A shift in the past 50 years from a manufacturing toward a service driven economy, accounts for a significant portion of the increase in the average weight of U.S. men and women, new research suggests.
Figuring out why Americans’ girth size has mushroomed has focused on two areas: calories in and calories out. Given that leisure-time physical activity has remained relatively constant over the past three decades, it’s logical to conclude that an increase in daily caloric intake has largely contributed to the current obesity epidemic.
While this assumption seems logical into doesn’t take into consideration the energy we exert at work. A small change in these numbers would have a greater impact on caloric expenditure because we spend far more hours working than in engaging in any leisure-time activity.
By using data from the U.S. Bureau of Labor Statistics, researchers found compelling trends in the work environment.
In the 1960s, almost half of U.S. jobs required a moderate level of physical activity. Roll forward to 2008 and the opposite is true. Roughly 70 percent of jobs are in the service industry and these occupations require just light physical activity or largely sedentary in nature (professional services, health/education, leisure/hospitality). In 2008, just 20% of jobs required moderate physical activity compared with 48% in 1960.
Combining labor data with national health surveys, researchers were able to quantify this difference in calories used based on occupations. They estimated that from 1960 to 2008 there was a drop in work related calorie consumption of 140 calories for men and 124 calories for women. These numbers don’t sound like much but the calorie surplus adds up over time.
Using a model, researchers were able to predict the average weight increase of 40-50 year olds during this 50 year period. What they found is that the predicted weight gain closely matched what national health surveys indicate that adults in this age group have gained over the same period.
The authors concluded that the reduction in work related caloric expenditures could have been compensated if the minimum 2008 federal recommendations for physical activity had been met. Just 150 minutes per week of moderate intensity activity (21 minutes a day) or 75 minutes per week of vigorous intensity activity (11 minutes a day). National health statistics indicate that fewer than 25% of U.S. adults achieve this goal.
The Bottom Line
While the news has been dominated with how our shift from a manufacturing to a service economy has negatively affected jobs and employment, this is the first study I’ve seen that suggests how this change has negatively affected our waistline too.
If your job requires that you sit at a desk for long periods of time, then it becomes increasingly important that you engage in some sort of physical exercise outside of work.
As this study demonstrated, you don’t need to burn significantly more calories to shift things in your favor. Whether it’s parking a bit further away in the lot, using the stairs or walking at lunchtime, anything physical you do will keep you one step ahead of the calorie game.
When I worked in Boston and New York, I figured out that by walking back and forth to the train station in the mornings and evenings, I easily burned an extra 200 calories a day. Now that’s the kind of addition I can understand!
David H. Rahm, M.D. is the founder and medical director of The Wellness Center, a medical clinic located in Long Beach, CA. Dr. Rahm is also president and medical director of VitaMedica. Dr. Rahm is one of a select group of conventional medical doctors who have education and expertise in functional medicine and nutritional science. Over the past 20 years, Dr. Rahm has published articles in the plastic surgery literature and educated physicians about the importance of good peri-operative nutrition.