Cavemen were not health planning wonks. And when it comes to foresight about our own wellbeing, today's humans are still pretty blind. Our brains were made to think "now", not two years from now, which is why the idea of chocolate fudge today is so much more forceful than the image of a weigh scale reading a year from now. So when we humans come up with an idea about health that is future-oriented - living longer, for instance - and we actually motivate a town to think ahead and set itself in motion to get its citizens an extra …