Food

Don't be mistaken. I am all for a healthy diet – but for a different reason.

The argument is simple: the productivity of an area of land that is needed for your dinner of 12-oz sirloin steak can keep the same you fed for a whole week with rice, vegetables and to-fu. High school ecology teaches us that energy conversion from the sun to grass, and then cow always means more wastage than from sun to rice or potato.

(And when a big country has remarkable economic growth and many of the people become meat-lovers, it inevitably uses more farmable land - despite of its successful policy on birth control.)

Of course it is a real dilemma whether we should try and feed as many people on earth as possible - by eating more vegetables and less meat - or to keep a variety of diet (after all, cookery is an important part of human civilization) and aim to have fewer people.