If you haven't come across it, the Radio 4 series The New Gurus is excellent.
Writer Helen Lewis explores the background to the current boom in online gurus, and locates it all in a bigger history of faiths and -isms.
Each 30-min episode explores a particular area, such as Wellness/Diet, Productivity or Bitcoin. Stimulating and sobering listening.
Link to the whole series on BBC Sounds here:
www.bbc.co.uk/sounds/brand/m001g9sq