An obese young woman pushes a pram along the road





















 More than half of people in Europe are overweight, while in North America it is almost three-quarters

Scientists are warning that if obesity continues to grow the world's population is in danger of running out of food.

The problem could have the same implications for world food energy demands as an extra one billion people, researchers claim after examining the average weight of adults across the globe.
The authors of the study - scientists from the London School of Hygiene and Tropical Medicine - said that the energy requirement of humans depends not only on numbers but average mass.

Unless we tackle both population and fatness, our chances are slim.
Professor Ian Roberts, report author 
And tackling population weight is crucial for food security and ecological sustainability, they suggest.
"Everyone accepts that population growth threatens global environmental sustainability - our study shows that population fatness is also a major threat," said Professor Ian Roberts, who led the research at LSHTM.
"Unless we tackle both population and fatness, our chances are slim."
The world's adult population weighs 287 million tonnes, 15 million of which is due to being overweight and 3.5 million is due to obesity, according to the study being published in BMC Public Health.
The data, collected from the United Nations and the World Health Organisation, shows that while the average global weight per person was 62kg in 2005, Britons weighed 75kg and the average adult in the US weighed in at 81kg.
Across Europe, the average weight was 70.8kg, compared with 57.7kg in Asia.
More than half of people living in Europe are overweight compared with only 24.2% of Asian people. Almost three-quarters of people living in North America were overweight.
The United Nations predicts that by 2050 there could be a further 2.3 billion people on the planet and that the ecological implications of the rising population numbers will be exacerbated by increases in average body mass, researchers said.
They forecast that if all people had the same average body mass index as Americans, the total human biomass would increase by 58 million tonnes.