Foods are either natural or unnatural. They are good or bad. Bad foods harm you, and good foods cleanse you. Bad foods are sinfully delicious, or guilty pleasures. Good foods are whole, real, clean, and natural. Bad foods are fake, unnatural, and processed.

The terms we use reflect idiosyncratic dietary faiths, the religion scholar Alan Levinovitz explains in his new book The Gluten Lie, in which he examines why people tend to put moral and religious lenses on food terminology. Much of people's relationships to food can be explained by religious patterns of thought. Our words are often more philosophical than scientific. And our words inform approaches to eating, and overall well-being, in deeply consequential ways.

What happens, then, if you reject these words and frames entirely?

Levinovitz recounts a confrontation at a farmer's market, where he asked a vendor whether her juice was processed. She impressed upon him that processing fruit into juice doesn’t result in processed food, that only corporations are capable of making processed food.

It doesn't surprise me at all that he confronted the juice vendor. He probably laughed out loud, too, and not in a mean-spirited way. Levinovitz—who not long ago took a faculty position at James Madison University, after finishing his doctoral work at the University of Chicago—is a student of logic and argument. He delights in challenging beliefs. And that is what he accomplishes in The Gluten Lie, which dismantles popular arguments for categorically avoiding fat, sugar, salt, and, maybe most contentiously, gluten.

When Levinovitz was studying in China, during the era when everyone in the U.S. was terrified of monosodium glutamate (MSG), he talked to local people who were wholly unconcerned. MSG was everywhere, and it was fine. It was simply, Levinovitz writes in the book, "a sodium salt first extracted from seaweed by Japanese scientists in 1908, and a staple seasoning in the cuisine of long-lived East Asians. But health-conscious Americans knew better." In the states, MSG was an interloper.

Through study of people like Daoist monks who practiced ritualistic avoidance of grains—long before the recent best-selling books Grain Brain and Wheat Belly told fantastical tales of the havoc grains wreak on the body—Levinovitz came to think that maybe we can account for a lot of food beliefs by applying mythical, superstitious patterns of thinking. And it turned out, he was right.

"I was shocked to learn that people thought sugar was bad in the late 1700s," he said, still appearing genuinely shocked as he told me when we met recently in D.C. "Basically as soon as it was introduced, people said it was bad."

Yes, sugar was bad even before diabetes and obesity existed in the average person's mind. The reasoning? Pleasure was sinful. People blamed hypersexuality and alcoholism on sugar. Sugar was foreign, it was associated with savages who eat it; it was bad. According to James Redfield's 1852 book Comparative Physiognomy, animals that eat honey are courageous and careful, like the bee, the hummingbird, and the bear, while those that prefer sugar are not virtuous, like the housefly or "the ant that lives in the sugar bowl." Even though honey is higher in fructose than the high-fructose corn syrup people now love to blame for all of our health problems, honey has long had enjoyed a halo of naturalness. It's the same halo that protects juice but demonizes soda, even though the differences at a macronutrient level are negligible.

A younger Levinovitz initially thought he’d become a bioethicist, but took to religion because of an interest in the way narratives inform beliefs. Philosophy is all about evidence and logic, but then there's religion, where people just tell stories, and that was a way of convincing someone of a worldview. He assumed for a long time, like most people who haven't studied the origins of religious food traditions, that people were taught to avoid pork for rational reasons like outbreaks of Trichinosis, and shellfish because of food spoilage. But that biological theory was rejected by many anthropologists, Levinovitz explains. In the 1960s Mary Douglas wrote a book called Purity and Danger, where she pointed out that most food taboos can't be accounted for by medical concerns. She makes the argument that the foods that were prohibited in Leviticus had to do with animals that cross boundaries. For instance, fish without scales. They were dirty not because there was some plausible biological basis for ingesting shark and getting sick. They were dirty, Levinovitz agrees,  "because they didn't fit into a neat creation scheme.” In other words, they weren't natural.

Pope Francis has embodied this position in his entreaties to respect nature and, at least implicitly, not to genetically modify foods. "This is one of the greatest challenges of our time," he said last year, "to convert ourselves to a type of development that knows how to respect creation.”

He is not at all alone in approaching food production through the romantic lenses of nature and the past. Combine that with basic puritanical fears of pleasure and the monotonic fallacy that if something is impure it must be totally avoided, and almost any popular dietary approach can be explained. Bacon is not kosher, and eating a little bit of bacon is not more kosher than eating a boat full of bacon. This is the way that many people simply choose to treat sugar or gluten: I need to not eat any of these things.

Some people have diabetes mellitus or celiac disease, and they really must avoid these things, or they will become seriously ill. Other people don't have these conditions—or any trace of insulin resistance or non-celiac gluten sensitivity (the significance, definition, and very existence of which is disputed by experts)—but they insist on absolutist attitudes toward things whose effects are clearly dose-dependent.

Wrapping science around beliefs creates arguments like, in the 19th century, that interracial marriage leads to sickly offspring. Now the same logic is used against genetically modified plants. People use biological arguments to justify the same belief that has been around since the beginning of time: New things are unnatural and dangerous. Stuff was better before. We're risk averse and scared of new things. That makes sense from a survival perspective, but it makes for lousy science.

This is the point of The Gluten Lie. I talked more with Levinovitz about the intersection of religious thought and nutrition, storytelling and motivational psychology, and how it all informs faith in science. Here’s our lightly edited conversation.


James Hamblin: You write about the role for storytelling and myth in the world. What's the role of myth in understanding health?

Alan Levinovitz: Myth is great for talking about where everything came from. Or what happens after you die. Or whether there was something before nothing. What is free will? We don't have great scientific accounts for these things. I think there are religious narratives that help people deal with really important but as-yet unanswerable questions. But myth is terrible for dietary rules.

Ideas about religion can be so powerful that people can't endorse them without giving up a part of their identity. It's the same thing with diets. If you've adopted a diet and it's become part of your identity, asking someone to reconsider something as simple as eating sugar or gluten is kind of like asking someone to give up their faith. To admit that the core of their identity is fundamentally mistaken. The pointy-head scientists and the people affiliated with Big Agriculture couldn't possibly be right because they are demons.

Hamblin: The thing I concede to people with things like fad diets is, like a diet where you don't eat yellow things, okay, well you're getting some placebo effect. You're developing a sense of identity and awareness about what you put in your body. So what about the benefits of belief?

Levinovitz: The question I ask, then, is do we have empiric evidence that irrational beliefs about the power of food lead to better real-world outcomes? In other words, I might be convinced that it's worth thinking that gluten causes autism or that Paleolithic dieting is good for you if having those beliefs were genuinely better in terms of outcomes. To take a similar argument with religion: Emile Durkheim, sociologist of religion—he didn't think religion was true. But he thought it was necessary for cultivating ethics. Religion was a sort of belief engine that would keep people good. The argument then is, if we don't have this set of beliefs, how are we going to get along? Why would we treat each other nicely? We'll just dissolve into chaos. Which is not true. We can treat each other just fine without a false belief system that tells us to. I would argue the same thing for living healthfully. There's just no reason to think that quasi-religious beliefs about the miraculous powers of foods, or the demonizing of foods, benefit our health. And if that's the case, then we should work to get rid of them.

And I think it does hurt our health, because we decide on easier things like miracle berries. And we live in fear, because the world is filled with these invisible antagonists of modernity: toxins and chemicals and radio waves. If there's one thing we do know it's that being terrified of life is not good for you.

Hamblin: At least we're not going to war over diets.

Levinovitz: Well, if you look back in history, the first thing leaders do to introduce an us-them dichotomy is introduce dietary rules. It's the best thing: What do we eat? What do they eat?

As for what we eat, I think the USDA and academic nutritionists need to stop coming out with nutritional guidelines. Because it's an extremely fallible science that's constantly contradicting itself, and it makes people think that science is not to be trusted. First they thought this about cholesterol, now they think that? I guess we just can't trust those pointy-head scientists! You can tell people to eat in moderation and get physical activity, and then you don't have to flip-flop on anything. And 99 percent of doctors will agree that the problem is not that people eat in moderation but slightly too much dairy or something.

Hamblin: My sense is that the nutrition guidelines now are more reactive than anything. There are so many people out there who believe that carbs are just bad, for example, that it makes sense to have a confluence of experts going on the record saying  that moderate whole-grain intake is part of a healthy approach to life.

Levinovitz: Rhetorically, though, it's something of a mistake to engage in these arguments to begin with. What enables dietary nonsense is the quibbling about ratios and constructions about kinds of food. So the way to counter dietary nonsense is not by coming up with a new set of more reasonable laws; it's by saying I refuse to even participate in this conversation. We don't even need to think about food this way.

Hamblin: What about people who are eating three meals a day from CVS?

Levinovitz: I know. I go to some stores and see ten flavors of Oreos and I'm like, good God, I clearly don't understand reality.

Hamblin: But I agree that self-correcting science isn’t well received by a lot of people. Like how it’s bad in politics, where you can't "flip flop" on things you've said or advocated. There's some kind of virtue in the political economy to holding one view and never changing it, regardless of situations changing. That makes you a hero. Is that because of the importance we put on faith? In terms of a belief that is unshakably held in the face of evidence to the contrary. Or at least finding ways to fit new information into your worldview without changing your worldview.

Levinovitz: I think the faith you’re describing is a part of overconfident religion. It’s the faith of pseudoscience. We often generalize about religion, but not all religion is incompatible with science. Just look at the Vatican scientists supporting golden rice. You’re talking about a bad faith that you see in religious people and atheists alike, a type of faith that thinks there’s something virtuous about being unshakeable in your opinion.

Hamblin: Well my opinion is that the guidelines are worthwhile and won’t blow up in anyone’s face, if only because this time around they’re especially vague. Opposite that, there are national fitness guidelines, that say everyone should get 150 minutes of exercise every week. I asked one of the people who helped write the recommendation recently, what about 149? And he said, obviously don’t expect a difference. The number 150 is really about behavioral research. You have to give people something concrete and short-term. If you tell them to just be more physically active this year, they won't do it. It's not actionable. So I still retch when I see books  like 10 Days to a Better Butt, but now slightly less. I don't know how many people selling 10-day plans are thinking about motivational psychology as opposed to strategic marketing, but they do have something on their side. It probably works better than something vaguer, like The Better Butt Lifestyle. Or, even safer, The Long, Difficult Road to a "Better" Butt.

Levinovitz: So the current state of the art in motivational psychology is to ask people, what do you want to accomplish for yourself? And then giving them ways to fulfill that goal. Which is very different from national guidelines.

Hamblin: But can't you motivate people by changing priorities and values?

Levinovitz: We just don't know how. And let's not tell noble lies unless we have really good evidence that they're going to work, because they're going to bite us in the ass when we come back and recant. There's so much science that's good. Like vaccines. Why would we undermine the validity of this incredibly beneficial and solidly grounded enterprise through a few unfounded but highly public decrees?

Hamblin: I think a lot of the mixed public messaging comes from the pace of the news cycle. Because on the Internet, no one seems to want to read things that are three days old, and there are a lot of health writers who have to write something every day. In most of the media industry, motivations are not aligned for people to be successful and also to tell entirely accurate, staid stories. Dr. Oz has to talk for an hour every day of the week. What a challenge, to keep so many people constantly tuned in and never get carried away, over thousands of hours of talking.

Levinovitz: It's really important for media to help separate science from corporate interests and debunk bad science. But the problem comes when, in doing that, people associate all science with corporate interests, and they want to hate it all. We have a religious understanding of moral pollution in terms of people who have consulted to corporations. In writing my book, I wanted to talk with biotech people about GMOs, but I was scared that if I even talked with them, I would be seen as tainted. Do we want academia that never talks with industry? It's equally pernicious in understanding how corporations interact with academics and journalists as it is in understanding how foods interact with the body.

Hamblin: So how do you highlight corruption without feeding monotonic mistrust?

Levinovitz: People seem to think that a scientific consensus can be bought by industry. And while the scientific consensus has shifted in nutrition, it's never been bought. The example people always point to is tobacco companies: They bought the scientific consensus, and that's why we can't trust science. The truth is that since the late 1800s scientists have said tobacco is terrible. It wasn't until the 1950s that it was connected to cancer, but scientists knew even before that that smoking blackened the lungs, et cetera. Were doctors influenced by the PR machine in being slow to stop people from smoking? Yes. But no scientific consensus ever said it was okay. The tobacco industry only got to the people who publicly represented the scientists. People need to know they can trust scientific consensus, it is reliable, and it is impossible to buy.

Granting people the ability to believe in quasi-religious narratives about food and medicine will have very real public-health consequences, like the kind we are seeing with the anti-vaccine movement.

Hamblin: I think that there are, broadly, two types of patients: the anxious, not super analytically-minded people who want to hear what's good and bad and just follow what the doctor thinks is best. And the opposite, people who want to know every potential risk and benefit and weigh everything for themselves. Some people handle that well, other people get unduly scared by the smallest risk. So when speaking to a mass audience, how much do you talk about extremely rare failures and adverse effects? When you have to boil it down to a sound bite or tweet, do you just say, vaccinate, it's safe and smart? Because, for some people, that will only feed into a conspiracy theory.

Levinovitz: It's incredibly hard. This is disclosure ethics, listing all of the potential side effects on medicines. Anti-vaccine advocates will say, well look at all of the things that are on the packaging label! Which, to me, is an argument for being paternalistic and removing those things because, is it doing any good? I don't think that it is, on the whole. It's just giving people material to be scared by. At the same time, you have to have transparency. You don't want to encourage a black box of medical knowledge, where no one's disclosing anything. What people are deciding with vaccines is that when there's something so important to public health, we're just going to legislate it. But then people think, Oh no, big government.

Hamblin: Which is most of America. And vaccines are products of the pharmaceutical industry, of which the public is especially wary. So will vaccine legislation pass?

Levinovitz: Yes, but I think it'll take a minor disaster. There will have to be a couple deaths that are so prominent in the public consciousness that people are willing to pass legislation. Which is sad. But thank God we're having measles outbreaks and not polio outbreaks, and that that's what it might take to get people to mandate vaccination. It's like hoping a small island sinks to convince people of the importance of global warming, not waiting until all of California is underwater.

Hamblin: If California were underwater, that would eliminate a lot of the anti-vaccination problem. No, but it's just such an easily politicized conspiracy theory, educated elite doctors telling us one thing but we know better.

Levinovitz: That's the thing with food narratives, and all branches of pseudoscience. Creationism, climate denialism, whatever it is. If you resent pointy-head authority, there are these other areas—Paleo dieting, for example—where there's extremely technical literature that doesn't take long to master but gives you a sort of esoteric expertise that allows you to feel as though you have something that those pointy heads don't. I've seen that a lot within these diet communities: macrobiotic or probiotic, Paleo, they'll say things like, Well, my doctor doesn't even know about the gamma-three globulin protein. She hasn't even looked at the studies about X, Y, or Z Neanderthal. She doesn't even know. And all of a sudden you feel like you have this expertise that other people don't.

Hamblin: Well that's how every conspiracy theory works, right? Along with some realization, some moment of enlightenment?

Levinovitz: Take Gary Taubes, who's a great science writer and skeptic who debunked the dangers of salt really effectively, and the dangers of fat, and then all of a sudden, he became a convert and called sugar toxic. He became the kind of person he'd been criticizing for so long. People can be totally reasonable and also endorse something that is just not.

Hamblin: As a writer it's easy to want to defend positions you've taken even as new evidence and legitimate critiques come along.

Levinovitz: What about people who’ve never been reasonable?

Hamblin: Well when I talked with Vani Hari [The Food Babe], who has been so accused, I got no sense that she’s less than genuinely concerned about everything she tells the public to be concerned about. She’s accused of profiteering, but I think that's simplistically cynical. I don't think many people are legitimately willing to sell their identities—and knowingly do harm to public understanding—solely for money. Maybe I'm wrong.

Hari tends to underestimate the complexity of most of the issues she mobilizes people for/against. But she's great at mobilizing. I hope she'll move into working with good scientists on issues that really need awareness—climate impact of certain foods, human rights issues in agriculture, depletion of bees. I've gotten so into bees lately. You know I used to hate them? Now I love them. Anyway, she and others in her ilk are fundamentally anti-establishment in their messages. So many things are myths that we've been fed. She says the idea that nutrition science is complex is itself a myth that we've been fed.

Levinovitz: And they can end up making more money from fueling paranoia than the people they accuse of selling out to biotech or pharma.

I just don't want people to get caught in this endless cycle of nonsensical dietary practices, in the same way that I wouldn't want people to still be doing exorcisms. But the exorcists are way more exciting than the people who are telling the public that exorcism doesn't work.

The problem is that we just don't know a whole lot beyond eating in moderation, and we can't promise a lot, and there are a lot of limits to medicine. That doesn't sell books. Michael Pollan's rule "Don't eat anything your great-great-great grandmother wouldn't recognize as food"? That's a terrible idea. My grandmother wouldn't eat any international food. Don't eat anything that contains things you can't pronounce?

Hamblin: Ascorbic acid!

Levinovitz: That turns everyone into the Food Babe. "Cook for yourself" is safe, but it's classist. It assumes that you have a stove and the time to cook.

Hamblin: It's not as classist as saying go out to restaurants every night.

Levinovitz: Sure. And I think most people really do have enough time to cook for themselves.

Hamblin: I'm told they do. So what more than that can we actually responsibly recommend to everyone? You write in the book about "eating in the fourth dimension."

Levinovitz: The idea is that three dimensions of food we normally consider are quantity, quality, and type. So, for a month, or however long is tolerable, you eat in the fourth dimension, which is time. You read no nutrition labels, and you “detox” from thinking about food. Instead you think about the time you spend preparing food. You make sure to spend a half hour four nights a week, or whatever, cooking and eating. If people really ate in the fourth dimension, I think we'd be much happier, and healthier, and not as beholden to pseudoscience. I think that would be great.

Look, now I'm an evangelist.