Scientists turn bad fat into 'good' calorie-burning fat

Scientists have found a way to turn bad fat into calorie burning good fat, and say the discovery could lead to new and better treatments for obesity. White or 'bad' fat typically collects around our waists as well as other parts of the body and stores the extra calories we consume. But brown 'good' fat, found in abundance in babies, acts like a power source, burning calories and generating heat. By the time we are adults, most brown fat has disappeared and been replaced by white fat. Scientists at Johns Hopkins University, Baltimore initially tried to reduce body fat and weight gain in rats by suppressing the production of an appetite-stimulating protein called neuropeptide Y (NPY) in the part of the brain which helps to regulate hunger and thirst. The findings showed that rats treated this way gained less weight after five weeks, compared with untreated rats which became obese, showing that suppressing NPY led to less calories being consumed. However, when the scientists examined the rats with suppressed NPY, they discovered that some of their white fat had been replaced with brown fat. The scientists speculated that white fat tissue may contain some brown fat cells which become activated when NPY is suppressed. In the future, it may be possible to transplant or inject brown fat stem cells under the skin to burn white fat and stimulate weight loss, the researchers said. Dr Sheng Bi, at the university's school of medicine, who led the research said: "If we could get the human body to turn "bad fat" into "good fat" that burns calories instead of storing them, we could add a serious new tool to tackle the obesity epidemic." The findings are published in the journal Cell Metabolism