Study: few doctors telling parents their kids are obese

Childhood obesity has been called a national epidemic.  One in three American children are either overweight or obese.  To make matters worse, many parents aren't even aware their kids have a weight problem because many doctors fail to let them know.

Alina Cho and Carol Costello speak with CNN senior medical correspondent Elizabeth Cohen to discuss what parents can do to be more empowered about their children's weight.