@stolpioni I would suggest that you do not fast this long on water alone.
1) in the book by mark donohoe
https://static1.squarespace.com/sta...de025/1410769410474/Killing+Us+Softly+1.3.pdf that
@btdt recently brought to everyone's attention Mark mentions that one factor found common in all of the ME/CFS and Multiple Chemical Sensitivities patients he was treating in a hospital ward was that they got liver damage when fasting if they did not have have additional amino acids.
These people quickly showed biochemical evidence of liver damage after only a few days fasting, something which should have taken nearly two weeks. Once the nutritional supply of sulphur containing amino acids (methionine and cysteine) was ceased, the stage II elimination was reduced to pathological levels. The liver cells were damaged simply by their processing of the toxins stored in the body fat, which was mobilised in response to the food reduction. This problem was reversed by simple amino acid supplementation during the fast.
2) Jason Fung
https://intensivedietarymanagement.com/ who recommends fasting for type two diabetics and has a lot of experience with 30 day fasts only does these long fasts with patients under medical supervision and they are not strict water fasts, but contain supplements and, if I remember correctly, broth.
3) I understand from podcasts I have listened to that ketosis massively increases peoples needs for salt and magnesium. I cannot remember which D'Agostino podcast it was but this would be a good place to look for good information for normal people in ketosis
https://ketonutrition.org/resources.
I would also take whichever form of carnitine works best for you to aid fat metabolism as this would seem likely to help.
4) I think it is important to remember that people with ME/CFS are not well people. research done on normal people may not translate to pwme/cfs. Mark Donohoe's experience is the only one I am aware of with lots of people with ME/CFS and that was only 3-4 days.
5) you might want to ask what effect you are seeking.
I have done a lot of intermittent fasting, and a handful of slightly longer 40 odd hour fasts I think the longest was something like 46hrs. Judged from say a religious observance point of view these longer fasts would not have been considered true fasts as I still took all my supplements.
But my doctor and I misinterpreted my 2hr glucose tolerance/insulin test and thought I was prediabetic. Turns out my unusual for normal people pattern was just the normal ME/CFS pattern (strong insulin response but flat glucose response - which should be seen as obviously not insulin resistant but I excuse myself on the grounds of brainfog and desperation).
Anyway as my aim at the time was to deal with insulin resistance so I made sure that I took no significant carbohydrates and proteins when fasting, but did not worry about the trivial amounts contained in the .5 tsp of turmeric I took each morning and afternoon for example.