Washington: The global obesity epidemic today may be linked to sedentary jobs, as they hardly involve any physical effort, says a study.
Only one-fifth of private jobs in the US today and other countries require much less physical activity than half a century ago.
Automated systems and computerisation have turned physically demanding jobs into desk-bound ones, according to researchers from Louisiana State University, in the US, reports the journal Public Library of Science ONE.
John S. McIlhenny, who led the study, said: "We estimate that daily occupation-related energy expenditure has decreased by more than 100 calories per day, and this reduction accounts for a significant portion of the increase in mean US body weights for women and men."
McIlhenny and team gathered data from National Health and Nutrition Examination Surveys, as well as the Bureau of Labour Statistics, according to a Louisiana statement.
A total of 100 calories may not be a big thing, but if piled on for 180 working days, would add up to a staggering 18,000 extra calories or two kg of fat.
Study authors also attribute obesity epidemic to lack of physical activity. Fifty years ago more people commuted by bus or train and got off and walked to their workplaces.