Dr. Mehmet Oz
He's one of the best-known doctors in the country, thanks to his position as chief medical correspondent for CNN. Dr. Sanjay Gupta talks to Dr. Oz about childhood obesity, reporting from war zones and balancing medicine with the media.

A fellowship in the Clinton White House led to a meeting with the head of CNN, and ultimately to Dr. Gupta's position as a medical correspondent. He felt that working in the media would be a good fit—it would allow him to report medical news, as well as give viewers deeper knowledge. "With knowledge, you're giving something that's more contextualized and pertinent to [viewers'] lives," Dr. Gupta says. "These are the things that really hit home for people, that touch them on a personal level."

Dr. Gupta has reported from hot spots like Iraq and New Orleans in the aftermath of Hurricane Katrina. He says that, for him, Katrina was a defining moment in terms of blending his worlds of medicine and media. Covering Katrina wasn't even in his plans until he started getting e-mails from friends who were stranded in New Orleans's Charity Hospital. "They weren't evacuated, they had no power and very little food," Dr. Gupta says. "It was being reported that they had been evacuated, but they weren't. That meant they were forgotten." He flew to New Orleans with a camera crew and started reporting; within 30 minutes, helicopters started landing to pick up patients.

Working in Iraq with the "Devil Docs," a U.S. Navy unit that supports the Marine Medical Corps, was another defining experience for Dr. Gupta. Because the medical teams didn't have neurosurgeons on staff, he was asked to operate several times on soldiers with significant head wounds. "Organizations like the Devil Docs are saving so many lives right now," Sanjay says. "They stay with the troops and take care of the injured as soon as they're injured. They're saving more lives—there are more survivals, but more injuries."

Dr. Gupta is tackling this country's obesity epidemic with CNN's Fit Nation campaign. In a series of town hall meetings across the country, he challenges communities to do something about weight. "We talk about [obesity] a lot, and I think people get it, but why is it happening and what do we do?" Dr. Gupta says. He hopes that the message people take away from the meetings is to become advocates about how to solve the obesity problem. "The [United States] used to be a vibrant, fit nation," Dr. Gupta says. "We went from that to one of the fattest in the world. The bad news is that it happened. The good news is that it can be reversed."