It really seems so. I'm not happy to say this phrase but - 'do some research'. The only reason I'm saying it is because I know you have an evidence-based attitude.
As for Fung, he's a good opening step, but I'd take some of what he says with a grain of salt, the same as anyone else who has a financial interest in things they're punting.
@Sinbad, start with autophagy - and the work of Yoshinori Ohsumi - and work from there. The problem with relying only on science here is the reason why you can't really rely on a lot of research when it comes to these things - abscence of meaningful data (no large group of people have been tracked 100% on a long enough basis), and everyone's physiology is different.
I can also advise delving into reddit.com/r/fasting
A lot of people here I know started off very sceptical of keto, and it made sense to be sceptical since it goes against most of what we've been taught. We've since learned better.
Fasting is no different in that regard.