Should the world go on a diet in 2014?
There has been a dramatic increase in the numbers of overweight or obese people in the past 30 years. Previously considered a problem in richer countries, the biggest rises are in middle income countries and the developing world.
'Future Diets' traces how the changes in diet - more fat, more meat, more sugar and bigger portions - have led to a looming health crisis. It also looks at how policy-makers have tried to curb our eating excesses - with mixed results.