Exposure to cold is the most well-known and well-studied mechanism for switching on energy-burning brown fat.
Humans have three kinds of fat. White adipose tissue, or white fat, comprises the majority of fat in our bodies; its purpose is to store energy for future use. Brown fat is different: Its function is to generate heat to maintain body temperature. Until recently, it was thought that adults did not have brown fat, that it only existed in babies to help them stay warm before they could move around and then essentially vanished. But beginning in 2009, studies have found that many adults have brown fat and that people with more of it tend to be leaner and have lower blood sugar levels. The third kind of fat, beige fat, appears to convert from white to brown when stressed by exposure to cold, and then back to white. This process is encouraging for scientists trying to figure out how to increase brown fat to improve healthy functioning of the body.
“A balanced diet and regular exercise are the cornerstones of healthy metabolism, but sustaining either is difficult for most people. Understanding how brown fat could benefit our health opens up a new direction in obesity research,” says Paul Lee, an endocrinologist at the Garvan Institute of Medical Research in Sydney, where he leads the Brown Fat Physiology Group. “It is not a solution to obesity, but it is an opportunity to explore an alternative strategy for curbing the obesity epidemic.”
When the body senses cold, Lee says, the brain releases norepinephrine, a chemical that essentially ignites the fat-burning process within brown fat. When there is not enough brown fat, the body has to turn to less-efficient heat-generating models, such as shivering.
Aaron Cypess, a clinical investigator at the National Institute of Diabetes and Digestive and Kidney Diseases, calls brown fat the principal organ responsible for generating heat in laboratory animals. “In mice and rats,” Cypess says, “chronic activation of brown fat [by exposing them to low temperatures or to drugs that target brown fat] . . . is associated with a reduction in liver fat, a resistance to diet-induced obesity and improvement in insulin release.”
A 2014 study by Lee — dubbed “the ICEMAN study” — found that after a month of sleeping at cool temperatures, five men increased their stores of brown fat by 30 to 40 percent and metabolized sugars more efficiently after a meal, which could be helpful for people with diabetes. When the sleeping temperature was raised, the brown stores dropped. Cypess says that this research makes it clear that activating or increasing brown fat stores might prevent weight gain, lead to weight loss and provide a new avenue for treating diabetes and obesity.
During the 2 to 3 minutes whole body cryotherapy session, the body is exposed to extreme low temperatures, causing the brain to release norepinephrine and speed up the natural processes in the body. This causes the body to burn 500 to 800 calories per session as well as help to increase brown fat in the body to combat weight gain.
Sadick, Barbara. “How being cold may one day help people lose weight and protect against diabetes.” The Washington Post. 13 August 2017. Web. 4 October 2017.