I Inadvertently started intermittent fasting when I started my 2006 Appalachian Trail (AT) thru-hike. I felt like crap in the beginning, because I was taking in far fewer calories than I was burning throughout the day of hiking up and down the Appalachian mountains. I usually hit a town anywhere between 1 & 2 weeks, so I had to carefully ration my meals, since you can carry only so much food.
After a few weeks I was feeling better and better, i.e. stronger and stronger, but my basic diet never changed. This impressed me so much I looked into it after the hike and that's when I learned about intermittent fasting. That's basically what one is forced to do when hiking day-after-day in the mountains, while rationing food.
I now to this purposefully. It's very common for me start on a 40+ mile ride in the morning without eating any food and I don't eat any thing during my rides, including gels and sports drinks -- only water. That would have been unthinkable before and I probably would have hit the wall, because my body was never trained to do that.
I do believe intermittent fasting and eating very healthy home-grown foods are so important to our health, more than most people know.
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