Decreased Physical Activity in the Workplace has Led to Weight Gain

You’ve heard it before, but new research reinforces the idea that sedentary desk jobs could be the primary cause of weight gain over the past five decades. In the early 1960's, almost half the jobs in private industry in the U.S. required at least moderate intensity physical activity. Now less than 20 percent of occupations require this level of activity, leading Americans’ level of daily energy expenditure to drop significantly. Researchers from the Pennington Biomedical Research Center at the University of Louisiana conducted an analysis of occupational energy expenditure in the U.S. beginning in the year 1960 until the present, using data from the U.S. Bureau of Labor Statistics. They also gathered body weight data from different U.S. National Health and Nutrition Examination Surveys (NHANES).

Researchers used an energy balance model to predict people’s weights based on the average change in their occupation-related daily energy expenditure since 1960. For instance, from 1960 to 2006, the NHANES survey data and energy balance model led researchers to estimate that the occupation-related daily energy expenditure decreased by 142 calories in men aged 50 - 60 years. Given a baseline weight of 76.9 kg in 1960, they calculated that the decreased activity would result in an increase in mean weight to 89.7 kilograms, which was close to the actual mean weight (as measured by the NHANES) of 91.8 kilograms in 2006. The same pattern was true in men of different ages as well as in women.

The only way to counteract the increasingly sedentary nature of the American workforce is to increase energy expenditure. For most people, this means hitting the gym after work!

Church, et al. (2011). Trends over 5 decades in U.S. occupation-related physical activity and their Associations with obesity. PLoS ONE 6(5).