For example, North America has 6 percent of the world population but 34 percent of biomass due to obesity. Meanwhile, Asia has 61 percent of the world population but just 13 percent of biomass due to obesity.

Using data from around the world for 2005, researchers used body mass indexes (BMI, or a measure of body fatness) and height distributions to estimate average adult body mass. They then multiplied these results by population size to get a total mass, referred to as biomass. They evaluated body mass using BMI thresholds of greater than 25 for overweight and greater than 30 for obese. The collective mass of the adult population in 2005 due to obesity was 3.9 million tons (3.5 million metric tons), they calculated…

“Our scenarios suggest that global trends of increasing body mass will have important resource implications and that unchecked, increasing BMI could have the same implications for world energy requirements as an extra 473 million people,” they write. “Tackling population fatness may be critical to world food security and ecological sustainability.”