“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........

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