The Festive Season, Short-Term Overfeeding & Your Weight


The festive season is upon us, which for most, means a never-ending supply of delicious tasty Calorie-dense food.

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For some people, like those who are trying to lose fat or those that are trying to maintain weight or even those people who are just mindful of their food intake, the festive season and the effect it could have on their waistline may cause some anxiety.

But, fear not that pav and choc-ripple cake this festive season.

A study published in 1985, looked at 5 healthy men (22-27yo). All were non-diabetic, non-smokers. These 5 men ate 60% more Calories than the amount they would require to maintain their weight. They did this for 9 days.

They increased their food intake for 9 days by an average of 1,914 Calories each day to see how much weight they would gain.

They went from eating about 3,279 Calories to eating ~5,193 Calories. These Calorie intakes were a little different between subjects as they were specific for the individual subjects.

This diet was fairly low in protein with protein making up just 15% of total calorie intake. This is important as the effects of overfeeding on a high protein vs low protein diet are different.

A low protein diet is less favourable for weight maintenance/weight loss and probably more closely resembles the typical diet over the festive season (less protein, foods high in fat and carbohydrate such as dessert type food).


The study showed that on average the subjects gained 3.2kg of weight in 9 days. BUT, only 56% (1.8kg) of this was actual body fat.

The study also showed thatoverfeeding caused an initial rapid weight gain that became slower over the 9 days (see fig below).


The remaining 44% (1.5kg) of weight gain was most likely due to increased body water content. Organ mass or non-muscle lean tissue may also have contributed.


Other studies show similar results with fat mass gain making up 60-70% of total weight gained. Some of these studies are longer in duration though so may not be as applicable to the festive season.

If you are interested in reading a complete summary of the literature including overfeeding on carbohydrates vs fats or overfeeding on high vs low protein, follow this link.


If you are looking to make calorie conscious decisions with your food selection over this period consider filling your plate first with lean protein sources (meat, fish etc) and plants (vegetables, fruit & salads). Consider low calorie alcohol options or sugar free sodas as mixers. Swap full fat cream for low fat cream. Swap high calorie dressings for low calorie dressings. Use low sugar jelly. There are plenty of easy swaps like these to help reduce calorie intake.


With the research above in mind, you can overeat between Christmas and New Years Day and potentially not gain much fat. This of course depends on the exact amount of overeating and total Calories you consume in this period. Obviously, if you decide Christmas Day is a great chance for that 10,000 Calorie challenge your fat gain may be larger.

While you may gain weight over the next few days, remember that not all of it is fat.

So, relax, enjoy the time spent with family & friends. Give yourself permission to eat anything. Enjoy good food without feeling guilty, just don’t eat like a complete moron.

Once the festive season is over go back to the way of eating that had you on track for your goals. No biggy.

In 10 years time that Christmas that you ate all the food you enjoy won’t be a factor.

Christmas is no time for Tupperware, chicken and broccoli.

If you need help achieving a weight goal, contact me.


Daniel Reeves

Physiotherapist, MNU Certified Nutritionist

The Strength Den, Burnie Tasmania

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