Christmas is described as several consecutive weeks during which habits change, meaning the overall effect becomes greater than most people expect.
According to Foodsense Consumer Reports on Health, the average adult gains around two kilograms during the Christmas period, and the weight rarely disappears again.
This makes Christmas relevant from a broader public health perspective.
Small changes over time
The decisive factor is not one Christmas Eve. It is repetition.
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Workplace Christmas lunches, weekends without fixed routines, and numerous social engagements often mean more food, more alcohol, and less physical activity.
The Healthy Eating Hub points out that many people already have a high energy intake throughout the rest of the year.
When December is added on top, a cumulative surplus emerges, which the body stores. This happens gradually and often without being noticed.
The role of alcohol
Alcohol plays a particular role during the Christmas period.
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According to the Australian Government Department of Health, consuming more than four standard drinks on a single occasion is considered excessive.
This threshold is based on the strain placed on the body, especially the liver and the heart.
When this type of intake is repeated several times over a few weeks, the overall health risk increases, even if each individual evening may feel moderate.
The long-term effect
The explanation for why the weight stays on is linked to habits. Repetition makes behavior feel normal, even after Christmas.
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At the same time, activity levels often decline during the winter months due to darkness and cold.
The point, therefore, is not to avoid Christmas, but to understand that it is a recurring period with significance for the entire year.
Sources: The Heart Research Institute, The Healthy Eating Hub, Foodsense Consumer Reports on Health, and Australian Government Department of Health.
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