Here are some of my favorite ideas to stay fit and healthy during the holidays:
Plan what you eat
I think about the events in my day ahead of time and plan what I will eat. For example, if I will be attending a party that evening that features Mexican food, I think ahead and choose to eat just one tamale, choose black beans over refried beans, and choose loads of pico de gallo and a dollop of guacamole. Then when I arrive at the party, I feel confident because I have a plan that won't derail my diet.
If I am looking forward to a fabulous steak dinner with all the trimmings, then my lunch will be heavy on vegetables & fruit with a vegetarian protein. Maybe a large salad with hummus on a rice cake and an apple. That way my calories and fats are more consistent for the day.
Choose to do one active event each day during December. You will be able to maintain your regular workout at the gym most days but if not, make a plan. Can't make the morning class? Try a new class in the evening. Your aunt & uncle are visiting? Take a walk around the neighborhood to see the yard decorations. Kids are home from school? Hike up at Stough Canyon and visit the Nature Center. You need to be at the school for another holiday performance? Allow a little extra time and walk. You might actually save time since your don't have to hunt for parking. Remember to park at the farthest point in the mall parking lot and you will get a little extra mileage for the day.
By making a plan, you will empower yourself to make healthy choices during the holidays.