This time of year, people watching their weight while facing down holiday happy hours and open houses can be particularly susceptible to scaremongering by the fat police. You know the type: the guests who spoil the party by rattling off the calorie counts in the gingerbread men and staring you down as you reach for the eggnog.

Unfortunately for the rest of us, many of those spoilsports have found work in the country’s public-health industry, earning their living by professionally shaming those who indulge in the end-of-year parties. Groups like the Center for Science in the Public Interest (CSPI) have made careers out of being food Grinches. And now there’s plenty of merriment around to steal.

Last Christmas, CSPI accused several beer companies of using Santa to promote binge drinking – in reality, pub crawls hosted by St. Nick impersonators to aid charities.

But there’s no reason to believe that Christmas treats will leave you as rotund as Santa. The key to maintaining a healthy weight is moderation, and a celebration that happens once a year is the definition of moderation. One salad never made anyone thin; one hot toddy never made anyone fat.

And it’s easier than ever to keep a handle on your calories-in vs. calories-out. The Associated Press compared the 1956 edition of the Better Homes and Gardens cookbook with the 2006 version and found that holiday recipes have actually gotten healthier. More dishes called for lower-calorie ingredients, and portion sizes are trending smaller as well.

As far as the exercise side of the weight equation goes, study after study underscores the importance of all kinds of physical activity in weight control. For those who welcome the first snowfall, winter sports abound: skiing, sledding, ice skating and snowshoeing are all fun calorie burners. And health clubs typically offer special rates for new members around the time that everyone is coming up with New Years resolutions.

So go ahead and savor the Hanukkah latkes and Christmas cookies. Christmas comes but once a year, as the carol goes. Don’t listen to anyone who tells you not to enjoy it.