Brown fat initially appeared in the science world as an enigma -- a bizarre type of fat that existed in babies, but not all adults, with whole web communities dedicated to the suspicion it caused spontaneous combustion.
While some myths went up in smoke, new Australian research has shown brown fat has an influence on blood sugar levels, opening a new treatment avenue for diabetes.
So what's the difference between the usual white fat and the brown variety? Garvan Institute of Medical Research diabetes and metabolism doctor Paul Lee said white fat stores energy while brown fat burns sugar and fat to create energy.
Yep, it's a fat that burns fat.
Lee and colleague Jerry Greenfield led a team looking at whether brown fat affected blood sugar levels and showed for the first time that those who had more brown fat had less blood sugar fluctuation.
Brown fat is often stored above the collarbones.
"It looks like the more brown fat one has, the more influence it has on blood glucose," Lee said.
“Our findings indicate that brown fat might act as a ‘glucose buffer’, lessening the variation in blood glucose and potentially diminishing metabolic stresses that could increase the risk of diabetes.”
The researchers also made an intriguing observation potentially linking brown fat to sleep -- when study participants woke up, they had a corresponding spike in 'warming brown fat activity'.
“We speculate that this early morning temperature boost may have an evolutionary origin, generating heat and preparing our ancestors for hunting and gathering in the cold as the day begins,” Lee said.
“The study brings brown fat into the frame for developing diabetes therapies. If we can pinpoint what switches brown fats activity on and off during the day, we may identify new targets in drug design."
Brown fat myths busted
Babies have brown fat but adults don't
FALSE: Babies are born with brown fat around their spine and neck, making up about five percent of their body weight and while some adults appear like they have none, it's often hiding in weird places like above the collarbones or the back of the neck.
The colder you are, the more brown fat you have
TRUE: White fat can turn into brown fat in some conditions and a study, also by the Garvan Institute found people who spent 10 hours a day in a climate-controlled building at 19 degrees developed 30-40 percent more brown fat after one month.
Brown fat causes human combustion
FALSE: Because brown fat burns energy to create heat, it was thought this could be the beginning of a chain reaction that ended in someone catching fire from the inside out. There's no conclusive proof spontaneous combustion exists at all, but unconfirmed reports and urban legends abound and some still hold a flame to the idea that brown fat is to blame.
Skinny people have more brown fat
TRUE: Well, sort of. Lean people tend to have more brown fat, but there are exceptions to the rule.