In terms of staying fit, it's the most blunderful time of the year. There's the nonstop revelry, the hectic pace, and all those delicious dishes that lead us into temptation and far, far away from our more healthful routines. We certainly don't want to be the Grinch who stole the Christmas cookies (have one!). But there's a fine line between indulgence and overindulgence (have one, not 21!).

The good news: The average person doesn't pack on that rumored 10 pounds over the holidays; studies show it's really one to three pounds. The bad news: If you gain a little each year and don't take it off, it adds up. The answer? Plan for situations and avoid the weight gain altogether. Here, top experts help navigate the stickiest holiday scenarios, so you can wake up feeling energized and guilt-free on New Year's Day.

Planes, Trains, and Automobiles
Heading home can be stressful -- from the clogged roads to flight delays. But your nervous noshing is preventable.

Carry-on Calories
"Pack a healthy snack," says weight-loss expert Stephen Gullo, Ph.D., author of "The Thin Commandments" ($25, Rodale). He suggests GG Scandinavian Bran Crispbread with Laughing Cow Light Cheese, an apple, or a Glenny's Brownie. "The brownies are great100 calories with 7 grams of fiber and some protein," he says. Or pick up a skim latte, low-fat yogurt, or Nature Valley granola bar, says New York City nutritionist Joy Bauer, R.D. "And if you're just bored, chew sugarless gum."

Think to Drink
To keep your spirits from flagging, drink water. Use the Hydration Calculator created by the Beverage Institute in Atlanta to find out how much you need based on age, weight, and activity level. When flying, drink two extra glasses. "Airplane travel is dehydrating: Air has about 60 percent humidity, but a plane cabin has only 15 to 20 percent," says Maxime Buyckx, M.D., director of health and nutrition at the Beverage Institute. If you're driving, don't deprive yourself of fluids to avoid bathroom breaks; drinking and walking will help prevent blood clots that can occur after hours of sitting.

Pub Night
It's the eve of Thanksgiving and all your old friends want to see if that cute bartender still works at the local hangout. The imbibing potential is massive.

Shift the Scene
Sitting in a bar eating nuts has little to do with celebrating Thanksgiving," Gullo says. Attempt to redirect friends to a less slothful pursuit, like ice skating, or skip pub grub for a potluck dinner at a friend's house.

Get a Good Seat
If everyone has her heart set on P.J. McDrunkard's, choose the bar stool farthest from the snacks. "When you're talking and drinking, it's easy to polish off 10 servings without noticing," Bauer says. And "studies show those are just bowls of bacteria," Gullo notes.

Double-Fist It (Sort Of)
"If you get a little buzzed, you will pretty much eat anything, says Bauer, who suggests alternating every alcoholic beverage with calorie-free club soda or seltzer.

Sip Smartly
Avoid highly caloric fruity or creamy cocktails and choose light beer (about 96 calories a glass) or wine (about 100). You'll cut even more calories if you go for a wine spritzer, New York City nutritionist Keri Glassman, R.D., points out. Vodka or a Scotch and soda is even better. "You'll drink much less, and avoid the bulge," says Gullo. And, finally, don't try to keep up with the boys. "Women metabolize alcohol at half the rate that men do," says Esther Blum, R.D., nutritionist and author of "Eat, Drink, and Be Gorgeous" ($23, Chronicle Books).

Thanksgiving Day
You don't have to choose between unbuttoning your pants after dinner or hurting Aunt Mabel's feelings by spurning her famous sweet-potato casserole.

Fake the Food Coma
"People feel pressured when a relative prods, 'Eat, eat,'" says Brian Wansink, Ph.D., author of "Mindless Eating: Why We Eat More Than We Think We Do" ($25, Bantam). "But new studies show the day after a dinner, the host doesn't remember how much people ate, just how many times people got seconds." Decide how much casserole you want and put less on your plate. The cook will be delighted when you politely go -- for just a tiny bit more.

Splurge Selectively
"Save your appetite for the meal," says Bauer. "Don't go whole hog on the pigs in blankets beforehand." At dinner, load up on all the skinless turkey and vegetables you want, and have a dollop each of two starches.

Make a Game Plan
"Always eat your protein first; it's the only nutrient that shuts off the brain's hunger mechanism," says Blum. "Have vegetables second, and starch third -- by the time you get to the carbs, you're less prone to overeat."

Bring It
Be polite and fitness-savvy; contribute a healthy side dish to the meal.

Slice Up Your Slice
Go ahead and eat some pie. Keep in mind you can shave off 100 calories a piece by forgoing the crust. "Pecan pie is 520 calories," says Bauer. "Without crust, it's only 420. Pumpkin is 320; without crust, my God, only 220!" And remember, you will live to eat pie again. As Blum says, "It's not your last supper; you don't have to eat like it is."

Office Orgies
You're back in the office. But now it's morphed into a bakery as clients send in treats and goodies by the truckload.

Stay the Course
Even though you're suddenly working in corporate Candyland, stick to your normal routine. "Have a good, fiber-rich breakfast and a good lunch with vegetables and protein, and you won't be as tempted," says Glassman.

Hold Out for the Holiday
"Ask yourself, is the treat really special? If it's something you could get any time -- like red and green M&M's -- skip it," says Glassman. If someone brings in something spectacular, have a small piece. But in general, put off partaking until the day before you leave for the holidays. That way, "you don't start a habit of eating sweets every day for three weeks," says Gullo.

Or send the Goodies Away
Recycle edible gifts," suggests Bauer. "Repack them and mail them off!" Or at least put them in the office kitchen, not on your desk: Wansink's studies show that if a candy bowl is more than 6 feet away from a person's desk, she will eat half as many pieces as when it's in front of her.

Trolling the Malls
Shopping: It's a tough job, but during the holidays, everybody's got to do it. Just make sure you don't end up starving and stumbling toward Cinnabon.

Drink Up and Pack Ammo
"A mall's fluorescent lights and concrete floors can be exhausting," warns Blum. "Make sure you keep your energy up." Bring water and a snack, and if you do have to stop, "sit and have a cup of tea and a low-fat yogurt," says Glassman. For lunch at the food court, "go ethnic," Blum says. "Have steamed chicken and vegetables at the Chinese food station, or sushi with miso soup." Or opt for a healthy meal over a Happy Meal: "McDonald's chicken Caesar salad with Paul Newman balsamic vinaigrette is a good fast-food option," says Gullo. Then use that energy to burn calories -- walk up the escalator and park far from your favorite flagship to sneak in some exercise.

Party Central
Between the family, the office, and the boozehound friends, you've got more parties to attend in the coming weeks than is humanly possible. But, in the name of holiday spirit, you'll try.

Dress for Success
Wear something "fitted and fabulous," says Bauer, "so you're reminded to be conscious of your clothes not popping." If you've got post-cocktail dinner plans and don't want to fill up on hors d'oeuvres, keep your hands occupied by "carrying a clutch and a beverage," suggests Gullo.

Eat Before you Meet
"Don't arrive famished, don't leave stuffed," instructs Glassman. Have a pre-party snack before an engagement. A mix of protein, carbs, and fats will keep you satisfied longest; try fruit and cheese, or a cup of low-fat cottage cheese. Once you arrive, "look for the healthier options, like crudites, shrimp, and chicken skewers," Glassman suggests. Sushi averages just 30 calories per piece. If you know your fattier favorites are going to be there, go ahead and enjoy them, just don't "save room" by starving all day. "That's a recipe for a binge," Blum warns.

Set the Scene
Always place snacks on "a serving piece," even if it's just a napkin. Then sit down. "If you're standing and grabbing mindlessly from platters, you overeat," Blum says. In a buffet situation, people consume two to two-and-a-half times as much as they would normally, says Gullo. To avoid this, reach for a salad plate, not a dinner plate. "We eat more when we're given a bigger container. Period," says Wansink.

Pour a Tall One
Wansink's studies also show that people overpour liquid when using wide glasses. If the host's entire barware collection is out, pick a tall, skinny champagne flute instead of a big Barolo wine glass and you'll drink less. Also, "it's very easy to forget what we've had," Wansink says. To keep track, always pour a new drink (tactfully decline refreshers) and save the cocktail napkin from each one so there's no denying how many beverages you've imbibed.

Sleep It Off
If you're out a lot, make sure you get enough shut-eye. "The average person needs eight or nine hours, more in winter because our bodies are programmed to sleep when it's dark," Blum says. "People who don't sleep enough are more prone to weight gain because of hormone disruptions."

December 21
Festivity fatigue sets in. You wake up hungover, bloated, and wanting to curl up with a log of Nestle Toll House cookie dough until mid-January.

Go Back to Bed
Sleeping enables your body to digest alcohol. "You burn off about two-thirds of a drink per hour," Blum says. "This rate may slow while you're sleeping, so give yourself extra time to rest after a night out."

Cut Out the Hair of the Dog
Instead of more booze at brunch, down tomato juice -- "the fructose will help your body metabolize alcohol more quickly," Blum explains. Use it to wash down a magnesium supplement, such as GNC Magnesium 500 ($7, drugstore.com), to help remedy the depletion that occurs when you drink alcohol

Chill Out
Hit the gym, watch a "Hills" marathon, meditate -- whatever it takes. "High stress levels lead to weight gain," says Blum. "Just 10 minutes of yoga a day can keep your levels normal." Exercise also helps. But you should work out to maintain fitness and sanity, not for a full-body makeover. "Try not to pressure yourself to lose weight now or you'll feel deprived," Blum advises. "It's more important to keep all systems normal."

Get Back on the Horse
"If you eat a lot one day, it's not a big deal as long as the next day you have a healthy breakfast, go the gym, get back to your routine," says Glassman. So don't pig out, give up, and table fitness until 2008. "The more you say 'tomorrow,' the more you'll weigh tomorrow," says Gullo.