Why People Are Braving the Cold as the Next Dieting Tool

— -- There has been plenty of news about brown fat. Its scientific name is brown adipose tissue and it’s thought that when stimulated by cold it revs up our body’s ability to burn calories.

So now a rush of new theories, products and services that say braving the cold, among other things, will burn extra calories.

To try this out, I start at KryoLife in New York City. On an upper floor in Midtown Manhattan, the company charges $90 a session to let you step into a chamber that uses air cooled by nitrogen gas to create a dry, negative 254 degrees environment.

They make you wipe down your entire body before you go in so there is no exposed skin that is moist. But the second the cold air hits, it is shocking. My first revelation: “I’m cold in places I’ve never been cold before.”

I wear mittens and socks and clogs, but not much else. I only stay in for three minutes, which is the amount of time the company says has several health benefits, mostly anti-inflammatory.

“It's a great supportive tool for weight loss and spring is coming," said KryoLife CEO Joanna Fryben.

Fryben explained that she is not aware of any studies on whether short bursts of exposure to cold, like those experienced at KryoLife, can burn extra calories. However, there have been studies showing that lengthy exposure to cold can result in additional calorie burning.

So you may be asking, why not just brave the elements?

I strip down to shorts and a long-sleeve t-shirt to spend 30 minutes in Central Park on a 26-degree day. I try to keep warm by jumping up and down (and certainly that burned some extra calories) and after a very foolish decision to do snow angels without gloves on, I reach the point of this whole exercise.

My hands are so cold that they’ve gone from pins and needles to excruciating pain. Maybe my jog was a bad idea. When does boosting your metabolism turn to hypothermia frostbite or worse? Do not try this at home.

So, I turn to a more moderate approach, the Cold Shoulder Calorie Burning Vest. It is a Kickstarter product designed by a visiting scientist at NASA's Jet Propulsion Laboratory that is basically a vest full of ice packs.

The company says wearing it for as much as three hours a day could burn up to an extra 500 calories. It certainly is less jarring than my previous two endeavors. In fact, it is kind of comfortable.

After trying on the Cold Shoulder, I head to the kinesiology lab at San Francisco State University where Professor Matt Lee has agreed to compare how many calories I burn normally versus how many while wearing the Cold Shoulder. First, I lay down for 20 minutes. Then, Lee conducts a 20 minute calorimetry test on me: I’m wearing a canopy that captures all of the CO2 I expend that will determine how many calories I am burning. I look like an astronaut.

Next, I put on the Cold Shoulder vest, wait for five minutes and start another 20 minute calorimetry test.

It turns out I expend about 1.4 kcals a minute normally and, when we add in the ice, I burn an average of 1.5 kcals a minute. Lee calculates that is about a 7 to 8 percent differential.

Even if I wore the vest for three hours, Lee said that would not directly add up to the 500 calories a day that the Cold Shoulder makers say their product burns.