New Jersey Gov. Chris Christie, R, who has struggled with his weight, poked some fun at himself in his first appearance on CBS's "Late Show with David Letterman."

As the comedian apologized for past barbs, Christie pulled a doughnut from his suit pocket and began munching.

"I didn't know this was going to be this long," he said after he licked his fingers, brushed off crumbs and then wiped his mouth.

Christie, who has been on the wrong end of Letterman's often-biting Top 10 lists, said that during a physical exam ahead of his 50th birthday in September, his cholesterol and blood sugar levels were both within normal ranges. His wife and four children prod him regularly to lose weight, even joking he may one day want to buy smaller pants, Christie said.

"I'm basically the healthiest fat guy you've ever seen in your life," he told Letterman, who suggested he should make it the slogan for his re-election campaign.

Christie walked onstage to "Thunder Road," by New Jersey native Bruce Springsteen, his favorite musician. The governor, who has become a media sensation, sang that song last year during an appearance on NBC's "Late Night with Jimmy Fallon," and also did a comic bit on the network's "Saturday Night Live."

In 2011, while Christie considered for a bid for the White House, Letterman estimated his weight at 400 pounds.

"I've made jokes about you, not just one or two," Letterman said during Monday's show. "Is it an issue or is it not an issue? And you tell me how you see things."

Pausing in his doughnut repast, Christie responded, "I only care if you're funny.

"I mean, from my perspective, if the joke is funny, I laugh, even if it's about me," the governor said. "If it's not funny, I don't laugh. But I've never felt like it was, you know, anything that really bugged me all that much."

Pressed to say how many of the jokes he thought were funny, Christie replied, "about 40 percent -- roughly." Later, he read some of his favorites, and as he did, Letterman took a bite of the same doughnut.

Among the governor's Top 10 were "Chris Christie turned 50 -- he blew out the candles on his cake, and he wished for another cake," and "A billion dollars will be spent on potato chips for Super Bowl Sunday, and that's just at Governor Christie's house."

The governor told Oprah Winfrey on her television show a year ago that he worries about his weight and said the struggle began 30 years ago, when he stopped playing sports in school. Christie also told Winfrey that he had been working with a dietitian and exercising more regularly.

New Jersey Governor Chris Christie gives his State of the State address in the assembly chamber in Trenton, N.J.
New Jersey Governor Chris Christie gives his State of the State address in the assembly chamber in Trenton, N.J. (Reuters/Carlo Allegri)
"Are you on a diet now?" Letterman asked him. "Obviously not!" Christie said, pointing to the doughnut. "Just blew it."

The first Republican elected New Jersey governor since 1997, Christie became a national figure for raising contributions to pensions and benefits, vetoing tax increases against millionaires and leveling insults at critics during confrontations.

Last year, gossip website TMZ.com showed video of him shouting at a detractor who used profanity as Christie was buying an ice cream cone on the Seaside Heights boardwalk with his kids and their friends. Letterman set the confrontation to "fat guy music" and said that angering Christie is like "crossing a rhino."

In a December interview on the ABC network, Christie told Barbara Walters that his response to damage left by Hurricane Sandy showed his weight hadn't slowed him down and that it shouldn't bar him from seeking the presidency, if he decides to run for the office.

"Had fun on Late Show last night," the governor said to his 336,276 followers on Twitter Tuesday morning. "Maybe Dave will finally ease up on the jokes? Probably not."