I agree that we're probably adapted, in our biology, to re-occurring intervals of food scarcity. I would not be surprised at all if it turned out that our bodies actually function better on that sort of regime (eat at will for a while, then forego all caloric intake for a brief period).
I wonder if this was noticed at the dawn of civilization, and then got codified into religion and so on.
Yeah it's interesting how ancient cultures seemed to have (by trial and error I suppose) incorporated specific behaviors into their culture which, in hindsight, solve a particular problem that can be scientifically identified.
An example I love is the Canadian Inuit who traditionally ate no vegetables for 10+ months of the year without developing scurvy. The tradition of eating raw whale blubber and fish (including the broth) preserved the vitamin C and minerals from the mea, while eating cooked meat without broth drastically reduces mineral and vitamin intake.
I wonder if this was noticed at the dawn of civilization, and then got codified into religion and so on.