NEWARK — Governor Chris Christie, who once famously called himself ‘‘the healthiest fat guy you’ve ever seen,’’ disclosed Tuesday he had secretly undergone weight-loss surgery, a major new step by the potential Republican presidential contender to address both his health and a political vulnerability.
The stakes are high for Christie, with medical professionals and campaign strategists alike suggesting there is no more serious barrier to his personal well-being and national ambitions than his weight.
It’s not about politics, he said. It’s about turning 50 and wanting to be around as his children grow up.
‘‘This is a hell of a lot more important to me than running for president,’’ Christie, a father of four, said at a news conference in Newark. ‘‘This is about my family’s future.’’
Christie, who appeared thinner than he did earlier this year, said he decided around the time of his birthday in September to have the surgery and initially planned to have it done in November. But Superstorm Sandy’s destruction in New Jersey pushed back the procedure until February. In the operation, a band was surgically placed around his stomach to restrict how much food he could eat.
Christie has not previously disclosed his weight, and he did not on Tuesday. But it has been an issue throughout his political career. Comedians have often made fun of it, and in interviews with David Letterman, Oprah Winfrey, Barbara Walters, and others, Christie has both joked about the issue and said solemnly that he was trying to shed pounds.
During a February appearance on ‘‘The Late Show with David Letterman,’’ the governor pulled out a doughnut and said his girth was ‘‘fair game’’ for comedians.
Over the next few days, he was asked repeatedly about his weight. At one point, he said he had a plan. ‘‘Whether it’s successful or not,’’ he said, ‘‘you’ll all be able to notice.’’
The next day, he responded angrily to comments from a former White House physician who said she hoped he would run for president but worried about him dying in office. The governor said the doctor should ‘‘shut up.’’
Ten days after that, on Feb. 16, Christie had the surgery. He said the operation lasted 40 minutes and he was home the same afternoon. He was back at work on Feb. 19 for a full day of events.
Christie, who is in the midst of a reelection campaign, said he has been eating less because he hasn’t been as hungry. He also has been working out with a personal trainer.
He said he had told only a few top staffers — not his communications office or campaign staff — and his communications director was caught by surprise Monday when a New York Post reporter asked if he’d had the procedure. The Post first reported the surgery on Tuesday. Christie said he had used an alias at the hospital.
Christie said he never intended to make a public announcement and that he was ‘‘not going to be the guy who writes a book’’ about losing weight.
The Republican, who has been a fixture in the national media spotlight, said the scrum of reporters at his news conference was ‘‘silly’’ and ‘‘ridiculous’’ at a time when there are other things going on.
He said he tried other ways to lose weight for years, but none seemed to work.
‘‘It’s not a career issue for me; it’s a long-term health issue for me,’’ he said.
Still, it’s a way to confront a significant hurdle in his indisputable quest to emerge as a key leader in the Republican Party. He’s in the top tier of those considered potential contenders for the presidential nomination in 2016.
Weeks after the surgery, Christie launched an aggressive national fund-raising tour, fueling speculation that he is laying the groundwork for a White House bid.
In a country facing an obesity epidemic, more than 220,000 stomach-reducing procedures of various types are performed each year.
Christie had gastric band surgery. It is best known by the brand name Lap-Band.