Do you seem to put on a few pounds every holiday season? Not surprisingly, this happens to many people during the winter doldrums. Some of it can be attributed to the less-than-healthy holiday options served at most parties, but the crux of the problem is based less on candy and more on evolution and science.

Our very distant ancestors (I'm talking Neanderthal distant) were oftentimes faced with a dearth of food options during the winter season. In response, the human body slowed down the metabolism, thus helping to ensure survival until the warmer and more plentiful months returned. For some reason, we have evolved well past being impressed by fire, but for some reason this winter survival mode persists. But how does it actually happen?

Well, science may have at least found somewhat of an answer to that question. According to a recent study from the National Institute of Mental Health, some people may not process leptin (a hormone that regulates cravings and hunger) as efficiently during the winter. Researchers aren't exactly sure why this occurs, but they do agree that a reduction in leptin production can lead to increased appetite and, in turn, weight gain.

One way to increase leptin production is to make sure that you are getting enough sleep, as it is during times of rest that this hormone is created. Also, leptin deficiency has been linked to low zinc intake. Since zinc has also been shown to reduce the severity of a cold if taken at the earliest stages, you may want to have some of this mineral stocked up already.