“Wellness” is a word influencers use as a hashtag on videos of them pouring collagen into smoothies and as the theme of a celebrity chef’s new cookbook. It’s even an obsession of the US health secretary. But what does it mean to be well? That’s the question we answer this week on Explain It to Me, Vox’s call-in podcast that answers the questions that matter to you most. While the multibillion-dollar industry feels new, it’s been over a century in the making. Jonathan Stea, a clinical psychologist and author of Mind the Science: Saving Your Mental Health From the Wellness Industry, says that a lot of wellness trends fill in gaps in health care. That cold plunge or super food may be harmless, but often the science behind the trends can be iffy. “The problem is that one of the ways in which wellness promoters market their materials is by promoting quote-unquote ‘science’ or ‘research’ to support their claims,” he says. “When you do a deeper dive into that research, what people will often find is that you can find a study to promote or to support any kind of treatment or claim.”How did the wellness trend even begin in the first place? And how should we be thinking about our health overall? Below is an excerpt of our conversation with Stea, edited for length and clarity. You can listen to the full episode on Apple Podcasts, Spotify, or wherever you get podcasts. If you’d like to submit a question, send an email to askvox@vox.com or call 1-800-618-8545. Where did wellness originate?We can trace the modern wellness industry back to about the late 19th century. That’s when two prominent figures really played a role in shaping the modern wellness industry we see today. One of those players was a guy named John Harvey Kellogg. And what he and his brother Will Keith did is, they built something called the Battle Creek Sanitarium, which was a really huge famous medical center. It was a spa, it was a grand hotel, and it attracted a lot of wealthy, highly influential people. And what John ended up doing in that center was promoting a lot of his ideas about health and about how to treat diseases. They tended to really blend a lot of what he called Biologic Living, which is really just a kind of virtuous way of approaching our health and kind of blending that with some religious Christian beliefs. When I hear the name Kellogg, I admit that I think of my breakfast cereal. Was John Kellogg a scientist or an inventor of some kind? Kind of, yes. So his brother Will Keith actually started the cereal company. John was a physician, and he was a bestselling author. He had a magazine; he did lectures. His magazine was followed by millions of people. So was he the inventor of wellness as we know it today? Not quite. When he was promoting his ideas, it was before the term wellness as we use it today was formed. He was promoting a precursor to wellness called Biologic Living, which essentially promoted the idea that all diseases in all health conditions can be treated with basically a trifecta recipe of good sleep, good exercise, and eating a specific diet: vegetables and fruits, etc. Exercise, diet, sleep, eating fruits and veggies — that feels like something I hear from my doctor. Totally. That’s a part of evidence-based care, and that’s really foundational to what we do in the hospital. The problem is that what we see even in the modern wellness industry is when people sell these things as a cure-all, as a panacea for all health conditions. John had a lot of ideas that [suggested] if we weren’t following a trifecta recipe of sleep, eating well, and exercise, and we were doing other things like drinking alcohol or eating meat or sugar, or even if people were overweight — he considered that to be non-virtuous, and essentially really bad behaviors. And he would view it in a very punitive way. Even masturbation was considered self-abuse by John Kellogg, and he thought that it would lead to things like mental illness and cancer and moral destitution. He would advocate treating people who would masturbate — in boys, he would recommend circumcision or bandaging their hands together, and in girls, he would recommend [applying] pure carbolic acid to the clitoris. And even its removal. Was John Kellogg the only person like this of his time, or was this more widespread? It was more widespread, and I would say that he was one of the most prominent ones. There was another huge player that played a role in the birth of the modern wellness industry: He was a guy named Bernarr MacFadden, who some consider the 20th century’s first celebrity health influencer. This guy was equally eccentric to John. Macfadden would strut around New York barefoot so that his soles could absorb the earth’s energy, and he would sleep on the floor so that his energy would align with the earth’s natural magnetic rhythm. And he was very hostile to vaccines. So you’re telling me that an anti-vaxx wellness influencer is not a new phenomenon. Very old, over a century old. Similar to Kellogg, you know, Macfadden would also sell this idea of health as a moral virtue, where it’s all about virtuous eating. It’s all about virtuous exercise. And the problem with these ideas is that health is not a moral virtue. What these ideas do is they promote an idea about health that ignores the science. And then they downplay the role of other important things that we know play a role in health, like genetics, social factors, and just plain old bad luck. It’s very interesting that all of this happened in the 19th century. I think of that as a time with a lot of advancements in science and in health. Totally. Around the same time that these wellness ideas were percolating, there was also something called the Flexner Report of 1910, and that really ushered in the dawn of modern medicine. What that report did was it essentially wanted medicine and medical schools to get their act together and make them much more scientific. It would encourage schools to either get rid of alternative medicine from their curriculum or just shut these schools down altogether. At the same time, [the report] really disadvantaged folks who were economically underprivileged. And what that did is it opened [a space] for alternative medicine or wellness to step in and to take on the role of listening, humanizing, and comfort. What about the term wellness specifically, though? When did that officially become a thing? Some consider the father of the modern wellness industry to be Halbert Dunn. He was a biostatistician, and he first used the term wellness as we use it today, publishing an article in the Canadian Journal of Public Health in 1959. What Dunn did is he distinguished good health, which he defined as freedom from illness, from what he dubbed high-level wellness, which is a kind of optimal functioning in one’s environment. And I think his definition was quite thoughtful, but it really didn’t stick. The problem is that from there, the term wellness quickly took on a life of its own. And nowadays, in many parts of North America, wellness is everywhere and anywhere, and the definition has really ballooned to include anything and everything. If we ask one wellness guru to define wellness, we’ll hear a different answer from another one.