TEENAGERS TODAY ARE surrounded by images of slenderness. They turn on the television or pick up magazines and see beautiful people who are also thin. The diet industry is a $40 billion business and growing. Magazines are filled with articles on counting calories and losing weight, not to mention advertisements glorifying thin bodies. Both boys and girls feel society's pressures to have perfect bodies. But there is a difference. Boys are given more leeway in how they look. They are taught to value their bodies for what they can do and themselves for what they can achieve. Not that boys are problem free. They can develop eating disorders when they try to mold their bodies to reach a specific sports ideal. In addition, men today are expected to be slimmer, more muscular, and more youthful. And like women, increasing...