I didn’t have luck with water only fasting since I developed awful sciatica-like pain on day 2 each time I tried.
I considered buying the Prolon FMD products but the price & carbs were too high and I didn’t like the foods. By looking at the patent for the FMD, one can apply the percentages of the macros and calories, make a minor adjustment and make a personalized keto version: keep the protein levels the same, move the excess carbs into fats and find foods you like that conform to those parameters.
Having done so, I am completing my 5th FMD following the keto-adjusted protocol. For 5 consecutive months I’ve done 5 day FMDs followed by 25 days of “refeeding”. I test ketones and glucose before my evening “meal” during the 5 days and have gotten Glucose Ketone Index values of below 1.0 during each 5 day fast. The GKI values have ranged from .53 to 3.8 . Usually the highest values are Day 1 to Day 2, then it drops to 2 or below.
Wish I could report some kind of amazing results other than the GKI. I just hope it’s doing me some good and trust the body to know what to do. I’m going to keep up the 5 day FMD, 25 day refeeding indefinitely. If I observe some results or have some awesome labs to report, I will.
I hope this helps somebody. If you have any insights for me, do share.