Two clinicians from Christiana Care Health System in Wilmington, Del., weighed in on the findings. They suggested that healthy workplace behaviors -- such as light lunches and midday walks -- may help balance out the negative effects of sitting at a desk all day.

Many people "don't really have the option of being that inactive on weekdays," said Dr. Omar Khan, medical director for community health at Christiana Care. "Weekends are a whole different matter. There's a big opportunity to be healthy -- or, as many of us tend to be, fairly unhealthy. With a two-day chunk of potentially being a couch potato, anything we do in that space can be fairly significant."

Karen Anthony, senior program manager for community health at Christiana Care, suggested that moving around for an extra 20 minutes on the weekends -- which seemed to spur measurable weight loss in study participants -- could lead to even more activity.

"Twenty minutes is a fraction of your weekend," she said. "It doesn't take a whole lot of extra movement to see that result."

Seems like lazy ANYTHING boosts body fat. 

When you say "20 minutes"... is that CUMULATIVE? Like walking from the couch to the bathroom 20 times?