LONDONGlobal population growth threatens environmental sustainability, and a new study published in the journal BMC Public Health suggests the global obesity epidemic is a major threat to food security. The findings suggest that the increase in overweight population could have the same effect on world food energy demands by 2050 as an extra 1 billion people.

According to the United Nations, the global population is predicted to grow from 7 billion in 2012 to 8.9 billion by 2050. Now, more than ever, there is increased pressure to find efficient and sustainable ways to feed the global population.

Researchers at the London School of Hygiene & Tropical Medicine said peoples weightnot just population sizeshould be taken into account when planning how to deal with increasing pressure on the planets dwindling resources. Up to half of all food eaten is burned up in physical activity. Increasing mass means higher energy requirements, because it takes more energy to move a heavy body.  Even at rest a bigger body burns more energy.

Using data from the UN and the World Health Organization (WHO), the researchers estimated the adult human population weights 287 million tons15 million of which is due to the overweight and 3.5 million due to obesity. While the average body mass globally was 62kg, North America, which has the highest body mass of any continent, has an average body mass of 80.7kg. North America has only 6% of the worlds population, but 34% of the worlds biomass mass due to obesity. In contrast Asia has 61% of the worlds population but only 13% of the worlds biomass due to obesity. The said if all countries had the same average BMI as the United States, the total human biomass would increase by 58 million tonsthe equivalent of an additional 935 million people of world average body mass.

Everyone accepts that population growth threatens global environmental sustainabilityour study shows that population fatness is also a major threat. Unless we tackle both population and fatness our chances are slim," the researchers concluded.