People with brown fat may burn 15% more calories

Unlike white fat, brown fat burns calories through fatty acid oxidation and heat production and is considered a promising target in the fight against the obesity epidemic. The biggest activator of brown fat is moderate cold exposure.

"This data improves our understanding of how brown fat works in humans," said the study's corresponding author, Florian W. Kiefer, M.D., Ph.D., of the Medical University of Vienna in Austria. "We found that individuals with active brown fat burned 20 more kilocalories than those without."

The researchers identified two groups using a PET scan -- those with and without active brown fat. They analyzed brown fat function and energy expenditure in these individuals before and after short-term cold exposure finding that the group with active brown fat not only burned significantly more calories but had a healthier fatty acid blood profile.

"We have to study human brown fat in more detail to see if this organ can protect us against metabolic and cardiovascular disease," Kiefer said.