By Tim Radford

An international panel of health scientists and climate researchers has prescribed a new diet for the planet: more vegetables, less meat, fresh fruit, whole grains and pulses, give up sugar, waste less and keep counting the calories.

And if 200 nations accept the diagnosis and follow doctor's orders, tomorrow's farmers may be able to feed 10 billion people comfortably by 2050, help contain climate change, and prevent 11 million premature deaths per year.