such syndrome really exists. Yet the belief in MSG sensitivity lives on. Why? The answer is complicated, Levinovitz says, but partly it has to do with a “common and convincing myth” that helped popularize it in the first place: “The products of technology and modernity are inherently dangerous.”

A version of that myth is what underlies food regimens like the paleolithic diet, which promise a return to a past human paradise—if not the Garden of Eden, then a prehistoric evolutionary Elysium. Another iteration of the myth, Levinovitz writes, is “the argument from antiquity,” which romanticizes wisdom from the ancient past—often the ancient Far East—and mines it for modern-day truths. Yet another version: the myth of the noble savage. The 1977 salt guidelines issued by the US Senate Select Committee were largely inspired, Levinovitz writes, by one scientist’s belief that ancient peoples uncorrupted by civilization kept their hearts healthy with a low-salt diet.

But people need stories and myths. Narratives shape our existence and can’t help but inform our decisions. “We tell ourselves stories in order to live,” Joan Didion wrote, and Levinovitz has spent his academic career plumbing the reality of that statement. “We’re very convinced that if we just show people the truth, if we just show people facts, they’ll believe it,” he says. “That’s not true, right? Those facts end up getting conveyed in narrative form.” And people tend to fit the evidence they’re seeing to stories they already believe.

That’s true when it comes to food. Science gets wrapped around preexisting beliefs and seen through the lens of long-standing religious and moral ideas. In contemporary fears about genetically modified foods (GMOs), Levinovitz sees a biblical story of good and evil, in which agribusiness behemoth Monsanto is the devil and those who fight it are righteous crusaders. “Why are people wary of GMOs?” Levinovitz asks. “Why are people scared of vaccines? Why are people excited about artificial intelligence? All these questions I think can be nuanced by looking at the stories we tell.”

Biblical, puritanical thinking also explains the absolutist approach of many contemporary diets. The idea is, if something is unhealthy enough—impure enough—to be curtailed, then wouldn’t it be even better to avoid it altogether? “The government will say, ‘We never told people not to eat fat,’” Levinovitz says. “But any humanist, anyone who understands rhetoric, will say, ‘Well, there’s this danger: if you tell people to limit something, they’ll think it’s bad and unclean, and they’ll cut it out.’”

As a solution, Levinovitz advocates an approach to reporting science that takes lessons from the humanities into account. “Scientists need to be able to point out when we’re using a narrative to get away from science,” he says. They need to be able to recontextualize and communicate information using equally compelling, and more accurate, narratives. “Science needs to recognize the importance of stories in communicating a truth to people. There’s no such thing as a naked fact, really.”