Exercise

The first episode.



He is starting small, yes.  It was geared to housewives, and the idea of exercise at home was new then.  No use scaring people away.  The more aerobic style, and calling it a "workout" was way in the future.

Jack was the first on TV, but before him was Charles Atlas and before that there was Bernarr McFadden. 

Bernarr was an early advocate of fasting - serious fasting of a week at a time - lifting weights, vegetarianism, and avoiding white bread.  If that sounds like a man who was before his time, he also thought grapes would cure cancer, and never went to see a physician himself.  He died of a urinary tract infection at 87 because he would not seek medical care.  I suppose you could argue either way from that data whether he succeeded or not.