A new study suggests that a move to more sedentary jobs may be another big factor behind the U.S. obesity epidemic.
Research published Wednesday in the journal PLoS One reviewed changes in the American labor force since 1960. The study found that jobs requiring some sort of moderate physical activity have dropped from 50 percent of the labor market in 1960 to just 20 percent today.
"If we're going to try to get to the root of what's causing the obesity epidemic, work-related physical activity needs to be in the discussion," lead author Dr. Timothy S. Church, an exercise researcher at the Pennington Biomedical Research Center in Baton Rouge, La., told The New York Times. "There are a lot of people who say it's all about food. But the work environment has changed so much we have to rethink how we're going to attack this problem," he added.
According to the authors, a shift from a job requiring moderate physical activity to one that is wholly sedentary, or requiring only light activity, means a drop in daily energy expenditure of 120 to 140 calories per day.
While a decline in the percentage of Americans involved in farming-related jobs has contributed to the trend, Church said that losses in the manufacturing sector have mattered, too.
"You see the manufacturing jobs plummet and realize that's a lot of physical activity," he told the Times. "It's very obvious that the jobs that required a lot of physical activity have gone away."