Australians can take some simple steps to avoid gaining weight and wasting food this festive season, says AMA Vice President, Dr Tony Bartone.

Forget the turkey, ham and prawns, the nation's peak medical body says a healthy serve of fresh salad is more appropriate to keep the kilos off on Christmas Day.

The Australian Medical Association has issued a gentle reminder that over-indulgence in food, alcohol and confectionary over the Christmas/New Year holidays will lead to adding on an extra kilo or two.

Australians can consume three times as many kilojoules as they need just on Christmas Day, the medical body warned on Thursday.

"Some Australians will consume more than 25,000 kilojoules - or 6000 calories - on the day, which is three times the amount of energy needed by a moderately active adult," AMA Vice President, Dr Tony Bartone said in a statement.

However, there are many practical ways to avoid weight-gain over the festive season, Dr Bartone says.

"First, consider how much food you actually need to purchase and prepare. When entertaining, there can be a tendency to over-cater, and much of this food is thrown away," he advised.

"A healthy serve of fresh salad, especially at the start of lunch or dinner, is a simple suggestion which allows people to fill up on fresh vegetables."

Other healthy tips from the AMA include: drinking plently of water and watching the alcohol intake, watch portion sizes, slow down and enjoy the food, and go for a walk or bike ride after eating.

"These steps can help keep your weight in check, and make your New Year resolutions easier to keep," Dr Bartone said.