Facts that should change the world

Out of the 300 million people in the world who suffer from obesity, one in three lives in a developi

For the first time, the number of overweight people on the planet is starting to rival the number of underweight people. The World Health Organisation says obesity rates have risen threefold in the past 20 years, largely as a result of urbanisation. Rather than eat fresh fruit and vegetables, people opt for highly processed, energy-dense foods, heavy in fat, sugar and salt. They also lead increasingly sedentary lifestyles. Obesity-related conditions cost the US some $118bn in the 1990s - more than double what was attributable to smoking. Now, most such chronic disease occurs in the developing world, where health systems already struggle.

In China, 20 per cent of the population in the cities is classified as obese. Obesity among Thai children aged between five and 12 rose from 12 per cent to 15-16 per cent in two years. In Mexico, where in some remote villages it is easier to buy a bag of crisps than a banana, 64 per cent of the women are overweight.

In the Pacific islands, cheap imported foodstuffs have brought obesity, once possible only for the very rich, within most people's range: it is now 77 per cent in Nauru. High-fat meats once used in the west as pet food or fertiliser - turkey tails from the US, lamb and mutton flaps from Australia and New Zealand - are sold as delicacies and locally caught fish is between 15 and 50 per cent more expensive. The export of such meats has been described as "dietary genocide". But when Fiji tried to ban them, New Zealand threatened to lodge a complaint with the World Trade Organisation.

Adapted from Fifty Facts That Should Change the World by Jessica Williams, just published by Icon Books (£9.99)