The only thing I've read that doesn't completely fire off my "bullshit warning mode" is something like "fasting can enable stem cells, and have immune system destroy old cells" like explained here: https://www.telegraph.co.uk/science/2016/03/12/fasting-for-t...

Still seems a little too "high level" to actually believe though. In any case, I still do IF by skipping breakfast, mostly because I'm lazy, and after fasting for so many years hunger doesn't really bother me that much.