By Dr. Mercola
For a number of years, scientists have been studying "brown fat."
Brown fat is a heat-generating type of fat that burns energy instead of storing it, and this may have important implications when it comes to weight loss.
Human newborns have a supply of brown fat to keep warm, but by adulthood they lose most of their stores of it.
Brown fat has been located in the neck area, around blood vessels (helping to warm your blood), and "marbled" in with white fat in visceral fat tissue.
In a new study, scientists found that they were able to activate the brown fat still present in adult men by exposing them to cold temperatures.
The men burned more calories when cooled, and lost white fat, the kind that causes obesity.
According to the study's authors1:
"That adult humans possess brown fat is now accepted - but is the brown fat metabolically active? Does human brown fat actually combust fat to release heat?
... Ouellet et al. demonstrate that metabolism in brown fat really is increased when adult humans are exposed to cold.
This boosts the possibility that calorie combustion in brown fat may be of significance for our metabolism and, correspondingly, that the absence of brown fat may increase our proneness to obesity - provided that brown fat becomes activated not only by cold but also through food-related stimuli."
Research has shown that certain groups of people tend to have more brown fat than others, and there are direct correlations between the activation of brown fat and metabolic measures of good health. For example:
- Slender people have more brown fat than obese people do
- Younger people have more brown fat than elderly people, and
- People with normal blood sugar levels have more brown fat than those with high blood sugar
Cold Temps Boost Brown Fat Activation
Swedish research published in 2009 also found that cold temperatures increased the activity in the subjects' brown fat regions, measured using positron-emission tomography (PET).2 In fact, cold-induced glucose uptake was increased by a factor of 15! While the Swedish researchers dipped the subject's foot into an ice bath while in the scanner, another similar study by researchers in the Netherlands chilled their subjects in a 16 degrees Celsius/61 degrees Fahrenheit room for two hours. They too found an uptick in brown fat activity.
Based on animal models, researchers estimate that just 50g of brown fat (which is less than what most study volunteers have been found to have) could burn about 20 percent of your daily caloric intake—and more if 'encouraged.'
According to a previous article on WebMD3:
"Kirsi A. Virtanen, MD, PhD, of the University of Turku, Finland, and colleagues analyzed brown fat in five young men. One of the men had about 2.2 ounces of brown fat. "If the brown [fat] in this example were fully activated, it would burn an amount of energy equivalent to approximately 4.1 kilograms [9 pounds]" of fat over the course of a year, the researchers calculate. And that's a low estimate, as this assumes only 50 percent activation of the brown fat."
Activating Your Brown Fat Might Help to Reduce Your Love Handles
No wonder people are anxious to tap into the fat burning capabilities of brown fat! Interestingly, brown fat actually behaves more like muscle than fat, and as you will soon see, there's good reason for that.
One of the researchers in this area is Bruce Spiegelman, PhD, with Harvard University's Dana-Farber Cancer Institute. Over the past five years, his research team has published at least five studies4 on the topic of brown fat, and in one, they identified a sort of master switch that promotes the production of brown fat. In 2008, they showed that the molecular switch, known as PRDM16, regulates whether immature cells will turn into brown fat or into muscle cells. In an interview with WebMD, Spiegelman said5:
"We showed that brown fat and white fat have completely different origins. Brown fat is derived from muscle. That was a huge surprise."
Another set of researchers from Harvard's Joslin Diabetes Center found another trigger for brown fat—a protein called BMP-7, which also promotes bone growth6. The researchers discovered that this protein acts as a growth factor for brown fat. Mice treated with BMP-7 protein grew up to have more brown fat than untreated mice, and the treated mice also used up more energy.
Needless to say, researchers are excited about the potential for a medical intervention that can help people develop more brown fat. But I would be cautious of any solution in a pill form. Instead, I'd suggest trying out some of the non-invasive methods that have been found to promote brown fat production and its activation. For example, in one mouse study, the animals converted white fat into brown fat simply by exercising.
According to Time Magazine7:
"During exercise, the animals' muscles released a newly discovered enzyme called irisin, which triggered the conversion. It's not clear whether the same phenomenon is true in people, though humans do have the same protein. However, the brown fat that is easily observed in humans tends not to be the kind that is derived from white fat."
Ice Therapy: a Viable Strategy?
Tim Ferriss, author of The Four-Hour Work Week, also published a book called The Four-Hour Body8, which includes the concept of activating your brown fat to boost fat burning by exposing yourself to frigid temperatures. He claims you can increase your fat burning potential by as much as 300 percent simply by adding ice therapy to your dieting strategy. A LiveStrong article backs up Ferriss' claim stating9:
"A NASA scientist told ABC News that's no hyperbole. In studying the effects of temperature on astronauts, he saw people's metabolism boost by 20 percent in environments as mild as 60 degrees. A Joslin researcher told National Public Radio that 3 oz. of brown fat could burn 400 to 500 calories daily."
So, how does Ferriss' Ice Therapy work? Well, by cooling your body down with ice, you're essentially forcing it to burn much more calories by activating your brown fat as the studies above can attest to. His suggestions, from easy to 'hard core,' include the following. Do advance slowly! It may be inadvisable to go straight to the ice bath if you're not used to it!:
- Place an ice pack on your upper back and upper chest for 30 minutes per day (you can do this while relaxing in front of the TV for example)
- Drinking about 500 ml of ice water each morning
- Cold showers
- Immersing yourself in ice water up to your waist for 10 minutes, three times per week. (Simply fill your tub with cold water and ice cubes)
Four More Ways to Boost Your Metabolism
Everyone's metabolism is different, but you can generally speed it up or slow it down within a reasonably short amount of time by making changes to your diet and lifestyle. Aside from resorting to ice therapy, the following common-sense strategies will also help boost your metabolism to encourage weight loss:
- Avoid sugar (particularly fructose) and grains as they are the leading cause of insulin- and leptin-resistance, which directly affect your hunger levels, your fat-burning potential, and consequently your weight
- Listen to your hunger, and eat a healthy meal or snack when hunger calls
- Implement a well-rounded exercise regimen that includes:
- strength training to build muscle (for every pound of muscle that you gain, your body burns 50-70 calories more per day), and
- high-intensity interval training, which has been demonstrated to significantly increase fat loss by boosting human growth hormone production
- Use healthy outlets for stress and negative emotions. Tools like the Emotional Freedom Technique (EFT) are your friend and ally when it comes to losing weight. Meditation, prayer, journaling and even exercise can also provide positive outlets for stress.
Remember, the idea is not to deprive your body or starve yourself into a size 2. The goal is to establish a healthy relationship with food, one that will keep you satisfied, nourished and slim, all at the same time.