Not because of the holidays themselves. In a study that weighed 195 adults before, during and after the season, the average gain was less than a pound. The problem is that it didn’t come back off, and that most people stop training “until things calm down,” then start January further back than they ended October.
It’s the first week of November. Count forward. There are about eight weeks left in the year.
For most people over 40, those eight weeks are already spoken for. Thanksgiving. Travel. Year-end at work. Parties, school events, family in town. And somewhere in the back of your mind, a quiet decision has already been made: I’ll get serious in January.
That decision costs more than the holidays ever will.
What the Holidays Actually Do
Most people believe the season puts five pounds or more on the average adult. Researchers tested that. They weighed 195 adults before, during and after the holidays (Yanovski et al., 2000).
The average gain from mid-November to early January was less than a pound.
That’s the good news. Here’s the part that matters: it didn’t come back off. Through spring and into summer, the weight stayed. The researchers concluded that this small yearly gain likely feeds the slow weight creep so common in adulthood.
So the holidays aren’t a cliff. They’re a ratchet. A little each year, and it never clicks back.
The holidays aren’t a cliff. They’re a ratchet.
The Real Loss Isn’t the Pound
The pound is the part you can see. The bigger cost is what happens to everything else when you decide the year is over.
You stop training “until things calm down.” Sleep slides because the calendar is full. The walks stop because it’s cold and dark by 5:30. By the time January arrives, you aren’t starting from where you were in October. You’re starting further back, with a plan built for a life that only exists on paper.
That’s the all-or-nothing trap. It sounds responsible: why start now when I’ll just get derailed? But it treats your health like a project with a start date, when it’s something you carry every single day.
Eight weeks is about 15% of the year. Write it off every year from 40 to 70, and that adds up to more than four and a half years.
Minimum Beats Nothing
You don’t need December to be your best month. You need it to not be a zero.
A large recent review pooling 67 training studies found that the returns on extra weekly training flatten out, and they flatten fastest for strength (Pelland et al., 2026). The first work you do in a week counts the most. That’s the same reason a 20-minute workout still counts.
A short week still counts. Two short sessions in a hectic week keep you in the game. Zero sends you back to the start line.
You don’t need December to be your best month. You need it to not be a zero.
There are two kinds of people walking into January. One is starting over, again. The other is picking up right where they left off. The difference isn’t a calmer season. It’s deciding the season doesn’t get to make the call.
Check Yours This Week
Your calendar. Look from now to January 1. Find the weeks you’ve already written off in your head.
Your floor. Name the one thing you kept doing during your last chaotic stretch. That’s your floor.
Your plan. Is it built for the life you have in November, or the life you’re hoping for in January?
Where to start, and how much is enough for your season, is what we set for each client.
Sources
- Yanovski JA, Yanovski SZ, Sovik KN, Nguyen TT, O’Neil PM, Sebring NG. (2000). A Prospective Study of Holiday Weight Gain. New England Journal of Medicine. doi:10.1056/NEJM200003233421206 PMID 10727591.
- Pelland JC, Remmert JF, Robinson ZP, Hinson SR, Zourdos MC. (2026). The Resistance Training Dose Response: Meta-Regressions Exploring the Effects of Weekly Volume and Frequency on Muscle Hypertrophy and Strength Gains. Sports Medicine, 56(2), 481–505. doi:10.1007/s40279-025-02344-w PMID 41343037.
About this evidence. The holiday study weighed a convenience sample of 195 adults in the United States, measured body weight only, and was published in 2000. The average holiday gain was 0.37 kg (under a pound), and the net gain from fall to late winter was 0.48 kg. The training review combined 67 studies of mostly young men and counted weekly sets, not minutes. The arithmetic on eight weeks per year is our own. Applying both findings to the holiday season is judgment, built on 25 years of coaching.
This article is educational and is not medical advice. If you have heart or joint concerns, talk to your physician before adding strenuous training.
Also published in Built to Endure, our free weekly publication.