(CNN) -- Roy Pickler lay on the floor, dripping with sweat, as trainer Bob Harper quipped, "You look like you got run over by a reindeer."
Pickler's job as a professional Santa was a constant joke on the latest season of "The Biggest Loser." With his long white beard and protruding stomach, the 63-year-old looked every bit the part he played.
By the time he was voted off the show, Pickler had lost 88 pounds. During his elimination interview, he donned a Santa hat and told viewers his toned physique wouldn't stop him from bringing Christmas joy to children.
"The world is going to have to change their acceptance of what Santa looks like," Pickler said. "Santa is a role model, and kids don't want to have a role model that's fat."
Since 1980, obesity rates among children and adolescents have almost tripled, according to the Centers for Disease Control and Prevention. Approximately 12.5 million children age 2 to 19 are obese; that extra weight can lead to serious health problems, including type II diabetes, cardiovascular disease and psychosocial issues such as peer discrimination or poor self-esteem.
Children learn healthy (or unhealthy) habits from those they admire. And Santa is one of the most recognizable figures in America.
For at least a month every year, he appears on billboards, storefronts and TV commercials. Millions of kids stand in line to sit on his comfortably padded lap and whisper secrets in his ear. They write letters to him, sing songs about him and read stories about him.
We worry about the effect fast-food advertisements have on students in school. With all his free publicity, should Santa still be fat?
"Let's put it this way," registered dietician Beth Kitchin said with a laugh. "I don't think Santa should be skinny."
There are a lot of other markers to consider in measuring health. Research shows that people can have a higher body mass index and still be healthy, Kitchin said. One can assume Santa is pretty active, wrangling hundreds of elves and nine reindeer every year. And his cheery disposition says a lot about his stress level, which could relate to low blood pressure.
Of course, Santa does have a penchant for sugary treats. One fan estimated the big man eats more than 5,000 tons of cookies on Christmas Eve alone. If Santa isn't diabetic, Christmas magic really does exist.
A 2009 study published in the British Medical Journal determined that Santa could very well be a "public health pariah." The light-hearted research by Nathan Grills of Monash University in Australia found a correlation between countries that recognize Santa and a high rate of childhood obesity.
Santa's weight is a longstanding tradition, said Tom Kliner, founder of Santas Across the Globe and the Fraternity of International Real Bearded Santas. The character originated with St. Nicholas, who lived in Turkey during the fourth century. Nicholas was a wealthy young bishop who started giving away all his gold after his parents died.
"Back in those days, extra weight was a sign of wealth and affluence," Kliner said.
Hollywood used to have a set of numbers -- waist circumference, face shape, beard length -- that Santas were supposed to adhere to, Kliner said. But around the world, the legendary giver comes in all shapes and sizes. Coca-Cola's Santa, whom many in America try to emulate, is very round: round face, round nose, round stomach. The Santa imitated in Europe is a thinner man with more squared-off features.
Kliner said he sees Santa as more of a public figure than a role model. "I've never seen anybody aspire to become Santa Claus."
Changing Santa's iconic image would be hard, said Meg Cox, author of "The Book of New Family Traditions." Comfort and security come with seeing the same character year after year.
"We carry these traditions forward from our childhood," she said. "Some of us are pretty emotional about them. And yet I think there's nothing wrong with having a sense of play about it."
If you want Santa to be skinny, Cox said, make it happen: Tell your kids Santa is tired of eating cookies, and leave an apple out instead.
"Having your own take on Santa might be the ultimate personalized Christmas."
It's possible our culture is already changing. Santa races are becoming as much of a tradition as candy canes and Christmas lights. Kids are finding active video games under the tree alongside step counters and organic cookbooks for Mom or Dad.
Pickler recently called a couple of companies he has contracts with and asked whether they were OK with a trim Santa.
"They both said, 'We want you just the way you are. Your idea of a healthy Santa is the one we want to go with.' "
Since "The Biggest Loser" finale, Pickler and his wife, Chris, have spoken to kids across the Midwest about nutrition and exercise. Pickler often walks in to schools dressed as Santa Claus and then takes off his suit, Superman-style, to reveal his new fit self.
In an upcoming documentary about Santas titled "They Wore a Red Suit," Pickler implores his colleagues around the country to get fit.
"We cannot use (our role) as an excuse, because it influences kids in the wrong direction," he said.
Maybe one day, instead of a belly that shakes like a bowl full of jelly, Santa will have a six-pack. Maybe his cheeks will glow not from the cold but because he's consuming the recommended doses of omega-3 fatty acids. Maybe Mrs. Claus will take up gardening. (Granted, that would be hard to do at the North Pole, but surely the elves can build a greenhouse or two.)
Eventually, in addition to being a role model for the Christmas spirit, our beloved St. Nick could become a healthy role model for kids.
Until then, save some cookies -- Santa Claus is comin' to town.