If you’ve spent even a little time on social media in recent years, you’ve no doubt come across a swathe of “wellness” content.

From kilometre-long lines of runners strutting the Bondi promenade at 6am, to a surge in sauna and ice bath studios, to bizarre routines such as mouth taping, longevity diets and facial ice rollers – looking well is so hot right now. And being seen to be well has become the social currency of our times.

But perhaps there are also other forces at play here, as wellness culture seems to tap into age-old human preferences for vitality, fertility and social status.

Read more: Why do smart people get hooked on wellness trends? Personality traits may play a role

Humans evolved to notice and prefer visible signs of health. Outward signs of potentially contagious disease tend to evoke disgust reactions in us. This is part of the “behavioural immune system” – a series of preferences we evolved to avoid infection over thousands of generations when contagious diseases were both more common and less well understood than they are today.

But there’s more to it than just avoiding people who might be infectious.

Research suggests we are often drawn to people who have glowing skin, symmetrical faces, healthy body composition, and who

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