Fasting, in particular prolonged fasting (up to 40 days of water fasting or 8 days of dry fasting) is the best gift you can give to your body.
https://www.ncbi.nlm.nih.gov/pubmed/28202779
Also, it seems to regenerate β cells for Type 1 diabetes humans, although I would imagine the "regular" fasting would do that, too since it's a more extreme version of the FMD:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5357144/
Some interviews with him on it (there are more on youtube):
https://www.youtube.com/watch?v=d6PyyatqJSE