But don't get too happy: researchers warned it is also likely you will keep that pound with you for the coming year.
"The idea that everyone gains five to seven pounds during the holidays is humbug," said Patrick O'Neil, director of the Weight Management Center at the Medical University of South Carolina.
O'Neil and Jack Yanovski, the head of the Unit on Growth and Obesity at the National Institutes of Health, discussed a study of holiday weight gain during the annual meeting of the North American Association for the Study of Obesity.
O'Neil said the common wisdom is people gain about five pounds over the holidays but it was unclear just where that number came from.
So the researchers set out to see just how much weight people actually gain from Thanksgiving through the first week in January.
Those in the sample of 200 adult men and women from the Bethesda, Md., area were weighed during the study, but other vital signs also were taken so participants would not know the research was about weight gain.
The results showed participants gained just under one pound during the holidays, with men and women gaining about the same.
Yanovski said the average person seems to gain about a pound a year so there may be indications that weight gain comes mostly from holiday eating. He said participants were not asked what type of foods they ate.
Starting the study, the researchers felt a five-pound weight gain would not prove accurate.
To gain that much weight, O'Neil said, you would have to consume an extra 3,500 calories a week. That's the equivalent of drinking an extra case of beer each week, in addition to your regular diet.
The best way to approach the holidays, he said, is to "eat, drink and be wary."
Also Wednesday, the 1,200 doctors, researchers and dietitians attending the conference heard that health-care costs are higher for people who are obese.
One study found annual medical care costs for obese people are 36 percent higher than for those with normal weight. Another found that participating in a weight management program, for those who need it, lowered health care costs $1,648 a year.
"The costs of obesity are alarming and will continue to grow as the epidemic grows," said Dr. Charles Billington, the association's vice president. "Obesity is not only responsible for causing serious health problems, but also a considerable financial burden on patients and society."