Paul Greenberg of Frontline: Why seafood alone is plenty nutritional

A scene from the Frontline "The Fish on My Plate" preview (YouTube.com)

Paul Greenberg is the author of Four Fish and American Catch, has been a lifelong fisherman and now writes the documentary, “The Fish on My Plate.” He tells John why he set out to write this story, and to eat nothing but seafood for one year.