The weight of the world

Being overweight and obese is often portrayed as a big problem for individual health. There is no doubt that this is true as being overweight significantly increases your chances of developing diseases including diabetes, cancer, and heart disease. Now a new study has shown that being overweight is not only bad news for the individual, it is also a big problem for the planet.

Using data from the World Health Organisation and the United Nations researchers have estimated that the human population currently weighs in at 287 million tonnes. That collective figure is known as the “biomass” of humanity. It is important because biomass dictates a lot of the impact that a species has on the environment.

Around half of the food that a human being eats is burned up in physical activity but the more mass a person has, the greater the amount of food that they need to generate the same amount of activity. This is because it takes more energy to move a heavier body around. Then again, even when not moving, a heavier body will burn more energy. So a greater overall human biomass due to obesity and overweight will mean greater energy consumption and greater demand on the planet’s resources.

Digging into the data some scary statistics emerge. While North America only has six per cent of the world’s population it has 34 per cent of the world’s biomass due to obesity. By contrast Asia comprises 61 per cent of the world’s population but only has thirteen per cent of the world’s biomass due to obesity. If all countries had the same Body Mass Index as the USA then the global biomass would increase by 58 million tonnes which is equivalent to an additional 935 million people of average body mass.

Overall, of the 287 million tonnes of human biomass around 15 million tonnes is estimated to come from overweight and 3.5 million tonnes from obesity. That means that the effect of people being overweight or obese is like adding another half a billion normal weight people to the seven billion humans on the planet. In turn that means greater demands on resources and in a future where food is predicted to be scarce anyway and with the population predicted to hit 8.9 billion by the year 2050, the obesity epidemic might be unsustainable for both individuals and the planet.