Scientists have discovered that transplanting brown fat also called 'good fat' could be key to weight loss and it may even prevent diabetes. Scientists at the Joslin Diabetes Center in Boston found that brown fat transplants not only significantly decreased body weight, they also improved insulin sensitivity and glucose metabolism, reducing the risk of diabetes, the 'Daily Mail' reported.

There are two types of fat in the body. One is the much-dreaded white fat, which sits under the skin and gives people a beer belly or wobbly thighs. It's caused by eating too much.

But people also have a smaller amount of brown fat, which generates heat. It does this by boosting the metabolism, by burning large amounts of energy so the body starts to burn up the 'white fat'. When 'switched on' it is said to produce around 300 times more heat than any other organ in the body. Previous research has shown that some people – generally lean ones - have more brown fat than others. This could help explain why they remain a healthy weight without much effort, while others struggle to lose weight.

The new research found that the transplanted brown fat secreted hormones which controlled the body's metabolism. Dr. Laurie Goodyear and colleagues transplanted brown fat from mice of a normal weight into mice which were fed a standard or high-fat diet. Eight to 12 weeks after transplantation, the mice fed a normal diet showed improved glucose tolerance, increased insulin sensitivity, lower body weights and decreased fat mass.

But mice given a 'fake' transplant of glass or beads did not show any improvement, proving the efficacy of brown fat, researchers said. The mice fed a high-fat diet also showed improved glucose metabolism, decreased body weight and a complete reversal of insulin resistance resulting from excess fat consumption.

Researchers now plan to investigate how fat transplants could be used to prevent diabetes. Already, some scientists are investigating ways in which stubborn white fat could be given some of the beneficial characteristics of energy-burning brown fat.

The new study was published in the Journal of Clinical Investigation.