A report published on BioMed Central calculated the total human biomass of the planet’s adult population at 287 billion kilograms. Measures included population size; a person’s fat content, also known as body mass index (BMI); and height.  About 15 billion kg of this total human biomass was due to overweight people. The report states: ‘Although the concept of biomass is rarely applied to the human species, the ecological implications of increasing body mass are significant and ought to be taken into account when evaluating future trends and planning for future resource challenges. 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. Tackling population fatness may be critical to world food security and ecological sustainability.’