Fad diets have long been brushed off as selfish, superficial quests to lose weight.

But if you study the actual content of popular diet books, you will discover that most tell a different story. Many inspire dieters to improve the health of their bodies, society and the planet.

It’s a topic I explore in my research, as well as my 2018 book, “Diet and the Disease of Civilization.” More than than merely guides for getting thin, diet books tell rich stories that urge people to change their lives to save the world.

Grand ambitions

Diets inspire change not because one is more effective than another, but because they tell stories worth believing in.

Peel away the nutrition advice and you’ll find that, while most popular diets ennoble seemingly selfish goals, they also insist that individual health is inextricably linked to the larger environment.

A quick review of diet books reveals their grand aspirations. Think of the Paleo diet. Hundreds of Paleo diets describe peaceful prehistoric communities rich with singing, dancing and storytelling. Today, leaders promise that “eating Paleo can save the world.”

Promoters of detox diets make similar claims. Detoxers believe that environmental pollution and toxins cause stress, obesity and other modern ills.

A detox book from 1984 argued that humans cannot “dissociate our fate from the fate of the earth” and insisted that “what we have learned about freeing our bodies from harmful substances must also apply to cleaning up the world.”

Today’s diets go a step further, intimating that if you’re not “eating clean” you could be eating “dirty” foods full of pesticides, toxins and carcinogens. One diet book explains that clean foods are “not only good for one’s health, but equally important for the environment.” “The Kind Diet,” a popular vegan book written by actor and animal rights activist Alicia Silverstone and Victoria Pearson, is subtitled “A Simple Guide to Feeling Great, Losing Weight and Saving the Planet.”

Diet consequences

Arguably, today’s food world could use some saving.

The health consequences of how Americans eat have long been cataloged. For example, 2 in 3 Americans are overweight or obese, costing the U.S. economy an estimated US$190 billion a year.

But the environmental consequences of these food choices are just as stark. Agriculture is responsible for about one-tenth of greenhouse gas emissions. Farming consumes more than two-thirds of the planet’s fresh water.

And it’s specific dietary choices that are driving these environmental pressures. Animal products, for example, provide just 18 percent of the typical American’s calories yet take up 83 percent of all farmland. Just cutting down on beef would be more effective at reducing your carbon footprint than giving up your car.

The government’s role

This is where the government could learn from popular diet plans and promote sustainable diets for public health and the environment.

In its dietary guidelines, the U.S. Department of Agriculture encourages Americans consume a healthy diet that focuses on foods high in nutrients and low in sugars and saturated fats. But despite the recommendation of an advisory committee, it does not include language about food system sustainability or how such diets have a well-established link to human health.

The government is also discouraging other steps toward an environmentally friendly diet. Consider the new technologies of culturing meat from living animal cells – a technology that could cut out 14.5 percent of Americans’ anthropogenic greenhouse gas emissions. At the same time, the government is bending to industry concerns and enforcing needlessly strict definitions of meat, preventing soy- and lab-based products using the label.

History shows that today’s Department of Agriculture is missing a valuable opportunity. During World War I, the American government used diets to do more than improve individuals’ health. As the head of the Food Administration, Herbert Hoover urged Americans to stop wasting food so the U.S. could use it to prevent starvation in Europe. His efforts are now credited with saving the lives of about 7 million Belgians and 2 million French people.

Popular diets also picked up the humanitarian cause. One 1918 diet included a program dubbed “Watch Your Weight Anti-Kaiser.”

Today’s food authorities could do the same: urge Americans to eat better because the food system is actually a web. Our food choices have a profound impact on our health and the planet.

Adrienne Rose Bitar does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.