12,568 runners were tracked for 9 years. Most gained fat and increased waist size. Here's why

A 2006 study backs this up. In the study, 12,568 runners were tracked for 9 years. The majority of the runners gained body fat and increase waist circumference during that time period, even if they never quit running. Especially the men.

The runners who gained the most fat around their waists were the ones who decreased their mileage, mainly due to the inevitable running injuries. But get this: even runners who maintained or mildly increased their mileage got fatter.

The only runners who didn't get fatter were the ones who significantly increased their mileage, most by 3 times as much running per week.

In other words, unless you get to near-marathoner level, running makes you fatter as you age. And if you ever have to quit or cut back due to life's demands or injury, your endurance-exercise adapted body will quickly pack on body fat and your waist size will dramatically increase .... http://tnation.t-nation.com