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Why Do We Gain Weight in Winter: 8 Key Factors

Written by Andrew Le, MD

UpdatedNovember 28, 2023

Winter brings holidays and fun times. But the cold weather can also lead to weight gain, known as "winter weight gain." As it gets colder and we celebrate more, habits change in ways that spur gaining a few pounds. The reasons are complex, more than just eating more treats.

Research shows people gain about 1-2 pounds on average between late September and March. This gradual gain seems small but adds up over the years.

The dark winter months bring changes that disrupt even healthy lifestyles. From hormone shifts to holiday feasting, many factors increase appetite, decrease activity, and promote weight gain when cold.

In this article, we will explore why we gain weight in winter and learn how to avoid it. By understanding the causes, you can stay proactive during this season.

🔑 Key Takeaways

  • Winter weight gain is a real phenomenon caused by behavioral, physiological, and environmental changes like decreased sunlight, hormonal shifts, and holiday feasting.
  • Research shows limited sun exposure in winter allows fat cells to store more fat, directly contributing to weight gain.
  • Holiday meals and treats typically overload calories, with adults gaining an average of 0.4-0.9 kg (0.88 to 2 lbs) from November to January.
  • Increased melatonin and altered sleep patterns in winter stimulate appetite and cravings, promoting overeating.
  • Physical activity drops significantly in winter as motivation to exercise outdoors declines in cold weather.
  • Excessive alcohol consumption packs on empty calories and disinhibits diet, contributing to winter weight gain.
  • Holiday stress leads to hormonal changes that increase cortisol and visceral belly fat.
  • Despite healthy eating resolutions in January, most people's diets remain skewed towards processed junk foods after the holidays.
  • Strategies like indoor workouts, sleep hygiene, mindful eating, moderating alcohol, managing stress, and meal prepping can help avoid gaining winter weight.
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Key Factors That Lead to Weight Gain During Winter

Losing weight is never easy, and the struggle intensifies when the weather turns cold. Research shows that weight increases more during the fall and winter than in summer. This is due to multiple factors contributing to increased calorie intake and decreased calorie burning during the colder seasons.

To better understand this seasonal phenomenon, here are some of the primary drivers and some tips on avoiding winter weight gain:

1. Decreased Sunlight Exposure

Research from the University of Alberta made an interesting discovery about sunlight’s effect on fat cells.

The study found blue light from the sun caused fat cells near the skin to shrink and store less fat. The scientists suggest that limited sun exposure in winter allows these subcutaneous fat cells to store more fat.

It's still unclear precisely how much sunlight is needed to trigger fat shrinking. More research could also explore whether greater sun exposure in infancy impacts fat cell behavior later in life. However, the preliminary findings indicate a lack of sunlight in winter supports weight gain by improving fat cells' fat storage capacity.

2. Holiday Feasting and Treats

The holiday season from late November into the New Year brings social gatherings and family events. These celebrations usually center around plentiful, high-calorie meals stacked with traditional favorites like:

  • Mashed potatoes
  • Meat roasts
  • Eggnog
  • Pies
  • Other sweet treats

A study in the New England Journal of Medicine showed that adults in America typically gain about 0.4 to 0.9 kg (0.88 to 2 lbs) between November and January, primarily due to increased caloric intake. The abundant food options and jovial party mood make it easy to overindulge. But this minor weight gain accumulates and often persists long after the holidays.

To avoid holiday feasting pitfalls and gaining weight in the winter, use strategies like portion control, filling up on fruits/veggies first, and preventing rushed meals. Planning alternative activities centered solely around food can also help curb overeating.

3. Hormonal Changes

The darker, colder days of winter trigger hormonal changes that stimulate appetite and fat storage. One key player is melatonin, which regulates sleep-wake cycles and increases by up to 80% in winter.

Higher melatonin is linked to:

  • Greater appetite
  • Cravings for sugary and high-carb comfort foods
  • Potential weight gain

Disrupted sleep patterns from longer winter nights may compound these urges to eat more calories.

As we age, natural decreases in hormones like estrogen and testosterone also slow metabolism, making it easier to gain and more challenging to lose weight. The combined impact of these hormonal shifts and a more sedentary winter lifestyle sets the stage for expanded waistlines.

To counteract these hormonal changes, ensure adequate sleep, exercise regularly, practice stress management, and consume a balanced, nutrient-rich diet.

💡 Did You Know?

Hypothermia typically occurs in winter but can also happen in temperate climates. According to the CDC, it is most common in older adults with insufficient heating or food, infants in very cold environments, and individuals exposed to the elements, such as the homeless or those engaged in outdoor activities like hiking. Learn more about this in our article about the causes of cold skin.

4. Decreased Physical Activity

Frigid temperatures and earlier sunsets make outdoor exercise unappealing for many during winter. Research by Gallup and Healthways verified that physical activity drops substantially in December, bottoming out for the year.

The prospect of getting cozy inside, watching TV, and staying warm trumps motivation for most people to bundle up and be active outdoors or go to the gym.

To maintain exercise habits, explore enjoyable indoor activities like dance workouts, yoga, home aerobic exercise, or recreational sports. Seeking support from workout partners, taking group fitness classes, and using home equipment like stationary bikes can also keep you active when it’s cold outside.

5. Excessive Alcohol Intake

The merriment of holiday parties often involves increased alcohol consumption. While the relationship between alcohol and weight gain depends on the type and quantity consumed, excessive intake contributes to expanding waistlines.

Alcohol is high in calories, providing about 7 calories per gram. Sugary mixed drinks and distilled spirits like whiskey pack the biggest caloric punch. Light to moderate intake of certain drinks like red wine generally poses less risk for weight gain. However, heavy, frequent drinking is often associated with added pounds, especially in the belly region.

To reduce alcohol’s impact on your weight, be mindful of drink calories by opting for lighter choices like wine spritzers or low-calorie beer. Alternate alcoholic drinks with water and limit overall consumption by setting a maximum drink limit at gatherings.

6. Too Much Sleep

When cold weather makes you want to crawl back into bed, your motivation to work out often declines too.

One study showed that long sleep duration, defined as greater than 9 hours, is associated with higher odds of obesity. The research indicates a 1.57 times higher obesity rate in individuals with long sleep duration. Interestingly, this association is not found in the male population.

Additionally, among the female population, long sleep duration is linked to a 1.70 times higher prevalence of obesity. These findings highlight a potential correlation between extended sleep and an increased likelihood of obesity, particularly among women.

To prevent oversleeping, maintain a regular sleep-wake schedule, even on weekends. Prioritize getting adequate rest within the recommended 7-9 hour range, but avoid too much sleep, which can disrupt your body’s circadian rhythm.

7. Holiday Stress

Beyond dietary and lifestyle factors, holiday stress also contributes to winter weight gain.

Financial strain, family demands, returning to work after vacation, and post-holiday blues can all amplify stress. Heightened stress leads to the release of hormones like cortisol and adrenaline, which increase belly fat storage.

Using stress management techniques like meditation, yoga, deep breathing, and seeking emotional support can mitigate stress responses. Organizing holiday tasks and finances early on can also limit last-minute stress.

8. Unhealthy Eating Patterns

Despite ambitions to eat healthier in the new year, research reveals most people’s grocery purchases remain skewed towards unhealthy foods post-holidays. Even as sales of fresh produce rise in January, shoppers continue buying high-calorie processed items at holiday levels. Old habits die hard after excessive holiday indulgence.

To encourage nutritious eating, meal prep healthy snacks and dishes in advance and shop with a list to avoid impulse junk food buys. Incorporate simple diet tweaks like choosing Greek yogurt over sour cream or whole grain bread over white. Enlist a friend to discuss healthy goals for mutual encouragement and accountability.

📔 Related Articles

Explore additional weight management topics by browsing some of our articles:

Final Thoughts

While colder weather encourages overeating and inactivity, you can override these impulses with mindset adjustments and positive habits.

Winter holidays signify a time for merriment and indulgence. But moderation, managing stress, proper sleep, regular exercise, and nutritious eating choices can help you avoid significant weight gain.

By committing to your health and well-being this winter, you can feel energized, balanced, and ready for every season. With the right lifestyle strategies, those stubborn seasonal pounds don’t stand a chance.

FAQs on Why Do We Gain Weight in Winter

Is it normal to gain weight in the winter?

Yes, it's pretty normal to experience weight gain during the winter. Research indicates that weight tends to increase more in the fall and winter months compared to summer. Additionally, body weight often peaks in winter and is maintained throughout the rest of the year.

Why do I gain weight in the winter?

The drop in temperature can lead to a decrease in motivation to stay active, a common factor contributing to winter weight gain. Moreover, the winter season is marked by holidays, weddings, and festivals, creating situations that may promote overeating, sedentary behavior, and the consumption of calorie-rich foods.

Illustration of a healthcare provider asking questions on a smart phone.
Virtual weight loss solution
A personalized GLP-1 medication program (eg. Wegovy, Ozempic), delivered to you via our partner Korb Health
Illustration of a healthcare provider asking questions on a smart phone.
  • Free consultation; program starts at $269/mo
  • Checkmark Inside Circle.Customized online program and wellness coaching
  • Prescription medications and supplies shipped to your door