Fat is the new win.

Jet coach Rex Ryan, who hates losing weight almost as much as he hates losing football games, started the season determined to shed many of his 350 pounds.

The diet, like the Jets’ early good fortune, did not last long.

But with his team on the cusp of the Super Bowl, Ryan seems to have found the recipe for success, and he’s eating a lot of it.

Although he once feared his 7,000 calories a day were holding him back from earning a head-coaching job, he is now going with his gut.

The coach celebrated Sunday’s triumph over the San Diego Chargers by scarfing down a cheesesteak and a beer on the charter flight back home. He was then offered a choice of barbecue chicken, flank steak or a Cobb salad.

“I have never heard him order a Cobb salad,” a source told The Post. “And I don’t think you would be slandering him to say he is a beer guy.”

After most games, Ryan, 47, and his wife, Michelle, eat heartily at a diner in New Jersey.

The coach’s favorite cuisine is Mexican — his assistants call it “Rexican” — and Ryan dined Friday night in San Diego at Café Coyote, whose menu features the adjective “large” before many of its south-of-the-border offerings.

During training camp last July, Ryan said that moving to Jersey had led him to pack on a few dozen extra pounds, noting, “There are so many Italian restaurants.”

Ryan has taken his share of ribbing about his girth.

While dieting a few years ago, an assistant spied Ryan toting a pizza to his hotel room. When confronted, Ryan claimed it was for his son Seth.

But the next day, when the assistant asked Seth about the pie, the boy replied, “What pizza?”

“He’s having a hard time living that story down,” one coach laughed.

The big fella has gone on several weight-loss programs to raise money for his children’s teams, but admits the pounds always return.

“There’s not too many fat guys that are coaches,” he said in 2007. “But I don’t see how your weight can make you a better coach.

“But I guess if you’re the face of the franchise, then that is important as well.”

Going into Sunday’s game, let’s hope the Indianapolis Colts are the biggest losers.

jeremy.olshan@nypost.com

