NBC's Al Roker (search) reports on his health since his gastric bypass surgery (search), and the potential dangers and benefits involved in the procedure, in an hour-long special to air Friday night on "Dateline NBC." (search)

Roker, the weatherman on the network's "Today" Show, underwent gastric bypass surgery two and one-half years ago.

"For anybody who thinks that this is a magic bullet — you do this and it's done. You're making a mistake. It's not," he says.

In the four-part report, "Weighing the Risks," Roker talks to teens, parents and a physician about some possible dangers, and whether teens have a tougher time dealing with emotional and physical changes that come with the surgery.