If I were you, I wouldn't take this to the bank.
However, you may find this article provocative. It's from the New York Times physical education writer Gretchen Reynolds about how a study on lab rats yields some perspective on how exercise protects us from fatty food consumption.
Now my goal is not to reduce anyone to "lab rat" status here, but it illustrates the point that a little extra exercise certainly can't hurt . . . especially when we're taking in more high-calorie food than we should.