What does this have to do with health and fitness? Everything. As I have argued elsewhere, we are not simply the end products of fixed-in-place genes that determine, for example, how much we weigh. Nor are we defined only by our early childhood experience. It is way more complex, and there is much room for variation in our health and lifestyle. Now, with the new respect in medical science for complexity and subtlety, there may even be room for ???willpower.??? Admittedly, that is stretching the point, but I firmly believe that there are far more ways to impact our personal destinies than my former colleagues in psychiatry have acknowledged.