The study shows today's workers burn an average of 120 to 140 fewer calories a day at their jobs than those in the 1960s.
Researchers said the lower activity level is due to an increase in office jobs that are mostly sedentary, and a dramatic drop in the number of active jobs in manufacturing and farming.
The study also emphasizes that a significant portion of the increase in obesity could be accounted for by the decrease in physical activity at work.
