Can You Lose Weight By Turning Down the Heater?
Humans are warm-blooded, which means we need to keep our blood warm to stay alive. And what keeps your blood and other tissues warm? Burning fuel! Or more specifically, calories.
The colder your environment is, the more calories your body needs to burn in order to keep warm. But does that mean you can “hack” your metabolism and burn a few extra calories by turning off the heater?
How does brown fat and shivering help with weight loss?
One of your body’s first reactions to cold exposure is shivering. Conveniently, shivering increases body heat production, which helps you burn additional calories. As you shiver, your body also works on drawing heat away from the skin, toward the core. But that’s not the only way it responds to cold temperatures—researchers also discovered that cold exposure helps your body produce brown fat.
Humans have two kinds of fat tissue: white and brown. White adipose tissue is used for energy storage, while brown fat, the science-y way of saying brown fat, is used to produce heat. Brown fat hosts a multitude of mitochondria, that use something called uncoupling protein (UCP1) to skip the energy-producing step (the production of adenosine triphosphate) and uses the fuel to produce heat instead. Brown fat is particularly important for infants, as it keeps them warm during a fragile period of life.
Most of our brown fat is located around the shoulder blades and neck. It only shows up on PET scans when it’s been activated, which is to say, when we’ve been exposed to the cold.
One important thing about brown fat is that, while it is activated during cold exposure, it is also produced after cold exposure. During study trials, only a small number of participants couldn’t develop (much) brown fat after cold exposure.
While a cold shower won’t build up brown fat stores, regular, long-lasting cold exposure can help the body develop additional brown fat. After consistent cold exposure, people don’t shiver as much because the additional brown fat stores help the body stay warm, while burning additional calories to do so.
Developing brown fat
Studies show that temperatures lower than 65°F help the body develop BAT stores. Some trials used temperatures as low as 59°F, though most people would find that uncomfortable for extended periods of time.
There is no standard protocol for testing cold exposure yet, so study results and methodology vary. One study showed a 37 percent increase in BAT volume after six hours of cold exposure at 60°F per day for ten days, but no increase in energy expenditure was observed. A shorter study using a protocol of three days at 61°F showed that increased cold exposure was associated with an additional 140 calories burned per day. So, it’s possible that warming back up after cold exposure may negate some of the benefits of cold exposure, but further research is needed to confirm this effect.
About half of daily calories are used to maintain core temperature, which is about 98.6°F. Extrapolating the results of these studies suggests lower room temperature could increase weight loss by 5-10 pounds per year, but additional long-term trials are needed to determine if this extrapolation is appropriate.
If being cold makes you want to eat more, cold therapy for weight loss won’t be a good option for you. Studies show that people tend to eat a little more when they’re cold. This is due to a biological urge to increase fat stores for added insulation. Plus, digesting food produces heat, which helps you warm up.
In one study, office workers exposed to temperatures of 68°F ate 100 calories more on average than workers in a 79°F environment. Studies conducted on animals suggest that colder temperatures also increases the desire for highly-palatable foods like junk food, since it is more effective at building fat stores.
Even though cold exposure can be a helpful tool in the weight loss kit, it’s important to pay attention to your cravings and avoid overeating.
Personal Preference Varies
The ability to handle cold can differ significantly from person to person. While some people are sensitive to cold temperatures, others can go outside during the winter in shorts and a T-shirt. This is why it’s important to consult with your physician before starting any type of cold therapy, especially if you’re sensitive to cold temperatures (as circulation problems or Raynaud’s phenomenon may be undiagnosed).
Older people should also be cautious when starting cold therapy, due to a higher risk of hypothermia and blood pressure issues. Remember, the health risks of extreme cold far outweigh any potential health benefits, so don’t try anything dangerous in an attempt to significantly lower your body temperature.
That being said, most adults don’t consider 65°F as extremely cold. Furthermore, as your body gets used to colder temperatures, you’ll begin to shiver less while continuing to burn calories to produce heat.
Turning down the thermostat can help slightly with long-term weight loss by increasing your brown fat reserves—as long as you’re not compensating by overeating. While losing 5-10 pounds a year is great, cold exposure is just one strategy for maximizing weight loss.
At the end of the day, it’s always a good idea to choose something you can stick to.