Global weight gain is turning into a bigger threat to mankind than population growth. According to researchers, the adult human population has a combined weight of 316.4 million tons. Increasing obesity will soon have the same impact on resources as an extra billion people on the planet, researchers believe. The BBC has put together a calculator that will compare your body mass index (BMI)—a measure doctors use to gauge obesity—to others from your country and rank it against people from other nations. The BBC calculator uses age, sex, nationality, height and weight to come up with its BMI calculation.