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Wild Findings From an Analysis of 400 Diet Books

Wild Findings From an Analysis of 400 Diet Books

A scholar read 400+ diet books going back to the 1860s. She discovered the real reason why diets become popular—and ultimately fail.

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  • This post, like most posts going forward, contains an audio version (below) and a “short version” of the main idea in each section (for those who prefer to skim).

Onto today’s post: A podcaster recently asked Gwnyeth Paltrow to outline a typical day of her wellness routine.

She said she fasts for 17 hours daily, from 7 pm to 12 pm. Then she eats:

  • Breakfast: Coffee, celery juice, or lemon water
  • Lunch: Bone broth or soup for lunch
  • Dinner: A paleo meal

Her diet went viral, and backlash ensued. Online nutrition influencers picked apart everything wrong with her diet and offered their own solutions. People made jokes at Gwyneth’s expense. Naturally, there was then a backlash to the backlash, with people coming to her defense.

We’re not going to unpack Gwyneth’s diet in this post. We’ll always have a new celebrity, doctor, influencer, nutritionist, thought leader, scientist, user2718437365, etc., who gives us unconventional instructions about what to eat and tells us a story about why it works.

We’ve had these people since the 1800s. It’s far more interesting and informative to explore:

  • Why we search for exactly what to eat in the first place
  • Why we choose the diets we do
  • What that can tell us about making food choices that help us reach health goals

How dieting started

The short version

An obese rich guy in the 1860s created a list of “can eat” and “can’t eat” foods, then wrote what became a bestselling book about it.

The details

About 55 million Americans are on a diet plan, and 50% are trying to lose weight. Diet and weight loss books generated $580 million in sales in 2019.

To understand why and how the diet industry started, we spoke to Adrienne Bitar, Ph.D. She’s a professor at Cornell University, a leading expert on the history and culture of American food and health, and the author of Diet and the Disease of Civilization (a fascinating book!).

She explained that dieting is a very new phenomenon for humans. “To reject food (and go on a diet) is really a privilege,” Bitar said. “For so much of human history, we've just been scraping by.” We ate whatever gave us the most calories at the moment.

Then the Industrial Revolution happened. We started having easier access to food. We also became less active. In turn, people started gaining weight. Obesity first rose among the rich.

Enter a man named William Banting. He was one of those rich people who became obese. To lose weight, he came up with a list of “can eat” and “can’t eat” foods and followed it.

Banting ate only meat, greens, and fruit. He avoided root vegetables, potatoes, butter, milk, pork, salmon, sugar, and beer.

But it worked. He lost 35 pounds. He wrote about it in the first large-scale diet book, published in 1863 and titled Letter on Corpulence, Addressed to the Public. His diet was the first iteration of a low-carb diet.

The book became a bestseller in the US and UK and kickstarted a new diet industry.

Soon, doctors and quacks alike began cranking out diet books. They had fantastic names like “Advice to Stout People” and “Foods for the Fat.”

The diet advice back then was just as varied and even wackier than it is now: chew a bite of food 100 times, drink only vinegar (Lord Byron’s brainchild), ingest tapeworm, take arsenic pills, eat like the Inuits, pray the fat away.

Diet books are now some of the bestselling books of the twentieth and twenty-first centuries.

Why we diet

The short version

A historian analyzed 400 diet books and discovered that stories are what make diets popular. These stories use the “banal, often boring material of breakfast-lunch-dinner and the quest for self-improvement to channel larger concerns about the success or failure of America,” cultural trends, anxieties, and more.

The details

Diet books, of course, sell us a tangible goal. Eat this, not that to lose weight, build muscle, see more of our abs and less of our love handles, detoxify our body, lower our cholesterol, etc.

But that’s just surface-level sales copy. Bitar analyzed 400 diet books going back to the 1800s. She gathered these books from historical archives, online auctions, and garage sales. She even stumbled onto a treasure trove via Craigslist from an old woman who’d been collecting diet books her entire life.

After analyzing all that text, Bitar found that the specific advice on what to eat was “mere details.” That information took up only 20 percent of the copy. The books’ most significant features were the stories about the diet.

Bitar explained, “It can't just be a (list of can and can’t eat foods). A diet has to tell a story about ourselves. It has to pick up on bigger currents in our culture that are prevalent.”

Humans are unique because we can tell stories. Stories helped us become the apex species. They allow us to plan for the future, figure out our place in the world, cooperate, make decisions, and much more. Stories are the ultimate persuasion tools and research from psychologists at Harvard suggests we’re ~20 times more likely to remember information if it’s part of a story.

Diet plans wouldn’t work without stories. They usually tell a “flab to fab” storyline, but the “fab” has less to do with actual weight loss and more to do with getting the life we want but don’t have.

“Diets use the banal, often boring material of breakfast-lunch-dinner and the quest for self-improvement to channel larger concerns about the success or failure of America,” Bitar wrote. “(Diet books) stand in for the bigger debate about history, salvation, nature, money, power, sin, hope, innocence, experience, time, and all the other ideas that make the world worth thinking about.”

“There's this belief of perfectibility,” Bitar told us. “(Diet books tells us) if we just eat the optimal or the best combinations of foods, we’ll be beautiful, fit, lovable, healthy, well, and vibrant.”

We often choose a diet based on our underlying beliefs about society. For example:

  • The detox diet, cleanse diet, etc. These diets were originally inspired by drug and alcohol addiction and ideas of removing environmental pollution. We then applied that philosophy to eliminating the toxins in our own bodies. The underlying idea is that modern food technology has poisoned our biology, and certain foods can restore us to purity.
  • The paleo diet, clean eating, and eating only organic. These diets pull from the classic biblical narrative of Adam and Eve and The Fall. They inspire nostalgia for the simpler times of our ancestors before the world was corrupted by the modernity of taxes, traffic, and Doritos (a utopia that, Bitar said, has scant research to stand on).
  • Biohacking-ish diets like the ketogenic diet, continuous glucose monitors, etc. These diets tell us that by leaning on science and integrating data into what we eat, we’ll be able to surpass our biology and nature and find an optimized state. It’s no wonder these diet methods first became popular in the tech industry.
  • The carnivore diet. This diet leans on a narrative that modern men have become emasculated and that by eating only food we once had to hunt (meat), we’ll be able to reclaim our health and physicality. Unsurprisingly, this diet is most popular among men and pushed by large men living like cavemen.

The truth about diets

The short version

Long-term nutrition success depends on whether or not you can follow a diet for more than a specific time period, like 12 weeks. Your own successful approach to eating probably won’t abide by hyper-specific “eat this, not that” rules—and it won’t fit neatly into a story.

The details

Sadly, humans didn’t come with a manual for the perfect day of eating. Humans are marvelous in that we can eat all kinds of combinations of foods and be healthy. If we couldn’t, we wouldn’t have taken over the world.

And every diet will work to help us reach tangible goals, like weight loss. Until it doesn’t.

As I pointed out in my book The Comfort Crisis, one extensive survey in the UK found that people quit fad diets after 5 weeks, 2 days, and 43 minutes.

My friend Layne Norton recently appeared on the Huberman Lab podcast and explained why. He pointed out that six of every seven obese people have lost a significant amount of body weight. But they didn’t keep it off. Why?

He explained, “People choose a (fad) diet and think, ‘I’m going to lose weight.’ But they do not give any thought to what happens afterward. People will say, ‘I want to do a ketogenic diet because I want to increase my fat oxidation,’ and they’re talking about all these scientific mechanisms and everything (ed’s note: stories!). And that’s great. But can you do (that diet) for the rest of your life? If the answer is no, you need to rethink what your approach is.”

A meta-analysis of 14 different diets found that “diets are all equally terrible for long-term weight loss,” Layne explained. But when the scientists stratified the participants by how closely they followed the diet’s instructions, they found that the most adherent people lost more fat. Regardless of the diet—every diet worked when the study participants followed it long-term.

“So what (this meta-analysis) showed is that we need to ask, ‘What is going to be the easiest diet for you to adhere to in the long term?’ And you should probably do that,” Layne explained.

And that “long-term” question probably won’t abide by hyper-specific “eat this, not that” rules—and it won’t fit neatly into some story about the fall of man or a techno future or masculinity.

How to diet better

The short version: Determine which stories a diet is using and then do the tough work to figure out a healthy approach to eating you can follow over the long haul.

The details: If a diet appeals to you, ask yourself why. What underlying narratives is the diet pulling from that attract you?

  • Perhaps you think technology is polluting us and that clean eating is the way to purity?
  • Or maybe you believe technology and data is our savior and that, for example, wearing a continuous glucose monitor to fine-tune your food decisions in real-time is critical?
  • Or do you feel like a carnivore diet will allow you to manifest an ancient idea about the role of men in society?

Then forget the story for a moment. See the diet only as a list of foods and behaviors. Consider if you can follow the diet’s food and behavioral rules for the rest of your life.

If the answer is no, it may still be worth trying the diet to learn a few valuable takeaways. For example, testing an elimination diet could reveal foods you’re allergic to.

But the key is to then take the parts of the diet you think you can follow forever and ditch those you can’t.

That harder work will let you find your own approach that changes you.

Thanks for reading. Have fun, don’t die.


P.S. If you want to go deeper on this subject, Bitar’s book is a fascinating read.

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