Holiday weight gain is smaller than you think, and that's the problem

Most people gain far less over the festive season than they fear. The catch is that the small amount rarely comes off, and one simple habit stopped it in trials.

Ask anyone in late January how much weight they put on over the festive season and you will usually hear "two, maybe three kilos". When researchers actually put people on a scale, the average was closer to a third of a kilo ¹.

That sounds like good news, and partly it is. The catch is what happens to that small number afterwards.

How much weight do people really gain over the holidays?

The best-known study on this question weighed 195 adults, aged 19 to 82, four times between late September and early March ¹. To stop people changing their habits for the scale, the researchers also measured blood pressure, pulse and stress, and most participants never worked out that weight was the real point ¹.

Over the holiday stretch from mid-November to early or mid-January, the average gain was 0.37 kg ¹. Fewer than 10 per cent of people gained 2.3 kg or more, the figure popular articles of the time liked to quote ¹. The participants themselves guessed they had gained about 1.57 kg, roughly four times the measured amount ¹.

Later work broadly agrees. A review of the research found that adults consistently gained somewhere between 0.4 and 0.9 kg over the year-end holiday period ². So not the five-kilo horror story. But not zero, either.

Why a small festive weight gain still matters

Here is the twist. In that first study, the weight gained over the holidays did not come off in the following months ¹. By February or March, people were still an average of 0.48 kg above their September weight ¹. Among the 165 who came back to be weighed again the next autumn, the total gain for the whole year was 0.62 kg, and about half of it, 0.32 kg, had arrived during those six or so festive weeks ¹.

Most adults put on weight slowly, a fraction of a kilo a year, and rarely notice it happening ¹. Ten years of "only half a kilo" is five kilos. The researchers concluded that this short season probably contributes a good share of the weight people gain through adulthood ¹.

The festive season rarely adds weight all at once. It leaves a small deposit every year, and nobody comes back to collect it.

Is it the parties and the sweets?

You might expect the number of celebrations to predict the gain. It did not. In the same study, how many parties people went to was not linked to how much weight they put on ¹. Only two things were: changes in physical activity and changes in hunger ¹. People who said they had become much less active, or much hungrier, gained the most, while those who reported being much more active tended to lose weight ¹.

These are associations from one study, not proof. But they match what this time of year looks like in India. Diwali boxes of mithai, wedding functions where dinner opens at ten at night, December office parties, then the New Year week off. The morning walk vanishes because the evening ran late. The gym gets pushed to "after the shaadi". Meals become bigger, later and more frequent. One heavy evening is rarely the problem. Six or eight weeks of slightly less movement and slightly more food usually is.

Does weighing yourself every day stop holiday weight gain?

This is where the research gets genuinely useful, because a handful of trials have tested ways to stop the creep.

In a US trial, 111 adults were randomly split into two groups before Thanksgiving ³. One group weighed themselves every day on Wi-Fi scales, saw the readings as a graph, and were told only to try not to go above their starting weight ³. Nobody gave them a diet ⁵. Over the holidays their weight held steady, while the comparison group gained an average of 2.65 kg ³. Fourteen weeks later the comparison group had lost some of that but were still 1.51 kg heavier than when they began ³.

A UK trial of 272 adults, called the Winter Weight Watch Study, tried a similarly light touch ⁴. Participants were asked to weigh themselves at least twice a week, ideally daily, and write the number down. They also got ten weight management tips and a list showing how much exercise popular festive foods were worth: a mince pie took 21 minutes of running to burn off, a small glass of mulled wine 33 minutes of walking ⁴. The comparison group gained some weight over Christmas. The intervention group did not, and finished about 0.49 kg lighter on average ⁴.

A 2024 systematic review pooled five adult studies and found that the interventions reduced weight gain by about 1 kg compared with control groups, and by about 1.45 kg in the studies run over the December holidays ⁵. The authors rated the overall certainty of the evidence as very low, because the trials were few, small and varied, and nearly all came from the US and UK ⁵. Still, the most promising approach they identified was plain: frequent self-weighing combined with simple eating advice ⁵.

Why would a scale work when willpower so often does not? The likeliest reason is early feedback. You notice the half kilo while it is still half a kilo, not in February when it has quietly become two.

One honest caveat. Daily weighing is not for everyone. If the number on the scale tends to ruin your mood or pull you towards skipping meals, a weekly check or a favourite pair of trousers is a perfectly good gauge instead.

How to avoid weight gain in the festive and wedding season

None of this means saying no to the laddoos or sitting out the sangeet. The aim is to stop a few good weeks from turning into a permanent kilo. A few things worth starting this week:

• Weigh in the morning, the same way each time. After the loo, before breakfast, same scale, ideally daily and at least twice a week ⁴. Watch the weekly trend rather than any single reading, because day to day numbers bounce around.
• Set a ceiling instead of a diet. The UK trial asked people to gain no more than 0.5 kg over the season ⁵. If your weekly trend crosses that line, tighten up for a few days, then relax.
• Protect your movement before anything else. Activity was one of the two factors most closely tied to holiday gain ¹. Decide on a minimum that survives late nights, such as a 20-minute walk or a short strength routine at home, and keep it on the busiest days. A short stroll after a heavy dinner helps too, for reasons we covered in our piece on walking after meals.
• Do not arrive at the buffet starving. Hunger was the other factor linked with gain ¹. A proper lunch and a protein-rich snack before a late function make it much easier to eat one good plate instead of three hurried ones.
• Check the exercise cost once. Look up the calories in your two favourite festive sweets and work out how long a walk would burn each off. You will not want to do that maths at every party, and you do not need to. Once is usually enough to reset your sense of a sensible portion.
• Plan the January reset now. Put a normal training week in your calendar for the first week after the last wedding or holiday, so the routine has a fixed restart date instead of a vague "soon".

If you have diabetes, a heart condition, are pregnant, take regular medication, or have a history of disordered eating, speak to your doctor before changing how you eat or starting daily weigh-ins.

The kaju katli was never the real problem. The real risk is the half kilo that stays behind after the guests have gone home.

General information for healthy adults, not medical advice. Speak to a doctor before changing your training or diet if you have a health condition, are pregnant or take regular medication.