The first study to calculate the impact on the environment of growing waistlines has estimated that the adult human population weighs in at 287million tons, 15million of which is due to the overweight and 3.5million due to obesity.
Researchers from the London School of Hygiene & Tropical Medicine found most of the extra weight was concentrated in the richest part of the world, with the US heaviest and Britain coming in at 18th, despite its small population.
The study said that over–consumption was not only shortening people's lives but also driving climate change and the destruction of the environment. The study will be presented at the United Nations' Rio+20 conference.
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The research, published in the journal BMC Public Health, drew up a league table of the nations that have the biggest share of obesity.
The American adult population is the heaviest. While the average body mass globally was 136lb 10oz (62kg), in the US it was 177lb 14oz (80.7kg). Despite having only 5 per cent of the world's population, the US accounts for almost a third of the weight because of obesity. In contrast Asia has 61 per cent of the population but only 13 per cent of the excess weight.
The British adult population is 30lb 7oz (13.8kg) fatter than the rest of the world, with an average adult body mass of 167lb 2oz (75.8kg)
Prof Ian Roberts, who led the research, said “fatness” was as much a threat to the environment as over population; it increases energy consumption, meaning heavier countries use more resources, driving deforestation and the release of greenhouse gases.
Prof Roberts pointed out that people did not necessarily eat more than 50 years ago, but moved less because of the use of machines. “We do not move our bodies so much, but we are biologically programmed to eat,” he said.
“The difficult thing is the whole world is getting fatter. It's not about obesity it's about fatness. If every country becomes as ft of the US then in mass terms it's like having an extra billion people in the earth or feeding another half a billion.
“Your body is a vehicle designed for your personal transportation and is fuelled by food. So if you have a big body you consume more food than a small body.”
He recommended the world go on a diet, calling for health programmes and more efficient energy and food production, and added: “Everyone accepts that population growth threatens global environmental sustainability – our study shows that population fatness is also a major threat.
“Unless we tackle both population and fatness our chances are slim.”
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