‘Tis the season to celebrate.

As we gather with friends and family, we snack all day on tasty appetizers, enjoy festive cocktails, include wine with dinner, and cook multicourse meals that include grandma’s favorite sugar-laden pies.

Then there’s the company party, the holiday girls’ night out, a New Year’s Day football game.

Let’s face it: ‘Tis the season to pig out.

The average American gains between 1 and 10 pounds between Thanksgiving and Christmas, depending on which study you want to believe.

Not that big a deal, right?

Actually, it is.

Considering that 38 percent of people in the United States are obese and 33 percent are overweight, and that we gain and keep an average of between one and two pounds every year, even one additional pound spells trouble in the long run.

What happens to your body?

One of your stomach’s big jobs is to secrete hydrochloric acid to begin the digestive process and kill bacteria as food moves through your digestive system.

The more you eat, the more acid you produce. And some of it makes its way up the esophagus, resulting in heartburn.

Big meals slow your digestion and food spends more time being processed. That causes the gassy, bloated feeling you often have after a big meal.

As your body calls “all hands on deck!” to digest the food load you’ve just consumed, it sends more blood to your gastrointestinal tract.

That means less blood is available to transport oxygen and nutrients to other parts of your body, leaving you sluggish and lightheaded.

Pigging out also causes your blood sugar to spike, especially if you’re consuming a lot of carbohydrates or sugar.

When blood sugar rises above normal levels, you release excess amounts of the hormone insulin and you get an energy spike.

The initial boost may spurt you onto a quick kitchen cleanup, but it’s usually followed by a crash.

Your body thinks you don’t need all that energy as fuel and it starts storing more of it as fat.

Add alcohol to this caloric overindulgence and you’ll probably toss and turn all night.

When you wake up in the morning, you’re starving because your pancreas has been working overtime to process all that food and drink.

You might also have a headache, difficulty concentrating, brain fog, or fatigue.

So even if you only gain a pound or two from holiday indulging — who needs that extra pound, or a food and drink hangover?

What can you do to avoid holiday weight?

“Just say no” is a common strategy.

However, Susan Weiner, MS, RDN, CDE, CDN, a registered dietitian, nutritionist, diabetes educator, and author, said that simply limiting or restricting what we eat doesn’t work because it makes us feel deprived, anxious, and martyr-ish.

“Be in the present and practice mindfulness,” Weiner told Healthcare Website. “Eat what you enjoy and savor the flavor of the moment.”

Mindfulness, she explained, can extend past the sensation of taste.

“Pay attention to what you put on your plate. Be aware of the high number of calories in alcohol. Sit down to eat, try not to graze while you are preparing food,” she added. “If you do overeat, don’t beat yourself up. Just take a deep breath, move on, and plan to make better choices moving forward.”

Here’s some other advice:

Exercise. Try to keep up your normal routine as much as possible. When you head downtown or to the mall to shop, park your car away from the stores. Wear comfortable shoes and walk briskly from shop to shop. After a big meal, go for a neighborhood stroll. Get the family involved with a game of touch football or sledding. Play active indoor games like ping pong, charades, or Bakari.

Rethink favorite foods. Eating Well magazine has recipes that slim down beloved standards like mashed potatoes, buffalo wings, and holiday drinks. In “Skinny Chicks Eat Real Food,” celebrity chef Christine Avanti offers dozens of options for healthy holiday feasting.

Forget fasting. Many of us believe if we “conserve” calories all day, we can overindulge in the holiday meal. Trouble is, that causes your metabolism to think you’re going into starvation mode so it holds on to as many calories as possible. A better plan is a low-fat, protein-rich breakfast, a light lunch, and a moderate holiday meal.

Listen to your body. Start by taking small portions and mindfully enjoying what’s on your plate. Skip seconds and leave room for a reasonably-sized piece of pie.

Think before you drink. One beer can pack 175 calories, a glass of wine weighs in at 160, and that perennial favorite egg nog tops out at 223. You don’t have to be a teetotaler during the holidays. Just sip lightly, slowly, and choose lower calorie drinks.

Sleep. Getting enough rest is key to overall health, wellness, and your ability to maintain a healthy weight. Slow down, breathe deep, and stop stressing over every gift, card, and party.