Scientists at Thinktank, a new museum of science and discovery in Birmingham, Britain, have calculated that the average person burns off 26 calories in a one-minute kiss under the mistletoe.

"Kissing can have all sorts of physiological effects. Your pulse rate goes up, your blood pressure may rise, the pupils in your eyes get bigger and you breathe more deeply," said Dr. George Foster, a scientific advisor at the center.

"The pleasure centers in your brain become active as neurotransmitters are secreted and your thought processes may become different. Many of the effects are very like those when you are excited or surprised and I guess a good kiss may be the reason for both," he added.

And while on the subject of kissing, here's some lip-smacking trivia: The average person spends two weeks of their life performing philematology, the scientific name for kissing.

And the world's longest non-stop kiss ever was 29 hours by a couple in New York on March 24, 1998. According to Dr. Foster's calculations that would amount to some serious calorie burning.