I don't think I could make the 72 hours nor do I think that length of time is absolutely needed...if I remember correctly the cellular benefits would begin around 24 hours in and for SURE by 36-48 they'd begin to max out...but that is purely speculation I don't have lab results or studies to back up that belief.
I love intermittent fasting...somewhat eat what I want most days a week when I train and do a ~20 hour fast 2 days a week. Keeps me pretty lean and the fasted days oddly I have MORE mental clarity and feel fine... week 1-2 sucked but once you get used to it and learn to stay BUSY it's easy. Body weight stayed about the same but got leaner and strength went UP. On the fed days you consume maintenance to slightly over maint calories and get MORE carbs than what you would on a carb cycle style diet...
I've tried 3-4 days fasted and lost a bunch of weight...didn't want to take it further than 9-10% bodyfat so swapped back to the 5 fed days and 2 fasted to maintain and so far so good.
On the subject of immunity....EVERYONE around me got the flu (and 2 even got pneumonia)...even with my up early to train and working several things now long hours...I think I sneezed once. lol Didn't get sick at all. Study of ONE I know but...the body really was "designed" and intended to fast for periods of time.
I love intermittent fasting...somewhat eat what I want most days a week when I train and do a ~20 hour fast 2 days a week. Keeps me pretty lean and the fasted days oddly I have MORE mental clarity and feel fine... week 1-2 sucked but once you get used to it and learn to stay BUSY it's easy. Body weight stayed about the same but got leaner and strength went UP. On the fed days you consume maintenance to slightly over maint calories and get MORE carbs than what you would on a carb cycle style diet...
I've tried 3-4 days fasted and lost a bunch of weight...didn't want to take it further than 9-10% bodyfat so swapped back to the 5 fed days and 2 fasted to maintain and so far so good.
On the subject of immunity....EVERYONE around me got the flu (and 2 even got pneumonia)...even with my up early to train and working several things now long hours...I think I sneezed once. lol Didn't get sick at all. Study of ONE I know but...the body really was "designed" and intended to fast for periods of time.