Every December, the same anxiety surfaces. "I'm going to gain so much weight over Christmas." The fear is almost as traditional as the turkey itself.
But how much weight do people actually gain? And is it really as catastrophic as we imagine? The research tells a more reassuring story than the diet industry would have you believe.
The Myth: 5-7 Pounds of Christmas Weight
You've probably heard the claim that people gain 5-7 pounds (2-3kg) over Christmas. It's repeated endlessly in magazines, fitness articles, and diet company marketing. There's just one problem: it's not true.
Where the Myth Comes From
The "5-7 pound" figure appears to have originated from diet industry marketing in the 1990s. It was repeated so often it became accepted fact. But when researchers actually measured holiday weight gain, they found something quite different.
What the Research Actually Shows
The landmark study on holiday weight gain was published in the New England Journal of Medicine in 2000. Researchers at the National Institutes of Health tracked 195 adults through the holiday period and found the average weight gain was just 0.37kg - less than a pound.
UK-Specific Research
A 2020 UK study found slightly higher gains - around 1.2kg on average. Interestingly, UK participants gained more than those in Portugal and Denmark, suggesting cultural differences in how we approach festive food.
A 2016 study across the US, Germany, and Japan found weight increases of 0.4-0.6% of body weight - that's about 300-500g for most people.
| Study | Average Gain | Country |
|---|---|---|
| Yanovski et al. (NEJM 2000) | 0.37kg | USA |
| Helander et al. (NEJM 2016) | 0.4-0.6% | USA, Germany, Japan |
| UK Holiday Study (2020) | ~1.2kg | UK |
Why This Matters
The gap between feared weight gain (5-7 pounds) and actual weight gain (less than 2 pounds) matters because it affects how we approach the holidays.
When we expect catastrophic weight gain, we might:
- Restrict severely before Christmas, leading to binge eating when we finally "allow" ourselves food
- Adopt an "all or nothing" mentality - "I've already ruined it, might as well eat everything"
- Plan extreme January diets that are unsustainable and often counterproductive
- Experience unnecessary guilt and anxiety that spoils the celebration
When we understand that a typical Christmas results in less than 2kg of weight gain - much of which is temporary water retention and food volume - we can approach the season with far less stress.
The Real Concern
The NIH research found something important: the small weight gained over Christmas often isn't lost in the following months. It's not the amount that matters - it's the accumulation. A small annual gain, year after year, adds up. This is why sustainable habits matter more than dramatic post-Christmas diets.
What Actually Causes Holiday Weight Gain
It's probably not what you think. Christmas dinner itself - even with all the trimmings - is a single meal. The real culprits are:
The Extended Grazing Period
Christmas isn't one day of eating; it's often 2-3 weeks of constant availability of treats. The tin of Quality Street on the coffee table. Cheese and crackers before dinner. Mince pies with every cup of tea. This continuous low-level overconsumption adds up far more than the big meals.
Increased Alcohol
Festive drinks contribute significant calories while also lowering inhibitions around food and disrupting sleep (which affects appetite hormones).
Disrupted Routines
Time off work, late nights, irregular meals, and less movement all contribute. The lack of structure removes the automatic healthy habits many people maintain during normal weeks.
The "Start Monday" Mentality
Knowing you plan to diet in January can paradoxically increase December eating. "I'll deal with it later" becomes permission to overeat now.
Why January Crash Diets Make It Worse
Here's the uncomfortable truth: the January diet is often more damaging than the Christmas eating.
Research on New Year's resolutions shows that approximately 80% of people abandon their diet by the second week of February. Strava's analysis of 800 million activities identified January 19th as "Quitter's Day" - the day most resolutions are abandoned.
Crash diets fail because:
- They're too restrictive - Dramatic calorie cuts increase hunger hormones and decrease willpower
- They're temporary by design - A "January diet" implies you'll stop in February. Then what?
- They create a feast-famine cycle - Restriction followed by resumption of normal eating (or rebound overeating)
- They don't address habits - The behaviours that led to weight gain are still there when the diet ends
The weight lost on crash diets is typically regained within months, often with additional pounds. This yo-yo pattern is arguably worse for metabolic health than maintaining a stable (if slightly higher) weight.
A Better Approach
Instead of dramatic restriction in January, focus on simply returning to your normal eating patterns. No detox, no cleanse, no extreme measures. Just regular meals, adequate protein, vegetables, and resuming whatever movement you normally do. The small Christmas gain will resolve itself within a few weeks.
Evidence-Based Strategies That Actually Work
A UK intervention study found that simple awareness strategies prevented holiday weight gain entirely. Participants who received basic guidance, weighed themselves regularly, and understood how much activity was needed to offset treats maintained their weight through Christmas - no restriction required.
During the Holiday Period
- Keep some structure - Regular mealtimes prevent constant grazing
- Maintain protein intake - Turkey, ham, and salmon are traditional for good reason. Protein keeps you satisfied
- Move daily - Not as punishment, but for energy and mood. A family walk is festive
- Be selective with treats - Enjoy what you genuinely love; skip what's just there
- Watch the drinks - Alternate alcoholic drinks with water
After Christmas
- Return to normal immediately - Don't wait for January 1st or "next Monday"
- No dramatic restriction - Just resume regular eating patterns
- Remove remaining treats - Give away or dispose of leftover chocolate. Out of sight, out of mind
- Resume normal movement - Get back to whatever exercise you normally do
- Be patient - Water retention from increased carbs and salt will resolve within a week
The Bigger Picture
Christmas is, at most, a few weeks of your year. If you eat well most of the time, a period of festive eating won't significantly impact your health. Bodies are resilient. Weight fluctuates naturally.
The anxiety and guilt around Christmas eating often does more harm than the food itself. Stress affects digestion, sleep, and our relationship with food. Enjoying celebrations fully, without restriction or punishment, is genuinely the healthier approach.
The Bottom Line
Christmas weight gain is real but modest - typically 0.4-1.2kg, not the 5-7 pounds we're told to fear. The January crash diet usually fails and can make things worse. A better approach: enjoy the festivities, maintain some structure, and simply return to normal eating afterward. No drama, no detox, no guilt.
References
- Yanovski JA, et al. (2000). A Prospective Study of Holiday Weight Gain. New England Journal of Medicine
- Helander EE, et al. (2016). Weight Gain over the Holidays in Three Countries. New England Journal of Medicine
- Mason F, et al. (2018). Effectiveness of a brief behavioural intervention to prevent weight gain over the Christmas holiday period. BMJ
- Norcross JC, et al. (2002). Auld lang syne: Success predictors, change processes, and self-reported outcomes of New Year's resolvers and nonresolvers. Journal of Clinical Psychology
