fasting honest to god is not that hard, and it doesnt negatively impact your life  If anything, I feel that an occasional fast offers some significant benefits. In particular,  I like knowing how food impacts my mind and body. Doing it casually every now and then informs choices later down the road when it's a more pressing issue. In particular when you're dealing with limited resources or space.  For example, there's no "oh crap gonna starve!" moments if you want to extend a hike a little longer than planned. As you say, it's a natural way of life. Our hunter gatherer ancestors didn't always have the luxury of readily available food. Part of that lifestyle is needing to actively search for food when resources are slim to totally absent. If they had to sit down to three solid meals a day in order to fuel the search for more food than our species would have gone extinct pretty quickly.  My only caveat is that I suspect people need to be in reasonably good health to get through longer fasts without much negative impact on overall performance. Ironically, that implies fat people would be the least able to get through a fast while still keeping up some reasonable level of activity.