It's that time of the year when healthy eating and moderation take a back seat to Christmas cheer and all the goodies that entails.

As your social life expands over the coming weeks, how do you stop your waistline from doing the same?

Dietitans Association of Australia spokesperson Milena Katz said strategies could be adopted to manage both food and alcohol intake during party season.

As a starting point, decide what the biggest meal of the day will be and change your eating habits accordingly.

"If you are going out to a big three course hot lunch then have what you would normally have for lunch for dinner, like a salad or sandwich," she said.

At a cocktail function with trays and trays of delicious finger food whizzing around, avoid all things deep fried in favour of fresh items such as sushi, rice paper rolls and sashimi.

"If you don't stand near the food it won't come to you so much," she said.

While it is tempting to eat before an event so you'll feel full and not indulge, Katz said this just didn't work.

However to stop you from pouncing on the first tray of mini-quiches you see, take the edge off your hunger by having a small snack a few hours before the event.

"It is really hard to eat before you go because when you're there you still want everything," she said

"It is better not to go in starving, perhaps have afternoon tea, have a yoghurt or something a few hours before a function."

Applying a similar philosophy to buffets, always head to the salad first and then go back for some protein. For a set lunch, Katz warns to "watch the bread", which is often served first when guests are ravenous.

"If you're going to a buffet go to the vegetable based salads not the creamy based salad," she said. "It will start to fill you up with fibre."

"Pick (fresh) fruit based desserts. If there's a fruit flan or fruit salad, choose those over chocolate cake or brownies."

And don't be fooled by the dried fruit content of Christmas fare like pudding.

"Fruit cake is quite dense, it is energy packed, it would be the same as some chocolate cakes in terms of calories," she said.

Alcohol often fails to register as being a source of calories and can often be where people come undone.

"It adds on extra energy that people don't realise because it's fluid," Katz said. "They don't feel particularly full from it so they don't think 'oh, I've just had a meal'."

Katz said spirits with a diet soft drink or soda water were a lower calorie option and rotating an alcoholic beverage with water was good for both the waist line and the head the next day.

"That (spirits) has less calories and champagne is better than wine as it has less carbohydrates and less energy overall," she said

Ramping up exercise can also help to negate all the extra calories being consumed during Christmas celebrations. As a blanket rule Katz recommends doing an extra hour of exercise for every function attended.

However, it was okay for dieters to lower their weight loss expectations over the festive season.

"It is most likely that the ones who are trying to lose weight will maintain their weight over Christmas," Katz said.

"If they keep trying to lose weight they might end up skipping meals and that doesn't help weight loss.

"Think about the family and friends they haven't seen in a long time. Don't focus on the food as it can be upsetting."