The study by the US Centres for Disease Control and Prevention warns that the annual death toll from obesity-related conditions is heading towards 500,000. CDC researchers estimate the number of US deaths due to poor diet and lack of exercise jumped by a third between 1990-2000, while smoking-related deaths rose by less than 10 per cent. More than 60 per cent of US adults are overweight or obese, and childhood obesity is skyrocketing. In 2000, an estimated 400,000 deaths – 16.6 per cent of the US’s 2.4 million total – were related to poor diet and exercise habits, according to the CDC analysis published in the Journal of the American Medical Association. Tobacco still held the top spot as the leading preventable cause of death: lung cancer and other tobacco-related diseases accounted for 435,000 deaths or 18.1 per cent of the total in 2000.