Being Cold Increases Calorie Burn—and Appetite

Being cold burns calories. That part is true.

If you’ve ever done a cold plunge, gone for a winter walk underdressed, or cranked your thermostat down to save on heating costs, you’ve felt it happen. The moment cold hits, your body scrambles to protect itself.

That scramble costs energy.

To maintain core temperature, your body turns on a few powerful systems. Muscles begin to shiver, contracting rapidly to generate heat. Brown fat—specialized tissue designed specifically to produce warmth—ramps up non-shivering thermogenesis. Both processes increase calorie burn.

This is where the internet tends to get excited.

If cold exposure burns more calories, then surely it must help with fat loss… right?

Not so fast.

Human bodies don’t like being tricked. Any time energy expenditure increases, the body looks for ways to restore balance. That’s why exercise alone often disappoints people chasing weight loss. Burn more, and the body quietly pushes back—often through hunger.

A new controlled study set out to see exactly how strong that pushback is when people are exposed to mild cold.¹

What the science looked like

Researchers recruited 47 adults with an average age of 37 and an average BMI in the obese range. Each participant completed four separate 24-hour stays inside a metabolic chamber—a sealed room that precisely measures calorie burn.

During each stay, two things changed.

First, temperature. The room was either kept comfortable (74°F) or mildly cold (66°F)—cold enough to activate heat-producing mechanisms without triggering shivering.

Second, food access. In some conditions, participants received meals matched exactly to their calorie needs. In others, they had free access to a personalized vending machine stocked with foods they personally selected.

This crossover design meant every participant experienced every condition, making the results far more reliable than simple group comparisons.

What actually happened

Cold exposure did increase calorie burn. No surprise there.

But when participants were allowed to eat freely, they consumed about 400 extra calories per day in the cold—roughly a 13% increase.

Here’s the important part:

The extra eating had nothing to do with how many extra calories they burned.

Some people burned more but didn’t eat much more. Others barely increased metabolism yet ate significantly more. There was no neat, mathematical compensation.

Instead, cold appeared to flip a more ancient switch: conditions are harsh—eat.

Even though participants didn’t consciously report feeling hungrier, their hormones told a different story.

Ghrelin (which stimulates appetite) increased.

Leptin (which signals fullness) decreased.

From an evolutionary perspective, this makes perfect sense. Cold historically meant higher energy demands and uncertain food availability. Eating early and eating more would have been protective.

Researchers also noticed a delayed effect. Participants who relied more heavily on carbohydrates for fuel during cold exposure tended to eat more the following day, suggesting a secondary, fuel-specific hunger signal.

In short, cold didn’t just increase calorie burn. It increased appetite—immediately and, for some people, later on as well.

What this means in real life

This study reinforces a reality many people learn the hard way: strategies that increase calorie burn often come with biological consequences.

Cold exposure isn’t a weight-loss hack. It’s a stressor. And when the body senses stress, it doesn’t politely ignore it—it responds.

Another important factor here is the food environment. When participants had access to a vending machine filled with highly palatable options, eating more became easy. Variety, convenience, and reward stacked the deck.

That matters, because increased hunger is not a moral failure. It’s biology meeting opportunity. A kitchen stocked with protein-rich meals and minimally processed foods creates a very different outcome than one filled with snack foods and sweets—especially when appetite signals are already amplified.

Cold didn’t “break” willpower in this study. It exposed how powerfully environment and biology interact.

Closing Thoughts

After 15 years of working with people in every stage of life, this pattern shows up again and again. Whenever the body senses threat—whether that threat is cold, stress, lack of sleep, or aggressive calorie restriction—it responds predictably. Hunger rises. Cravings sharpen. Decision-making gets harder.

What still amazes me is how often people blame themselves for these responses instead of recognizing them for what they are: survival systems doing their job.

I’ve watched clients make far more progress by respecting these signals than by trying to outsmart them. When stressors are acknowledged and food environments are shaped intentionally, the struggle eases. Health stops feeling like a battle and starts feeling like alignment.

Your health is your wealth – Michael Beiter

Personal Trainer

Nutrition, Sleep, Stress Management, and Recovery Coach