For millions of Americans, the holidays bring lots of stress as well as a heaping serving of extra calories that seems to go right to the gut. And science proves it. In a study published in the New England Journal of Medicine, researchers averaged the daily weights of 3,000 people in Germany, Japan and the U.S. for one year and saw that people were heaviest following every major holiday. For Americans, that means people weighed the most at the beginning of January (right after Christmas and the New Year), and researchers also saw a spike in weight gain right after Thanksgiving.

But it doesn’t have to be so. Here are some simple tips to follow to help you prevent weight gain over the holidays:

Take a hike — after dinner, that is

A 10-minute post-dinner walk can balance your blood sugar and help prevent unwanted weight gain. A 10-minute post-dinner walk can balance your blood sugar and help prevent unwanted weight gain. (Photo: Monkey Business Images/Shutterstock

It’s quite common for people this time of year to surrender to the shorter days, cold nights and hectic schedule of the holiday season. The urge to hibernate is very strong, especially for those who live in colder climates.

But even if you don’t have time to hit the gym, certainly there’s time for an after-meal walk. Involve the whole family if you can. Even taking just a 10-minute walk after a meal can do wonders for balancing blood-sugar levels, perhaps even more so than taking a walk before a meal.

Feasting on a holiday dinner and then succumbing to the magnetic powers of the couch and TV is a guarantee that you will gain unwanted weight. If you feel the powerful urge to retreat to the living room and watch some football after Thanksgiving meal, do so only after taking a walk.

This is perhaps the best way to ensure that you won’t pack on as much weight over the holidays. Make an after-meal walk part of your routine every day, especially after dinner. Got a ton of dishes to do? Leave them be, until you get back from your walk.

And don’t use the cold weather as an excuse. To quote the British adventurer Sir Ranulph Fiennes, “There is no such thing as bad weather, only inappropriate clothing.” So break out the fleece and start making after-dinner walks a nightly ritual, just like brushing your teeth.

Start an exercise routine before the holidays

Woman exercising at home Don't wait until after New Year's to start an exercise routine. If you're feeling motivated now, do it now. (Photo: Monkey Business Images/Shutterstock

If you are feeling motivated to begin an exercise regimen, don’t wait until after Jan. 1 to start. Use the next few weeks to boost your metabolism so you can eat some extra calories here and there over the holidays without feeling guilty and gaining weight.

In the beginning stages of an exercise program, the body’s physiology makes rapid changes. It’s only after several weeks or months after working out that “plateaus” occur and the body doesn’t respond to exercise as much.

If you have an aversion to going to the gym, begin an exercise routine today, not only by going for daily post-dinner walks but also when you are watching TV. Do some simple strength-training exercises during commercial breaks.

A typical 30-minute show on network TV contains nearly 10 minutes of commercials. If you do modified push-ups on your knees during the commercial breaks and begin this routine now, overindulging a little over the holidays will have a negligible impact on how much body fat you’ll gain.

Don’t stuff yourself

Turkey dinner with potatoes and vegetables Since starches like stuffing and potatoes can convert to sugar, fill your plate with proteins and vegetables instead. (Photo: Brent Hofacker/Shutterstock

Starchy foods like stuffing and mashed potatoes have a tendency to easily convert into sugars. Unless you’re going to go for a power walk or uphill hike after a holiday meal, cut down on the serving size of these starches so they don’t go to your waistline.

Limit the portion of starches to the size of your fist. If you don’t like the feeling of being bloated and overstuffed after a holiday meal, stop eating when you feel three-quarters full.

To ensure adequate fiber intake and vitamin content, make sure the one food you’re indulging in is vegetables (not potatoes). You can even put a little bit of butter on veggies like asparagus to feel satiated.

The bottom line to weight gain over the holidays is calories in versus calories out. If you consume more calories than you burn off, you will gain weight. That being said, however, eating a larger serving of turkey is the lesser of two evils. Protein doesn’t convert into sugars like potatoes, stuffing and cranberry sauce does.

So eat lots of veggies, enjoy your turkey and limit simple starches.

Editor's note: This story has been updated since it was originally published in November 2010.