Hi Ketolife. I have been low carb for about a year and I had no disturbing headaches/tiredness etc (the 'keto flu') because of that. The Nobel Prize for medicine was awarded to Yoshinori Ohsumi in 2016 for his work on autophagy which is one of the benefits of the water fast. That's when damaged and less helpful proteins and other cellular debris gets 'eaten' up by the body and used for energy. It seems that twice or three times a year would be very beneficial for everyone. Good luck again. ps I was in therapeutic ketosis for about 4 days last fast. I felt great. PJ