Weight Loss/Maintenance

A pedometer company add campaign in 1965.... I love marketing...

To find out, we must look to Japan. In 1965, Dr Yoshiro Hatano who worked for a pedometer company. He named his new device 'Manpo-kei', which literally translates as,
"10,000-step meter".
Where did this figure come from? Years of scientific research, you'd imagine.
It was an arbitrary number, deemed merely reflective of what constitutes an active lifestyle. On that, an ad campaign was designed. And well, the rest, as they say, is history.

https://www.standard.co.uk/futurelondon/health/fitness-trackers-what-is-the-origin-of-10-000-steps-aday-and-what-are-wearables-a4173306.html