At this writing, plenty of Americans – in the East, Midwest and even the South — are enduring the winter of 2014-2015 chills. And so what do we do when the mercury plummets? Turn up the thermostat, of course! You see, we modern Americans have been programmed to crank up the heat in the winter.
But could our cozy centrally heated houses be making us fat? Scientists say yes and posit that simply turning down the heat a few degrees might help us lose a few pounds without diet or exercise. The connection between ambient temperature and weight is not as crazy as it might sound.
We all know that when we’re exposed to extreme cold, we shiver, which makes our muscles contract and generate heat. And that in turn burns extra calories. But now research indicates that even in mildly cold conditions, say in a room with the thermostat turned down to the lower 60s, people will burn extra calories – without shivering.
Igniting Your Wonder Fat
This process is called non-shivering thermogenesis. It involves what’s called “brown fat,” that can be found in certain areas of our bodies, including the upper back and side of the neck. Unlike normal fat, which is the depository for excess energy and calories, brown fat is like an internal furnace that burns lots of calories/energy. Cooler ambient temperatures are the trigger that ignites the brown fat furnace to keep you warm.
According to Atlantic Magazine, the notion that thermal environments influence human metabolism dates back to studies conducted in the late 18th century by the French chemist Antoine Lavoisier, but only in the past century has it become relevant to daily life.
The New York Times reported on this topic, referencing a study featured in the journal Obesity Reviews.
“The researchers found that since central heating became commonplace in the 1960s, room temperatures have increased slowly but steadily in both the United States and Britain. In both countries, obesity has also been on the rise,” the article states.”
One of the study’s lead authors, Fiona Johnson, University College London, discussed the study in the New York Times article.
“What’s particularly noticeable is that people are heating the whole of their house. In the past they would heat the main living areas, and the bedrooms might be cold at night.”
To make things even worse, we travel in heated cars and rarely spend time outside walking or recreating in the cooler temps. Dr. Johnson believes all this warm indoor time, is decreasing our brown fat levels. She explains it as a ‘use it or lose it’ scenario.
“If you’re not exposed to cold, you’re going to lose your brown fat, and your ability to burn energy will be affected. But you can get it back,” she explains.
Bringing “Winter” Back
Ray Cronise, a former NASA scientist, specializes in researching the benefits of cold exposure, and has dubbed it the “Metabolic Winter” hypothesis. Cronise and fellow scientists believe that obesity is not completely due to lack of exercise, but also a one-two punch of chronic overnutrition and chronic warmth.
According to the Atlantic article on the topic, seven million years of human evolution were dominated by two challenges: food scarcity and cold.
“Maybe our problem is that winter never comes,” Cronise and his colleagues wrote in a scientific report.
But the good news is a growing body of research on the metabolic effects of cold exposure, says you can gain active brown fat without suffering too much. In fact, just cooling bedrooms from 75 degrees to 66 degrees, helped participants in one study gain brown fat.
Additionally, a recent study in The Journal of Clinical Investigation, revealed that people who spend two hours a day in mild cold (around 63 degrees) for six weeks burned more energy than people who spent the time in warmer temperatures.
So, next time you are lamenting the chilly temps, consider the metabolic benefits. And you might just toss off that extra blanket to find a slimmer you!