Holiday Weight Gains Small, but Lasting
People gain much less weight than commonly believed during the holiday season that stretches from Thanksgiving’s pies to New Year’s excesses, according to a federal study of 195 adults published today.
But that encouraging word was tempered by another finding: Despite health-club come-ons and springtime epidemics of bathing suit dread, the subjects who gained a festive pound or less tended not to lose it over the course of a year, setting themselves up for substantial weight gain or even obesity in the future.
In the study, described in the New England Journal of Medicine, researchers weighed the volunteers in the fall, winter and spring. Fifty percent of the subjects gained an average of a pound over that period. Of those, fewer than 10% put on five pounds or more, and they tended to be overweight to begin with.
Also somewhat unexpected, given pervasive holiday complaints about too much punch and too many cheese balls, 50% of the subjects did not gain any significant weight. Regular physical activity was largely the reason, said the researchers, who are based at the National Institutes of Health.
The study, apparently the first to assess seasonal weight gain in a rigorous way, debunks the notion that Americans typically put on five or more pounds over the holidays, downgrading it to a myth, researchers said. Though the researchers cited news reports and press releases disseminating that figure, they turned up no reliable academic or government study to back it up.
Most important, weight experts said Wednesday, the study sheds new light on the great Mystery of the Expanding Waistline, suggesting that a seemingly negligible seasonal gain can persist, notwithstanding exercise gear from Santa and Jan. 1 resolutions.
“That is a core finding and may be important in understanding the continuing weight gain we see in the American population over time,” said Dr. W. Stewart Agras, a Stanford University psychiatrist specializing in weight disorders.
“Upping one’s activity level may be the antidote to this, if a somewhat painful one,” he added. Indeed, the 45 volunteers who reportedly increased their physical activity over the holidays had the least weight gain. Several actually lost a bit.
As previous research has shown, being obese or seriously overweight increases the risks of health problems such as cardiovascular disease and diabetes. And preventing weight gain, difficult though it may be, is easier than losing weight, health experts and amateur scale watchers agree.
About 30% of the U.S. population is overweight and roughly 22% more is obese--defined as 20% or more above the ideal weight. Though the precise definition of a healthy weight is open to debate, authorities generally define it as a body mass index between 20 and 25. To calculate a body mass index, divide weight in kilograms by height in meters squared. Accordingly, a healthy weight range for a 5-foot-5 person is 120 to 150 pounds. (More on body mass index can be obtained on the Web at https://www.shapeup.org/bmi/.)
No one disputes that the six-week holiday season beginning in late November is fraught with metabolic perils. Dropping temperatures and waning daylight threaten exercise routines. Devilish holiday platters tempt. Meanwhile, the basic mammalian drive to store energy as fat for winter’s scarcity may kick in.
The study does not pinpoint exactly why some volunteers gained weight. Still, one of the study’s six co-authors said it was significant that the volunteers tended not to gain weight in late winter, when the celebrations tapered off. “It’s likely that holiday behaviors such as overindulging in food and drink did contribute” to the weight gain, said Dr. Susan Yanovski, executive director of the National Task Force on the Prevention and Treatment of Obesity.
The yearlong study, begun in September 1998, relied primarily on volunteers from the National Institutes of Health in the Washington suburb of Bethesda, Md. It employs 19,000 people, from groundskeepers to Nobel laureate scientists. The subjects, 18 to 82 years old, largely reflected aspects of the U.S. population: 51% were women, 17% black, 10% Asian, 6% Latino.
Nonetheless, some experts suggested that a sample drawn from the world’s leading medical research facility might be considerably more health-conscious than most Americans. That might have led the researchers to underestimate the consequences of holidays.
“The findings are encouraging, but I would hesitate to extrapolate from them to the whole population,” said Dr. C. Wayne Callaway, a physician specializing in nutrition and obesity in Washington, D.C. Not included in the sample, he said, were important population subsets such as rural dwellers, the unemployed and women who work in the home.
Yanovski acknowledged limitations in the study sample, but added: “We think this is probably a pretty good guess as to what really happens to people over the holidays.”
