U.S. scientists say they can engineer mice and human cells to produce so-called brown fat, which is a natural energy-burning type of fat that wards off obesity.

The scientists, with the Dana-Farber Cancer Institute in Boston, say they hope to be able to develop the same brown fat for people as a means of fighting obesity and diabetes. Their findings are published in the July 29 edition of the journal Nature.

The researchers identified both parts of what they call a molecular switch that normally causes some immature muscle cells in the embryo to become brown fat cells, scientifically known as brown adipose tissue. The team said in a statement that they have shown other types of cells can be similarly manipulated to produce brown adipose tissue.

The tissue was then transplanted into adult mice that began burning caloric energy at a high rate.

Until recently, scientists have though brown fat was only present in young animals and newborn humans.