I have done a 23 day water fast and a 29 day water fast. Im an iron worker with a physical job and I put in lots of overtime. After the 4th day of fasting, its smooth sailing. Energy and mental clarity happens when you switch over into ketosis. Fasting is one of the best things I have ever discovered. I feel and sleep sooooo much better when Im not packing around extra weight (plus all the bennies that come with a long fast) Now I just do a 5 day every month (during one work week) Sometimes I skip a month. The only downside I noticed when fasting is getting lightheaded for a few secs if I stand up too fast.
I love eating keto but since the woman is always getting ahold of free sources of food and is always bring boxes of it home ..... its hard to eat that way. We have a very large supply of food that has to be rotated and used.