We all know how important taking a walk in Nature is for our physical, mental, and emotional health. And yet, if you live in a cold climate, February can be the cruelest month for a walk around the neighborhood—or just leaving the house in general.
But a pair of new studies shows that if you make the effort to get outside when the temperatures drop, you may actually drop some pounds as well.
That’s right—the studies found that just being outside in the cold for a short period of time can help you burn 15 percent more calories than if you stayed inside. And surprisingly, it all has to do with vitamin A production.
What cold does to your body’s fat
Last July, Austrian researchers published a study showing that short exposure to cold weather may help people with brown fat burn 15 percent more calories than people who don’t have any brown fat.1
To help make sense of this, it’s necessary to understand the two types of fat your body makes.
More than 90 percent of human fat is typically white fat. This stores energy and helps keep your organs warm. But too much white fat leads to obesity.
Meanwhile, brown fat is “good” fat. The more you have, the less likely you are to struggle with being overweight—and all of the chronic diseases associated with obesity.
Babies are born with brown fat, but it can disappear as we age. Like white fat, brown fat stores energy. But unlike white fat, brown fat literally burns calories to make heat, through fatty acid oxidation and caloric production.
The good news is, over the years, scientists have discovered that it’s possible to actually turn white fat brown. One potential way is through moderate exercise. And another way is through cold exposure.
Which leads me to the second new study…
The missing ingredient: Vitamin A
After they published their July study, the Austrian scientists did more research on how cold exposure helps us burn more calories. What they discovered was surprising…
Low temperatures appear to increase vitamin A production in both humans and animals. And that allows us to burn more calories when the temperatures fall.
Here’s how it works. Most of our bodies’ reserves of vitamin A are stored in the liver (as with vitamin D). Cold exposure appears to send vitamin A from the liver out to fat tissues, where it stimulates conversion of white fat to brown fat—triggering a high rate of calorie burning and heat generation.
And that, of course, helps you lose weight…or helps slams the brakes on becoming overweight in the first place.
My two-step plan for winter weight loss
So, what we’ve learned from these new studies is that the “old wives’ tale” that going out in the cold causes your body to burn fat for heat is actually true. But your body needs vitamin A to make it all happen.
So rather than cocoon inside when the temperatures plummet, here’s what I suggest you do instead to manage your weight and stay healthy:
1.) Walk through the winter wonderland. As we just learned, even a few minutes of outdoor, cold-weather activity can be highly beneficial. Remember, science consistently shows that 140 to 150 minutes total per week of light-to-moderate exercise does the trick for health and longevity—without wearing down your heart, joints, eyes, gastrointestinal tract, or genitourinary system like excessive exercise can.
Your weekly exercise doesn’t need to be done daily, all at once, or in a sweaty, indoor gym. Instead, why not do something fun outdoors, like ice skating, sledding, tobogganing, building a snowman, or simply strolling and communing with Nature?
2.) Eat your vitamins. Because vitamin A is fat soluble, I don’t advise taking supplements. (You can actually build up too much in the fat stores in your body if you supplement too much.) Instead, I recommend you get vitamin A directly from your diet.
Fortunately, that’s easy to do. There are plenty of foods rich in vitamin A, including eggs, meat, fish, and dairy. Plus, yellow and orange fruits and vegetables like sweet potatoes, pumpkin, squash, carrots, and cantaloupe are loaded with carotenoids (as I discuss on page 7), which your body naturally and safely converts to vitamin A.
I’ve long said that we need a more sophisticated understanding of how the body works when it comes to fitness and weight loss. And studies like these are helping improve our knowledge…and hopefully our actions.
1“The Presence of Active Brown Adipose Tissue Determines Cold-Induced Energy Expenditure and Oxylipin Profiles in Humans.” J Clin Endocrinol Metab. 2020 Jul 1;105(7):dgaa183.
2“Intact vitamin A transport is critical for cold-mediated adipose tissue browning and thermogenesis.” Mol Metab. 2020 Sep 28;42:101088.