Roger Cone, a professor at Vanderbilt University says, on average, weight gain from Thanksgiving through New Year is closer to three-quarters of a pound to 1 pound through the holiday period.
However, Cone says, while adding a pound is not drastic, what typically happens with obesity is people gain weight slowly and keep it on over a long period.
"It is not just overeating at holidays. We are chronically overeating and under-exercising in this country," Cone says in a statement. "And what happens then is your weight gradually creeps up."
If people become obese it is because there is a minor difference between what they are consuming and burning, Cone says.
"So the trick is to try to match your energy expenditure with your energy intake, to try to control your diet overall, and keep it healthy and to try to up your activity until the two are in balance," Cone says.