Chill--and Lose Weight
There are a thousand reasons to curse winter: blizzards and shoveling, cancelled flights and shivering, among other things. If you find yourself longing to wake up tomorrow sweating in Hawaii, take heart: there's at least one new reason to celebrate cold temperatures. Cold, it turns out, may help you to lose weight. The finding flies in the face of conventional wisdom that tells us that our bodies are programmed to put on a few pounds in colder weather to insulate us from the elements.
The news comes from a paper just published in the journal Trends in Endocrinology & Metabolism, which indicates that we burn more calories when the mercury drops.1 But there's a catch. The research doesn't explore the effect of truly frigid outdoor temperatures; rather, it notes that regularly turning the thermostat down inside the house is a positive step for weight loss.
The authors of the paper explain that they undertook the study, "Because 90% of the time we are exposed to indoor conditions, [and so] health aspects of ambient temperatures warrant exploration. What would it mean if we let our bodies work again to control body temperature?"2 The "work again" reference hails back to the fact that until modern times, houses generally stayed cool during the winter because central heating didn't exist. To stay warm, the body had to work to generate internal heat, burning calories in the process.
How does cold activate weight loss?
First, when we experience extreme cold, we shiver and that burns calories. But in this new research, the scientists contend that even if we don't shiver--in other words, if we're exposed to temperatures that are not even cold but just slightly cool--we activate our brown fat. Brown fat differs from the white fat we normally think of as associated with obesity. As Jon Barron explained several years ago, brown fat specializes in burning white fat (the fat you want to get rid of) for heat energy.
Dr. Mitchell Lazar, chief of endocrinology at the University of Pennsylvania, says, "There is certainly evidence in people as well as rodents to suggest that reducing temperature makes the body burn more calories to keep up body temperature." The study authors assert that cold conditions "can significantly affect our energy expenditure over sustained time periods."
Earlier studies that explored the effect of cold temperatures on body metabolism also found the weight loss connection. One recent Japanese study, for instance, found that subjects lost body fat after spending two hours a day for six weeks at a temperature of about 63 degrees Fahrenheit. Other studies show that the body adjusts to the cooler temperatures with increased exposure to it, triggering more brown fat burning. A Dutch study discovered that after spending six hours a day at 59 degrees Fahrenheit, participants acclimated and shivered less, meaning their metabolisms had become more efficient. Study author Wouter van Marken Lichtenbelt explains, "[This] 'cold-temperature training,' also known as 'acclimatization'…has been shown to rev up brown fat in rodents, and it seems possible that it could do the same in people."3
As simple a diet measure as it seems to turn down the heat, don't think that you'll end up svelte just by doing so.
"More frequent cold exposure alone is not going to save the world [from obesity]," says Dr. Lichtenbelt, "but it is a serious factor to consider for creating a sustainable environment along with a healthy lifestyle."
The good news is that some people who have been procrastinating about going to the gym might finally don their athletic clothes when faced with the choice of either working out or sitting inside in 59 degree temperatures. We like to stay warm and cozy. And another benefit of exercise as Jon explained in his discussion of brown fat is that brown fat is derived from muscle. If you exercise, you increase the amount of muscle and brown fat -- improving your ability to burn off calories. That's what we call a twofer for exercise.
On the other hand, before you give up your Hawaii dream in favor of some place cool, like Seattle or Anchorage, consider that a separate study just found that sunshine lowers blood pressure. According to an article just published in the Journal of Investigative Dermatology, researchers from the Universities of Edinburgh and Southampton in Great Britain found that exposing subjects to 30 minutes of sunshine dilated their blood vessels, increased levels of nitric oxide, and led to blood pressure drops. 4
The scientists warn that simply standing out in the sun isn't going to cure hypertension any more than freezing in a cold room will cure obesity. At most, you'll get a little boost from these things. The bottom line is that dietary discretion and exercise are the best tools in your arsenal for maintaining health, though a dose of sunshine followed by a chilly indoor adventure can't hurt.
- 1. Lichtenbelt, Wouter van Marken et al. "Cold exposure--an approach to increasing energy expenditure in humans." 2014. Trends in Endocrinology and Metabolism. 23 January 2014. http://download.cell.com/images/edimages/Trends/EndoMetabolism/tem_932.pdf
- 2. Rehel, Jason. "Cooler temperatures may help shed excess weight, increase calorie-burning brown fat: Holland study." 23 January 2014. National Post. 23 January 2014. http://life.nationalpost.com/2014/01/23/cooler-temperatures-may-help-shed-excess-weight-increase-calorie-burning-brown-fat-holland-study
- 3. Marcus, Mary Brophy. "Could Turning Down the Thermostat Help You Lose Weight?" 22 January 2014. Web MD. 24 January 2014. http://www.webmd.com/diet/news/20140122/could-turning-down-the-thermostat-help-you-lose-weight
- 4. Castillo, Michelle. "Sunshine may chase the blood pressure woes away." 23 January 2013. CBS News. 24 January 2013. http://www.cbsnews.com/news/sunshine-may-chase-the-blood-pressure-woes-away