The optimal human fasting regimen (e.g., FMD frequency, duration, water-only fasts, weekly fasts) is currently unknown due to the impossibility of studying it with necessary metrics and technology.

“I'm not even suggesting that I have a clue what the optimal fasting regimen is whether you should be doing a five-day FMD quarterly whether you should be doing a seven-day fast quarterly whether you should be doing a five-day fast water-only quarterly whether you should be doing a day a week you know with nothing in it I mean that's the whole point here nobody knows the answer to this question because it would be impossible to study this in humans using the metrics that are necessary to actually extrapolate to the things that matter most with the technology we have they which don't have the tools developed to do this”