WASHINGTON — In this season of ever-present Christmas cookies, an unlikely figure is leading the offensive against America’s obesity epidemic. The beard on his double chin is as white as snow, and when he laughs, his belly shakes like a bowlful of jelly — and that, as Ernest Berger sees it, is the problem.

As president of the volunteer group Santa America, Berger has been nudging some of his more corpulent colleagues toward a different model of Santa. He wants his fellow members of the Claus family to give themselves the gift of less girth.

He calls it “a matter of self-preservation” that will also help children to whom Santa Claus is a roly-poly role model.

“I’m pushing to reduce the size of Santa by 25 percent,” Berger says from his home in Daphne, Ala. “We’re gently and relentlessly focused on getting these men to be positive about fitness and wellness and reducing their weight.”

This battle of the bulge has been raging quietly within the Santa community, which is made up of an estimated 4,000 professional Santas who congregate at annual conventions, chat year-round on Claus-centric online message boards, spend thousands on customized outfits and perform everywhere from shopping malls and military bases to homes and hospices.

In some Santa circles — typically, the ones with the largest circumferences — the idea that Santa Claus should consider swapping sugar cookies for carrot sticks has been about as popular as vegan eggnog.

“Some of the obese men are saying, ‘Don’t go there; why not just go get a pizza?’” Berger says. “They feel it’s not something Santa America should be emphasizing.”

A half-dozen super-heavyweight Santas contacted for this story declined to comment. “In many ways, it’s the third rail in the world of Santa,” Berger says.

Nicholas Trolli, president of the Amalgamated Order of Real Bearded Santas, says there was no shortage of blowback when he pushed for a slimmer Santa a while back. Some Santa lovers “told me to shut up; like, who am I to decide what Santa’s weight should be?” says Trolli, who is clinically obese at 5-foot-10, 270 pounds and has members who easily top 400 on the scale. Trolli says weight loss is no longer an active initiative for his group, though he says he still thinks Santa could stand to come down a few sizes.

Berger estimates that one-third of professional Santas in the United States are obese, roughly mirroring the prevalence of obesity among American adults. Another third of Santas are overweight, says Berger, who includes himself in that category.

The rest of the Santas are fit, but you might not know it, since many wear padding under their big, red suits to create the illusion of a massive midsection. Berger wants to see Santa lose that fake fat, too, and get back to where he might actually fit in a chimney again.

Declaring a fatwa on excessive Santa fat is daring to tinker with a cherished cultural icon that dates to the Great Depression, when Santa was drawn as a jolly fat man for a famous Coca-Cola advertising campaign, his paunch intended to symbolize better, more prosperous times. Although Santa had been presented in varying sizes before then, Coke’s ads made him permanently porcine, at least in American culture. (He was, and still is, more svelte in other parts of the world — plus Los Angeles, where a Hunky Santa, a chiseled, shirtless Claus alternative “reflecting L.A.’s healthy lifestyle,” has a mall gig.)

But as the obesity epidemic has swollen, some public health experts have cast an increasingly critical eye on Santa’s sprawl. Two years ago, acting Surgeon General Steven Galson said Santa’s corpulence was setting a bad example. His remarks prompted howls of protest, with more than a few people accusing Galson of being politically correct in trying to make Santa physiologically correct.

An opposing expert opinion comes from Andrea Vazzana, a psychologist who specializes in weight management at New York University’s Child Study Center. She says a svelte Santa “would be great for Santa, but I don’t think children would benefit. The children who are believers in Santa, in that age range, they don’t have a whole lot of say in what they eat.”