Check out this docuseries on Netflix called "(Un)Well", which investigates the wellness industry. There are six in the series, one of which is about fasting! I've watched it and it was pretty good - the episode presented various opinions and information about the topic so I found it pretty balanced in presentation. Not surprisingly, Dr. Valto Longo is interviewed in the episode!
Here's the trailer for the series:
Here's an article about the series:
https://www.theguardian.com/tv-and-radi ... s-industry