You'll want to sit down for this—wait, you probably already are. Fewer jobs requiring even moderate physical activity contributes to workers burning 120 to 140 fewer calories on the job than they did in the '60s, reports USA Today. During an average workday, men burn an average of 142 fewer calories, women 124, says a study by top national physical activity experts.
"We have transitioned from jobs that primarily involved doing physical activity on our feet to ones where most of us make our living while sitting," says the lead author. It's a contributing factor to the nation's obesity epidemic that dovetails with another: "Our eating habits have changed," says a Penn State nutrition professor. "Portion sizes are huge, we're eating more food away from home, high-calorie foods are everywhere. We have opportunities to eat all day, and we're doing it." (Read more calories stories.)