Obesity means today's teens will have shorter lives than parents

A St. Louis Post-Dispatch article, which calls the problem of overweight kids a "crisis", leads with this fact:
Today's teens are the first generation of Americans projected to lead shorter lives than their parents.

Blame fat.

The obesity rate for adolescents has tripled in the past 20 years. And more and more of these kids are hitting extreme ends of the scale, stretching to levels of severe obesity, morbid obesity and super-obesity unimaginable in generations past.

Nearly one in three children and teens is overweight today. One in six is obese.