Start the clip in the player to take part in the Christmas dinner tips.
Food production accounts for a third of all greenhouse gas emissions in the world.
Throwing away a lot of food is a double fault in terms of environmental impact.
Food at the centre of the city at Christmas – does it have to be done in abundance?
Associate Professor Helén Williams notes that social interaction during Christmas and New Year is important to many, and that food often takes centre stage. But a central question to ask is whether it must be done in abundance, she says.
"Perhaps, in a time of high food prices and a world situation that indicates awareness, we can eat what we buy home," says Helén Williams.
In the video above, Williams gives tips on how to avoid getting a lot of leftovers, but also how to think about taking care of and refining the Christmas food that is still left over.