Research on activation of brown adipose tissue (“brown fat”) by cooling vest for weight loss pointing towards new treatments for obesity and related metabolic diseases.
While surveying exciting new discoveries about cold activated BAT (brown adipose tissue) in humans that have been published recently, an interesting parallel to the Crossfit spawned paleo diet and nutrition plan jumped out at us. If you are not familiar with it, BAT, or brown fat, is now being feverishly studied for its newly discovered role in humans. Use of a cooling vest for weight loss is an exciting natural option for fighting obesity and potentially treating other metabolic disease like diabetes.
In mammals, BAT has long been known to play a critical role in “non-shivering thermogenesis.” What that means is this: brown fat burns glucose to generate heat to maintain core body temperature in mammals when they are exposed to cold. It is “non-shivering” because it is only active before the body gets so cold that major muscles start to contract rapidly to generate heat. By using non-shivering thermogenesis, a mammal can maintain its normal core body temperature efficiently and comfortably. It can adapt to cold conditions long term by turning on this internal furnace and generating heat by burning glucose. That glucose can come by way of stored fat in the form of white adipose tissue (“white fat”). A unique but powerful example is the ability of bears to hibernate. This BAT furnace can supply a slow burn during the winter months fueled by the white fat stored during pre-hibernation gorging.
In humans, scientists believed that BAT did not play any role beyond infancy: our “baby fat” years. However, several years ago it was discovered that BAT showed up on PET scans of some humans. Interestingly, it did not show up in PET scans of overweight and obese humans.
In a way, scientists had a “paleo moment” much like the believers who have championed the paleo diet revolution. If BAT was active in lean to normal weight humans, but not in overweight to obese humans, has our world of controlled environments with central heating and staying indoors played as much a role in the obesity epidemic as fatty diets and overeating? Has our entire natural metabolism gone haywire and short-circuited? Do we need a paleo fitness and lifestyle philosophy to get us outdoors working out in the cold as some have already advocated?
Several studies published in 2009 offered important evidence. In one, obese subjects were subjected to a cool room for a few hours a day. Pre- and post-exposure PET scans showed that subjects who had no visible BAT tissue now showed active BAT. Visible evidence, but more study was needed.
In early 2012, a new study was published that pinpointed BAT activated by cold as being a mechanism behind an eighty percent (80%) increase in Total Energy Expenditure. Yes, that is not a typo, there was an 80% increase in caloric burn caused by non-shivering cold exposure. At Hyperwear, we like to call this phenomenon cool burning or CoolBurn™.
But how are we to take advantage of this BAT boost in caloric burn to fight obesity? Or perhaps more importantly, what is the opportunity to incorporate the benefits of cold activated BAT as part of a healthy lifestyle? Similar to a paleo diet, the idea is to improve health by taking away the artificial ingredients of modern life. Instead of eliminating processed foods and focusing on what foods were natural to the human diet, could we eliminate diet pills, prepackaged and highly processed diet meal plans, and find a way to introduce mild cold exposure into our busy day?
One critical step towards the answer has already been taken. A fascinating and important study done at the Joslin Diabetes Center, Harvard Medical School, published in 2012, compared the effect of mild cold exposure using a cooling vest versus ephedrine (a “diet pill” solution) on BAT activation. At the normal and safe dosage of ephedrine given, the diet pill failed to activate BAT in study subjects, while mild cold exposure did activate BAT and significantly increased energy expenditure. They concluded: “The obesity and diabetes pandemics demand safe and novel treatments, and our findings demonstrate that increasing energy expenditure through BAT is a promising approach.”
What a promising area for more study. General metabolic health benefits seem to be likely too given the role BAT plays and what studies about brown fat health are finding. Studies are underway seeking to see if brown fat can be stimulated to treat obesity and diabetes. At Hyperwear we are intently following this area, investigating a cooling vest for weight loss, and believe it can play a role in an overall program for fitness and wellness. Development of lean body mass is of interest to everyone. And it plays an important role in our life as we are sure the newly re-discovered importance of cold exposure can play in overcoming the controlled environment, sedentary lifestyle of modern life. A “paleo lifestyle” could be the next back to roots movement in fitness. What do you think?
 “In summary, the present study demonstrates that a cold-exposure stimulus designed to minimize muscle-mediated shivering thermogenesis enhances BAT oxidative metabolism as well as glucose and NEFA uptake in adult humans. The enhanced BAT activity was associated with a 1.8-fold increase in whole-body energy expenditure.” Ouellet V., Labbé S. et al. J Clin Invest. 2012;122(2):545–552 doi:10.1172/JCI60433 Adipose tissue oxidative metabolism contributes to energy expenditure during acute cold exposure in humans.
 Cypess A. et al. (2012) PNAS 2012;109:10001 Cold but not sympathomimetics activates human brown adipose tissue in vivo.