The human body has two kinds of fat: the "bad" white kind that stores kilojoules and the "good" brown kind that burns them. Now, researchers say that it is actually possible to make more brown fat to help people lose weight.
"We are now even more optimistic that brown fat could be used for treating obesity and diabetes," said study lead author Dr Aaron Cypess, assistant professor at Harvard Medical School and the Joslin Diabetes Center in Boston.
In 2009, Cypess showed that although adults tend to have a lot more white fat than they do brown, most have some brown fat in an area extending from the front of their neck to their chest.
Now, in a follow-up study Cypess found ore good brown fat cells also exist in deeper fat. In fact, some of them were actually mixed in with white fat cells.
"It's a marbling at the cellular level," Cypess said. "We wondered: Wouldn't it be nice if you could grow more brown fat? The answer is yes."
Fat cells and obesity
The researchers grew mature human brown fat cells from pre-adipocytes, or pre-fat cells, taken from a fresh sample of brown fat. Cypess noted that the process, which took about two weeks in a lab, would probably happen more quickly in the body.
By measuring the oxygen consumption rate of fat cells, the researchers also demonstrated that brown fat does in fact burn a significant number of kilojoules. Although the study concluded that stimulating the growth of additional brown fat may be a promising treatment for obesity, the researchers stressed that making more good fat would not be a substitute for proper diet and exercise.
"As powerful as brown fat could be at burning kilojoules, we can easily out-eat the benefit," Cypess warned.
Because this study was presented at a medical meeting, the findings should be viewed as preliminary until they are published in a peer-reviewed journal.
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