Is all the fat in our bodies exactly the same?

According to recent research, brown fat is a type of metabolically active lipid that helps the human body burn and use calories. All newborns have this type of fat, which helps them stay warm after leaving the womb.

Scientists have found that adults don't replace all of their brown fat with white fat as they age but keep certain stores of the brown variety that can, as experts hope, be reactivated to stimulate increased metabolism of unused calories. Brown fat is also present at higher levels in healthy people who are not overweight. Researchers have found that it helps the human body cope with cold temperatures (Seda Terzyan, "A Scramble to Harness the Metabolic Power of Brown Fat," Los Angeles Times, Nov. 2, 2009).