I did intermittent fasting 2 days a week for 2 years (2013-2015). Initially I lost weight, which was good. Energy levels were elevated, minor health problems seemed to have gone away or lessened. Towards the end, I think I was being rather too "soft" on myself, so wasn't really reaping the benefits, and it got to be a grind. I then had some rather unpleasant emotional issues to deal with, and found I didn't have the emotional energy to continue: I have pretty decent willpower, but when I'm badly emotionally stressed, it crumbles. I've been intending to get back into I/F ever since, and though I'm emotionally in a far better place, I haven't managed to muster the emotional energy for it yet.