It’s not an unrelated coincidence: During the past 50 years, most jobs have become less physical and obesity rates are rising. Today, most people spend most of their time at work sitting at a computer or talking on the phone, and as a result they burn fewer calories—at least 150 fewer per day, according to a 2011 study conducted by the U.S. Bureau of Labor Statistics. Less activity at work has been identified as a key contributor to the rise of obesity in America.