Obesity Seen as Environmental Problem
For years, scientists have tracked the number of people on earth, creating health initiatives and food-need forecasts based on population growth projections. But body mass, which directly determines a person's energy and food requirements, rarely gets the spotlight.
To fill this gap, a team of London-based researchers drew on 2005 body mass data from the United Nations and the World Health Organization. Its results, published in BioMed Central's open access journal BMC Public Health, estimate the total adult human population weighs 287 million tons, of which 15 million tons are due to overweight and 3.5 million tons due to obesity.
The data also reveal striking differences among regions of the world. North America weighs in with just six percent of the Earth's population but 34 percent of its human biomass due to obesity. In contrast, Asia, with more than half the world's population, has less than 13 percent of its obesity-related biomass.
More importantly, individual body mass levels are rising around the world. The study's authors say that if all other nations had the same average body mass as the U.S., the world's total human biomass would increase by 58 million tons. That would be like adding nearly a billion world-average-weight people to the planet. The researchers say this would have dire consequences for the world's ability to feed itself.
“Unless we tackle both population and fatness,” says study collaborator Ian Roberts, “our chances are slim.”