(CBS News) When New Jersey Gov. Chris Christie sat down with David Letterman Monday night, Christie said it was OK to laugh about his weight. But at a news conference on Tuesday, Christie admitted it's not just a joke. His obesity could be a factor if he runs for president.
Dr. Connie Mariano, who was a White House physician, said, "When somebody who has morbid obesity is running around, he's probably got heart disease and continued stress and eventually will have a heart attack. So that's the time-bomb theory. It's bound to happen if he continues that lifestyle."
Mariano was physician for former President Bill Clinton, another president whose fondness for all things fried was fodder for late-night scrutiny, in 2004 Clinton underwent quadruple bypass surgery, and he's recently become a vegan -- if you can believe that -- to try to reverse the effects of heart disease.
No one expects Christie to follow Clinton's diet. Christie said Tuesday that he's not unlike a lot of Americans who are working on their health. He told the press, "I'm making the best effort I can. And sometimes I'm successful, and other times I'm not. And sometimes periods of great success are followed by periods of great failure."
But Christie may not be as unhealthy as he looks. In a study released last month, researchers found that while people who are obese have a higher risk of death -- body mass index is an imperfect measure of mortality. Factors like blood pressure, cholesterol, and blood sugar must be considered.
Christie told Letterman his cholesterol and blood sugar levels are both normal, adding, "I'm basically the healthiest fat guy you've seen in your entire life."
Despite the jokes, Christie says anyone who struggles with weight is always working on a weight loss plan. He said, "Be assured, be assured, there is a plan. Whether it will be successful or not, you'll all be able to notice."
During the presidential primaries, many Republicans clamored for Christie to enter the race, and his leadership style during Hurricane Sandy has only increased his popularity, especially in his home state. A recent Quinnipiac University poll found 74 percent of New Jersey residents approve of Christie. And no matter how much he weighs and whether his weight plan works, Christie remains a frontrunner in any 2016 campaign discussion.
For Jan Crawford's full report, watch the video in the player above.