[dejb]

> Within a few months, most of the participants had resorted to exercising as much as they chose to. That left researchers with a slightly different data set than they had planned for...

This self-selection tends to invalidate the study I think. It is possible that the people who chose not to exercise much were exactly the ones who needed it the most. The people who chose to exercise a lot are more likely to have been fitter in the first place.

[edw519]

This self-selection tends to invalidate the study

Not to mention the fact that almost no treatment of a "study" in popular media distinguishes between correlation and causation. There is a difference, a fact lost on almost everyone these days.

[I lost .4 pounds last Thursday commenting on Hacker News. Therefore, typing causes weight loss :-) ]

[kingkongrevenge]

If I read correctly all they even looked at was light treadmill exercise. Yeah, you have to do that for hours to impact the body. You have to burn through glycogen stores to really get anywhere. It's different for more intense sessions and strength training, though. They can be short and have impact beyond calorie arithmetic.