Common eating myths, such as "unavoidable" holiday weight gain, may deter you from enjoying your favorite foods this time of year. Don't let them. Here's good advice to help you maintain your healthful eating habits—and your waistline.

Myth #1: Most people put on five to seven pounds during the holidays.
Reality: The average weight gain during the six-week span from Thanksgiving to New Year's is just under one pound, according to a yearlong study of nearly 200 people published in The New England Journal of Medicine. Even though enjoying delicious holiday dishes might not increase your waistline by as much as you'd expect, calorie consciousness is still important.

Eat-smart strategy: Many common holiday foods—sweet potatoes, dried fruit, and turkey, to name a few—are nutritious options when enjoyed in moderation. Sneak in a little extra physical activity every day to burn off additional calories and benefit from the stress-reducing effects of exercise.

Myth #2: Eat a lot of turkey, and you'll be snoozing shortly.
Reality: Studies have linked L-tryptophan—an essential amino acid found in cooked turkey—to a feeling of sleepiness, but it's unlikely that eating turkey during the holidays will have a sedating effect, says Milton Stokes, R.D., a spokesperson for the American Dietetic Association. In order for L-tryptophan to cause sleepiness, research has shown that it needs to be eaten alone, on an empty stomach. "Protein and other nutrients found in turkey interfere with the absorption of this amino acid, inhibiting the sleep-inducing effect," Stokes says.

The real reason a nap is so appealing after any big meal is the large amount of energy required to digest it, Stokes says. During the process, blood is diverted away from the nervous system and to the digestive system—where it's needed to help break down food and absorb nutrients. "It's no wonder people are left feeling less energetic, fatigued, and even foggy-headed," Stokes says. Your body signals you to rest because it has a lot of work to do.

Eat-smart strategy: One way to avoid a post-meal energy drain is to approach a big dinner with an appetite that's in check. Avoid eating smaller-than-normal portions for breakfast and lunch, which may leave you feeling ravenous at dinner and prompt you to eat more than normal, Stokes says.

Myth #3: Great cooks and festive parties place our willpower at risk.
Reality: Research indicates that it's not the parties that prompt us to eat, but being around friends and family that may lead to diet missteps. In a study conducted at Pennsylvania State University in University Park, researchers found that dining in a group causes the average person to eat 44 percent more calories than they normally would eating alone. "When you're socializing, it's natural to lose track of what and how much you're eating," says Barbara Rolls, Ph.D., professor of nutritional sciences at Pennsylvania State University. "Since the number of distractions will most likely be greater, a holiday party can increase the tendency to overeat even more than just going out to dinner with friends."

Eat-smart strategy: Mindful eating is key to maintaining your equilibrium during social situations. Since you don't want to offend by skipping your host's offerings, try taking a smaller serving. Make a conscious effort to balance your plate with plenty of fruits and veggies, and a healthy portion—about three to four ounces—of protein, Rolls says. Also, take a second to look at every bite before you eat it. This psychological connection will help you keep a mental checklist of how much you're consuming.