Weighing the Evidence on Exercise

Quoting Gretchen Reynolds:

The newest science suggests that exercise alone will not make you thin, but it may determine whether you stay thin, if you can achieve that state. [...]

The exercising rats metabolized calories differently.  They tended to burn fat immediately after their meals, while the sedentary rats’ bodies preferentially burned carbohydrates and sent the fat off to be stored in fat cells.  The running rats’ bodies, meanwhile, also produced signals suggesting that they were satiated and didn’t need more kibble. ... Running had remade the rats’ bodies so that they ate less.

The article has lots of interesting stuff in it from different studies, many involving humans rather than rats.  The main idea is that yes, exercise is important for weight control, but not necessarily in the way you’d expect.