Couch potatoes, rejoice! A new study suggests hours spent lounging in front of the television aren’t necessarily to blame for rising obesity rates.

European researchers reviewed twenty years’ worth of data from the Netherlands, the United States and the developing world to see how dietary habits and daily activities have changed over time.

The bottom line? People are as active as ever, but larger meal sizes may have gradually supersized American and Dutch waistlines.

The scientists used a technique called the “doubly labeled water method” to assess each participant’s overall metabolism, thereby sidestepping the tendency of some people to fudge their daily habits on paper so they’ll look healthier.

Volunteers imbibed trace amounts of water engineered with a particular molecular signature. Researchers could determine how much energy the volunteers were using by tracking the disposal of these molecules in urine samples.

The study found that Americans, Europeans and residents of developing countries expend about the same amount of daily energy as they have for the past twenty years.

So why has obesity tripled in the United States over the same time span?

Researchers blame overeating.

The discovery may relieve some of the guilt felt by couch potatoes far and wide.

Our forebears didn’t use the time we spend in front of the T-V or computer running marathons, cross training, or doing something equally healthy.

But they probably weren’t pounding the chips, either. From now on, reach for a healthy snack.

Better still, have someone else get it. Why leave the couch?