This past Saturday, as I stood on the sidelines of my daughter's soccer game, it struck me: I was looking at a group of 9-year-olds of all sizes. Some, like my daughter, are tiny spitfires of energy. Others have already hit a growth spurt and are nearly my height (all of 5-foot-5). But while there is no uniformity in height, they all have one thing in common: they are all relatively thin.