I've been reading Antifragile by Nassim Nicholas Taleb. He's a former trader, lately academic, who studies risk and such. The theory of this book is that biology and human social systems (government, economics, infrastructure design) can be classified according to how they react to external variances. A fragile system breaks on modest variances in environment, a robust system holds the same, but certain systems actually grow stronger when subject to external pressures (to a point). He calls such systems antifragile, and then proceeds to describe how they work and can be implemented for a stronger society. Think of how the body becomes stronger when exercised, but weakens when not subject to environmental stressors such as the need to run or to lift things.
He includes a critique of modern medical theory and encouragement for periodic fasting, Vulcanbill's point. More specifically, he advocates that humans didn't evolve with three squares a day and a complete blend of nutrients at every meal. His point is that periodic fasting, and eating foods seasonally or having meatless days, encourages our bodies to better absorb and hold onto nutrients.