Source: http://www.npr.org/blogs/health/2014/08/...

We're constantly hearing messages that we're eating too much and not moving around enough. Now researchers suggest that we're actually not eating more than we did 20 years ago, it's that we're much less active. And that includes not just middle-aged workers tied to their desks, but also young men and women who spend their days sitting in front of their laptops.

To try to figure out the impact of food versus activity, Dr. Uri Ladabaum, a professor of medicine at the Stanford University School of Medicine, looked at federally collected health data from the NHANES program from 1988 and compared it to 2010.

He expected to find people eating more over the past two decades. But instead, he found that caloric intake remained about the same, "which may seem a little surprising given the trends in portion size and the popular belief that we're eating more and more," he said.

For example, it could well be that we were already eating too much back in 1988, compared with earlier decades. Even so, Ladabaum found the biggest changes were in the amount of physical activity."It may well be that we're eating too much, but it doesn't seem that we are accelerating our caloric intake," Ladabaum added.

Back in the 1980s, 80 to 90 percent of people reported doing at least some physical activity in their leisure time. But now, up to half of Americans say they are not active at all.

And that's likely an underestimate, Ladabaum says, because people tend to overestimate their activity.