Well, I kind of stumbled into this, I was traveling for work, feeling horrible, eating carbs. I was listening to Tim ferris, Podcast in IF, fasting, and brain enhancement http://tim.blog/2017/05/04/smart-drugs-fasting-and-fat-loss/
while working out at gym. I stumbled on 2 keto dudes and binge listened for days.
I decided it was easy to fast while traveling for work cause I keep busy and save money. 5 days in head home and feel better though not perfect. I'm home for 3 days and back on road for 4th so stayed on. I read dr fongs book and this forum and podcasts, for support. The salt fix was the perfect episode as I've been taking a lot of salt I bought and reading the book.
I figured I would do 2 weeks I think it was recommended as therapeutic, but now I am on day 17 and going strong.
After 2 weeks I felt amazing I think it was the carbs and I workout Every day, that helps. Now I am good for as long as I want to. I did need to cook food for family and taste things, but I found a way to spit it out without issue it gross factor, funny thing is after tasting things, they taste completely different it is so weird. After the first couple tastes I gave up and had my daughter be the taster.
The first two weeks was tough and slept a lot, drank a lot of water / supplements and was lethargic, but after 2 weeks I had boundless energy and found I could control everything I had a tendency to just do, watching TV or playing games.
I travel to a place I used to live and day before I fasted I saw my doctor / friend, to make sure it was OK. He said I'm in "good health" and if I feel bad in any way to stop, also he said let friends and family know so if I have issues they know. The big one was he said drink water and salt was good too, if hunger it pains persist then reconsider, it always helped so I'm going strong.
17 days and counting. BTW I am/was about 38% body fat so I've got plenty of fat to spare, if I had less I might reconsider going so long.
Sorry for such a long post but it might add some context.