Human beings did not evolve on three square meals a day. As hunter-gatherers we ate what we could find when we could find it. We used considerable energy to obtain food and as it wasn’t always accessible, we developed a dynamic metabolism that enables us to survive extended periods without eating. However, in today’s developed world with food never far from reach, we don’t often put our ancient metabolism to the test and we treat momentary hunger as something to be crushed, urgently.