Obesity is an unintended but unavoidable consequence of economic progress. Obesity is not a disease but a signal. It should alert us to bigger structural problems in society. On the one hand, economic growth has over centuries led to a steadily improving standard of living, better levels of health and ever-increasing life spans. On the other hand, this very affluence is the reason that both our bodies and the planet have gone into a downward spiral, manifested by an ever growing epidemic of obesity in humans, and in a world clogged by greenhouse gasses and waste. Our bodies can no longer cope with the excess of over-consumption to which we are encouraged at every turn, and the planet is labouring under the effect of industrialisation and greenhouse gas emissions. A fundamental change in thinking is needed both for how we treat our bodies and for our approach to the planet. Each is the only one we have.