Ok, so once again we can complain that scientists are telling us what we already know: exercise can keep us from gaining weight. And in this case, simple physical activity, brisk walking or cycling, could do the trick.
But the interesting--and really encouraging-- thing about this news published in the Archives of Internal Medicine is the news for women who are seriously overweight or obese: you benefit even more than women of 'normal' weight who biked to keep weight off.
And here's the best part of all for those who find time or motivation is short: even 5 minutes a day makes a difference.
The bottom line: don't just sit there, move something.