Researchers seem to think so! Several studies published in the New England Journal of Medicine show that cold temperature induces activation of brown fat, metabolically active fat deposits in humans, that can help you burn up to 20% of your daily caloric intake.
The importance of brown fat in energy regulation has been demonstrated in animals and new born babies, but it was thought that brown fat does not play a role in adults. Brown fat derives its name from the high number of brown mitochondria found in it. These mitochondria, also known as the powerhouses of the cell, burn a lot of glucose and release its energy as heat, thereby regulating body temperature.
Newborn babies need brown fat to regulate their body temperature. However, as humans age, body takes over thermoregulation and brown fat deposits shrink. Researchers have shown that brown fat is indeed present in the neck and shoulders of adult humans, but its function is still a point of contention. Brown fat was found to be more frequent in women than in men and it was more abundant in lean rather than obese individuals.
Swedish researchers also noticed that brown fat activation occurred in people who immersed their legs into cold water. They stressed, however, that cold water immersion should be done gradually so that the body can get used to the temperature, and one should not be exposed to cold water for too long. So next time, when you want to boost your caloric expenditure, you just might want to have a cold bath or a shower!
However, before you go skinny dipping in ice water keep in mind that over the course of evolution our bodies have gotten really good at maintaining balance, so this increase in caloric burn could also cause a compensatory surge in appetite. Thus, activation of brown fat stores might not necessarily lead to a smaller waist.
Newer research shows that brown fat also may be activated by exercise. In a previous blog post we discussed the connection between brown fat and the fascinating exercise hormone irisin, and this may be part of the bigger picture. But there’s still a lot we don’t know about our metabolism!