With the holiday season upon us, that means parties, presents, good food and, sometimes, unwanted weight gain.

In lieu of setting goals to start losing pounds on Jan. 1, fitness trainers and nutritionists advise to be proactive about healthy habits now, to steer clear from packing on the pounds in the first place.

“Avoid the holiday bulge by being prepared and having a plan,” said Josh Holland, a Qinetic coach. “Most of us know by now that we can’t outwork a bad diet. The same applies for holiday binges.”

Here’s how to avoid the holiday bulge.

Don’t arrive on an empty stomach

Skipping meals in anticipation of high-calorie events seems logical, but it can have a negative outcome.

“Try not to go to a holiday party on an empty stomach — you’re more likely to overindulge,” said Lanae Rhodes, SLT’s director of training and development. “I always eat a smaller sensible meal of veggies and protein before the party.”

Then you can treat yourself — in moderation — at the party.

Make healthy swaps

For lighter holiday fare, ReViVer nutritionist Monica Reinagel suggested stuffed mushrooms instead of more caloric fare like bacon-wrapped appetizers. “Mushrooms make a nutritious and low calorie container for any type of savory filling,” she said. Shelled nuts are also good in place of a bowl of salted nuts because “having to shell the nuts as you go slows you down, so it’s harder to overdo,” she said. To satisfy a sugar fix, Mile High Run Club coach Hollis Lotharius recommended herbal teas. “They are calorie-free and hydrating — a true win-win,” she said.

Cut down on caloric drinks

When enjoying a drink or two, there are ways to avoid consuming unnecessary calories.

“Stay away from dark liquors, fruit juice or cream-filled cocktails,” said Lindsey Clayton, co-founder of Brave Body Project. “Stick to lighter liquors, a couple glasses of Champagne, a spritzer or a nice glass of red wine.”

Follow the buddy system

Go to the gym with friends or make working out a family affair this season, said Mahri Relin, owner of Body Conceptions.

“Play outside with the kids, go for a nice stroll through the park, get a group of friends together for a fun game of basketball or simply get in a good workout with a loved one,” he said. “I’m not a big believer of ‘calories in, calories out,’ but every little bit helps. If you’re consuming more, you’re going to have to move more.”