While the body does indeed respond to cold, it doesn’t always do so in the way we imagine. And the biggest influence on body weight is still how much we eat and how much we move — not the number on the thermometer.
Why We Feel Like We Burn More Calories in Winter
Logically, it makes sense. It’s cold, the body doesn’t want to get chilled, so it has to produce more heat. This is where brown fat, cold exposure, and winter swimming are often mentioned, as they show how the body reacts to cold and why people talk so much about a “boosted metabolism.”
The body really does have several ways of defending itself against the cold. When ambient temperature drops, resting energy expenditure increases — meaning the energy we burn even at complete rest. In some people, brown fat is also activated. Unlike regular fat, brown fat produces heat instead of storing energy.
The problem is that modern life protects us, perhaps too well. We wear warm clothes, overheat our homes, and come into contact with real cold only minimally. As a result, the body’s natural “winter mode” is no longer as strong as it once was.
What Science Says
More recent studies confirm that differences between winter and summer do exist — but they are not large enough on their own to lead to weight loss.
A large study from South Korea, for example, showed that resting energy expenditure was about 5–14% higher in winter, depending on age and body fat levels. Younger and leaner individuals responded to cold with a more pronounced increase in metabolism than older participants.
Similar seasonal fluctuations have also been observed outside Asia, including in Europe and North America. One study found that total daily energy expenditure differed very little between winter and summer because modern environments significantly blunt the body’s natural response to cold.
Even here, although metabolism was slightly more active in winter, diet and physical activity easily outweighed the difference.
Put simply, we may burn a little more in winter — but the difference is small. And if we eat more and move less at the same time, the result can be exactly the opposite.
Why We Gain Weight Even Though We “Burn More”
In practice, winter tends to be a season of weight gain rather than weight loss. A 2021 meta-analysis confirmed that body weight peaks for most people during the winter months. Similarly, studies on people actively trying to lose weight showed that they most often gained weight from autumn into winter.
This is no mystery. In winter we crave more filling foods, walk less, drink alcohol more often, stay comfortably warm indoors, and face darkness and cold outside.
What About Cold Exposure?
Yes, cold can activate brown fat, which burns energy to produce heat. The question is how big an impact this has in real life.
A 2024 systematic review confirmed that mild cold exposure increases the use of free fatty acids and activates brown fat. The body therefore burns slightly more energy as it tries to stay warm. However, these changes were not dramatic — they did not lead to significant fat loss or a large increase in total daily energy expenditure.
Cold exposure can therefore be a nice bonus, but it is certainly not a strategy that will meaningfully drive weight loss on its own.
How to Use Winter to Your Advantage
Winter doesn’t have to be a time when everything slows down and the kilos quietly creep up. If you know how to work with colder weather, it can become more of a helper than an obstacle.
Go Outside and Use the Cold as a Mild Booster
Brisk walking in cooler weather increases energy expenditure slightly more than the same walk in summer. It doesn’t have to be extreme — short walks, a fast walk to work, or 15–20 minutes outside between daily obligations is enough. Cold stimulates the body, gives you more energy, and improves mood thanks to better oxygenation and natural light.
Related: Why Running in Winter Can Be the Best Thing You Can Do for Your Body
Watch Portions — Even When You Crave “Winter Foods”
In winter, most people unknowingly eat a bit more — in some studies, even hundreds of extra calories per day. This is natural.
We crave warm, heavier, and sweeter foods, drink alcohol more often, and easily justify “treating ourselves.” You don’t need to ban anything, but it pays to eat more mindfully, increase protein and fiber intake, and keep portions under control — especially in the evening.
Training Is Not Seasonal
Winter is often the time when people struggle most to stay consistent with exercise — yet this is where the biggest difference is made.
Maintaining a regular training routine is far more important than hoping the cold will burn calories for you. Strength, muscle, and conditioning are built gradually, and the body values consistency more than occasional heroic efforts.
Think of Cold Exposure as a Bonus, Not a Magic Shortcut
Cold showers or brief cold exposure activate brown fat and slightly increase energy expenditure, but this is a bonus rather than a primary strategy. Cold exposure may improve circulation, mood, and stress resilience, but it cannot replace training or a quality diet. Treat it as a supportive tool, not the foundation of fat loss.
Focus on Better Sleep Quality
Winter often disrupts sleep rhythms. There is less daylight, darkness comes earlier, and the body may feel more fatigued.
Quality sleep strongly affects hunger regulation, energy expenditure, and cravings for sweets. When we sleep well, the body manages energy better and stores less fat.
Related:
How to Lose Fat Without Losing Muscle
How Does Sleep Deprivation Affect Your Health and Performance
