Chew gum to lose weight?

The product: Contestants on the current season of NBC’s “The Biggest Loser” have been taking a slightly offbeat approach to shedding pounds. In addition to sweating on treadmills and sticking to near-starvation diets, they’ve been chewing gobs of gum -- Wrigley’s Extra sugar-free gum, to be exact.

Product placement on reality TV is nothing new; even the castaways on “Survivor” have enjoyed regular doses of Doritos. But on “The Biggest Loser,” the gum has become a prominent part of the show. Trainers and nutritionists assure the “losers” -- and the viewing audience -- that gum can curb appetite, prevent snacking and provide an edge in the weight-loss game.

Gum-chewers have long known that a stick of spearmint or Juicy Fruit can be a pleasant diversion, but this is the first time that a major company has promoted gum as a weight-loss aid, says Kelly McGrail, senior director of Wrigley corporate relations.

The claims: A television ad that runs during “The Biggest Loser” sums up the new promise with a memorable tag line “Go from ‘nice gut’ ‘to ‘nice butt.’ ” The ad also calls Extra gum the “long-lasting 5-calorie snack to help reveal the new you.”

According to Gil Leveille, executive director of the Wrigley Science Institute, a “global advisory panel of experts” on matters pertaining to gum, chewing the stuff can help dieters in two ways. “Chewing gum can help relieve stress, and mindless munching is often stress related,” he says. The mere act of chewing, he adds, can also curb appetite.

The bottom line: If you’re counting calories, a stick of gum is miles better than a Twinkie. A stick of Wrigley’s sugar-free gum contains 5 calories, about as many as a small stick of celery. A stick of regular gum typically has about 10 calories -- still not a lot, especially if you’re the type that makes a single stick last for an hour.

A recent study funded by Wrigley suggests that gum really can help people go easy on higher-calorie snacks. Researchers at the University of Liverpool fed 60 young adults lunches and snacks on four separate days. On half of their visits, the subjects chewed two sticks of gum (either regular or sugar-free) in the hours after lunch. The subjects said they felt less hungry after chewing gum. And when they were offered cookies, chips and candy three hours after lunch, the gum-chewers consumed an average of 36 fewer calories. The type of gum didn’t seem to make any difference.

If gum chewers could get the same results day after day, the small shortfall in calories could really add up to significant weight loss, says Richard Mattes, a professor of foods and nutrition at Purdue University. Unfortunately, he says, it’s probably impossible to “trick” the appetite on a daily basis. “It wouldn’t work indefinitely,” he says. “The body corrects itself.”

Mattes’ own study of 47 people didn’t show any connection between gum chewing and appetite. After eating lunch in the laboratory on three different days, the subjects were told to either chew sticks of gum when hungry, chew at a set time of day or avoid gum altogether. When interviewed later, they said the gum had no effect on their hunger or snacking habits. (Unlike the Liverpool study, researchers didn’t directly measure food intake.)

Gum has one proven way to melt serious pounds. As recently reported in January in the British Medical Journal, a 21-year-old woman who chewed about 15 sticks of sugar-free gum each day developed out-of-control diarrhea and lost 20 pounds in just eight months. (She weighed only about 110 pounds to begin with.) Researchers identified the culprit as sorbitol, a natural sweetener found in many types of sugar-free gum, including Wrigley’s, as well as other sugar-free products.

They noted that a daily dose of 20 grams of sorbitol -- the equivalent of 16 sticks of sugar-free gum -- would likely cause diarrhea in about half of all healthy people.

Appetite expert Paula Geiselman, an associate professor of psychology at Louisiana State University who receives some funding from Wrigley, believes gum -- in moderation -- can be helpful to dieters. “I would recommend that people give gum a try, as long as they’re not allergic,” she says. Having something flavorful in the mouth likely calms the appetite, she says. And if nothing else, she adds, the mere act of chewing can burn 11 calories an hour. Not quite up there with sweating on a treadmill -- but it’s something.

Is there a consumer product you’d like the Healthy Skeptic to examine? E-mail the details to health@latimes.com.