Experts from two of America's leading research facilities have reinforced the necessity for physical exercise to beat obesity, claiming that they have discovered a hormone that is synthesised in response to exercise and can help convert white fat into brown fat to cut the risk of obesity and diabetes, reports the New York Times.

Based on a cellular study involving mice and humans, researchers from Harvard Medical School and the Dana-Farber Cancer Institute have deduced that a hormone called PGC1-alpha might have an important role to play in weight loss treatment. Exercise is the only production source of this hormone, the New York Times learns from the study report.

Lead study author Bruce Spiegelman tells the daily broadsheet newspaper in an interview that PGC1 benefits the health much in the same way as exercise does, explaining that a rise in the levels of muscular PGC1 stimulates the release of a protein molecule known as Fndc5.

The New York Times learns that Fndc5 produces a unique hormone called irisin, among other derivatives. This hormone ventures out of the muscles into the bloodstream before making its way to fat cells where it starts to convert white fat to energy-expending brown fat, adds the daily.

Terming the discovery as "an extraordinary one", Swedish expert in metabolic studies professor Sven Enerback says brown fat burns oxygen and helps stave off extra calories. Obesity treatment might become easier and more effective than before with the discovery, the New York Times says, emphasising that the study proves beyond doubt the merits of exercise on fitness as well as on general well-being.