The Gluten Lie small
There are few aspects of daily existence, particularly in modern society, that are more pervasive than advice on what we should eat. Everyone, including friends, family, strangers on Twitter and self-proclaimed experts in nutrition and health, seems to have an opinion on how to eat in order to improve and prolong our lives. Even legitimate organizations dedicated to the health and well-being of the population add to the cacophony of recommendations on diet.

Readers of Science-Based Medicine should be well aware of the current popularity of avoiding gluten, even absent the diagnosis of celiac disease or thoughtful evaluation for another related condition. Gluten, we are told by gurus and authors of books like Wheat Belly and Grain Brain, is the one true cause of a host of medical complaints, even autism. Avoid gluten at all costs, they say, and watch the pounds melt away or experience the clearing of your “brain fog.”

The resulting glut of glutenless products on the market may benefit the 1% of the population with celiac disease, or help to ease symptoms of the small percentage of people that may be intolerant, but it also helps to further solidify the beliefs of the millions of fad dieters. In the process, pocketbooks are emptied and unhealthy dietary restrictions are encouraged. And rogue gluten-free dieting may actually delay the diagnosis in actual celiac disease sufferers.

Other dietary concerns predate the current gluten-free trend, sometimes by many centuries, and have come to incorporate the language of science, the better to fool us with. Too much fat will kill us with cardiovascular disease. Excess salt will raise our blood pressure and lead to strokes. Added sugar is toxic and the root of our obesity and diabetes epidemics. These are the recommendations that are handed down, often with absolute certainty. They are the mantras that many of us live by without really knowing why.

In his book, The Gluten Lie: And Other Myths About What You Eat, Alan Levinovitz attempts to point out the elephant in the room. What if, as Levinovitz claims, there is a great deal more uncertainty than we are lead to believe? As a scholar of philosophy and religion, an expert in discovering and understanding the common threads that connect seemingly disparate beliefs, Levinovitz argues that many claims about the right way to eat are more religious in nature than scientific, even if the language used to promote a particular claim has evolved.

History is a wheel

Levinovitz first illustrates his overarching theme, that the history of demonizing certain foods is a wheel, with the story of MSG. Beginning in the late 1960s, the common flavoring agent quickly became targeted as a cause of migraine headaches as well as a number of additional symptoms, even severe neurological disease, based on a simple letter to the editor of the New England Journal of Medicine. Widespread public acceptance based on flimsy evidence led to public outrage and MSG became demonized to the point that “No MSG” was soon emblazoned on restaurant signs and menus all over the country. Public pressure even led to the removal of MSG from baby foods, further cementing its toxic status in the lay mind.

In the medical community, we now know that so-called “Chinese-Restaurant Syndrome” is a fiction. Unfortunately belief in the toxic effects of the chemical remain fairly widespread, even if they are dwarfed by the current gluten-free fad. And, as Levinovitz discusses in his book, the psychological pitfalls that resulted in MSG fears are the same.

Although the book is focused on dietary demons, it is the discussion of how our thinking goes wrong where Levinovitz truly shines. As I read the book, and the information revealed by numerous leading experts in the nutrition science, I certainly learned a great deal about the reality behind the science of food fears. But I learned even more about their history and scientific skepticism in general. Although not marketed as such, I found this book to be an excellent primer on critical thinking.

Why did people come to believe that MSG or gluten were the cause of their complaints? Levinovitz, with wit and the occasional laugh out loud snark, discusses the common pitfalls that readers of SBM should be familiar with. As humans, we are terrible at evaluating causal relationships. We are prey to a variety of placebo and nocebo affects. Our memories are highly unreliable. Confirmation bias and the avoidance of cognitive dissonance are powerful forces in all of our lives.

And once a self-diagnosis is made, we are amazingly resistant to questioning it, likely because of the societal stigma against a psychological origin for symptoms. Levinovitz convincingly argues that these same pitfalls are behind a great deal of the current gluten-free trend. He also discusses a variety of powerful archetypal myths that influence our individual food choices and likely bias our attempts at studying them in populations. The ability to deceive ourselves appears to know no limits as even well-meaning scientists without an apparent agenda are at risk.

Nutrition myths

To an author like Levinovitz, who has spent countless hours working to understand the meaning and significance behind the religious narratives passed down over time, dietary claims demonstrate an uncanny similarity. He even compares them to how flood myths have recurred in a variety of cultures. He attempts to understand them in a historical context, ultimately raising serious concerns about their veracity. He wonders if our acceptance of many of them are akin to reading flood myths like a weather report rather than as a metaphor for cleansing and divine punishment.

Think that “going paleo” represents a new approach to choosing what to eat? Think again. Probably the most important archetypal myth that influences our beliefs about food is that of the paradise past. Levinovitz traces the rejection of modern culture and technology back to a group of Daoist monks who rejected grains, believing them to be the one true cause of disease and death two thousand years ago. As Chinese culture changed, and grains became less of a symbol of their civilization, so did the focus of those rejecting modernity. In later generations, the Daoist monks turned their ire on meat and blood, serving as an example of how the rejection of the status quo in favor of the good old days, rather than a specific food, is truly at the core of many of our food fears.

Another archetypal food myth involves the assigning of moral and religious qualifiers to our food. We think of foods as “good” or “bad,” “sinful” or “natural.” These designations don’t actually mean anything however. Rather than science, their origins are often found in religion or in the random notion that if it tastes good it must be bad for you. And once established they perpetuate, becoming part of the underlying fabric of a culture. People come to express dogmatic acceptance without knowing exactly why. Processed food is evil…just because it is. Natural is better…because Adam and Eve didn’t have MS?

Sugar is the most blatant victim of the moralization of food. In addition to concerns regarding weight gain and associated medical problems, historically sugar has been blamed for everything from scurvy and “weak nerves” to ill-behaved children and even insatiable sexual desire. And despite all evidence and understanding of addiction, some anti-sugar proponents have even likened it to nicotine and cocaine, claiming that there is no safe level of consumption.

In the chapter on sugar, Levinovitz introduces two important concepts that have contributed to the belief that sugar is toxic. Monotonic thinking is common in the public. This occurs when we have a hard time accepting that something that is unsafe or unhealthy in large amounts can be fine, perhaps even healthy, in small amounts. A classic example would be red wine. Although the jury is still out on the benefits of moderate alcohol consumption, it is clearly the case that a glass a day is not equivalent in any way to being an alcoholic. The poison, after all, is in the dose.

The second concept is that of “white-hat bias.” This can occur when we investigate and interpret data involving claims that are seen as righteous. It serves to bias us against things we perceive as bad and for things seen as good or virtuous, exaggerating findings that fit into that world view.

In his chapter on the demonization of dietary fat, Levinovitz discusses the concept of “sympathetic magic.” One of the most primitive and widespread examples of magical thinking, sympathetic magic is the force behind, among numerous examples still prevalent today, the belief that ingesting tiger penis can impart virility in a man. Or that drinking beet juice might restore the blood. It also informs the archetypal food myth that you are what you eat.

If you eat animal fat, you will become fat. If you eat lean, you will be lean. At least that was the medical advice given by the Greek physician Galen to his patients almost two millennia ago. Not much seems to have changed since. We are still extremely biased against the consumption of fat such that we think a 47-calorie candy bar will cause more weight gain than an almost 600-calorie binge at an all-you-can-eat buffet of veggies and low-fat cheese. The low-fat label on products, for another example, gives them a so-called “health halo” that isn’t explained by the very unclear science on the subject.

Conclusion: A compelling destruction of food myths

This is a good book and I highly recommend it. In keeping with the tenets of science-based medicine, where prior plausibility and basic science are considered in the evaluation of causal claims, Levinovitz lays a compelling deconstruction of a variety of food myths. The fact that the beliefs at the root of why we fear gluten, fat, salt and sugar are centuries old does not disprove the current popular trends in their consumption. It doesn’t mean that all proponents of their proscription to varying degrees are hopelessly biased and making inappropriate recommendation. But the bar for acceptance must be set higher because of it.

Currently, as detailed in The Gluten Lie, the evidence regarding our diets is almost always less clear than we are led to believe. The study of nutrition is extremely challenging and the difficulty in designing and carrying out research that might more definitively answer these questions is understandable. But, as Levinovitz states, the problem isn’t really with the science. We know that science is a process that can take time to hone in on the right answer. The problem is with the overstatement of our understanding based on what we currently do know. An exaggeration, a half-truth, is still a lie.

Posted by Clay Jones

Clay Jones, M.D. is a pediatrician and a regular contributor to the Science-Based Medicine blog. He primarily cares for healthy newborns and hospitalized children, and devotes his full time to educating pediatric residents and medical students. Dr. Jones first became aware of and interested in the incursion of pseudoscience into his chosen profession while completing his pediatric residency at Vanderbilt Children’s Hospital a decade ago. He has since focused his efforts on teaching the application of critical thinking and scientific skepticism to the practice of pediatric medicine. Dr. Jones has no conflicts of interest to disclose and no ties to the pharmaceutical industry. He can be found on Twitter as @SBMPediatrics and is the co-host of The Prism Podcast with fellow SBM contributor Grant Ritchey. The comments expressed by Dr. Jones are his own and do not represent the views or opinions of Newton-Wellesley Hospital or its administration.