This week, Nature published a study which revealed a newly discovered hormone created from exercise. The hormone — which researchers titled, irisin — is shown to turn white fat cells into brown fat cells. You want brown fat cells! White fat cells are lazy slobs just housing fat. Brown fat cells, on the other hand, are metabolically active and use oxygen and energy to burn calories. Irisin has been shown to achieve this transformation mostly in the deep fat hanging around our organs (think of that belly fat!).

Researchers at the Dana-Farber Cancer Institute and Harvard Medical school studied both mouse and human muscle cells. After both study subjects exercised, scientists looked at PGC1-alpha, a protein muscles produce from exercise. What they discovered is that the protein breaks apart into pieces and one of the pieces produced is the hormone, irisin. Most interesting was that the hormone is the exact same in both mice and people.

While irisin looks to be helpful in lessening susceptibility to obesity, diabetes and other health issues, it does not appear to have an impact on the heart or brain. And, even with the increase of brown fat cells, there was no significant weight loss in both humans and mice. While the hormone may not have activated weight loss, the good new is there was no weight gain. Even even when the subjects ingested a high-fat diet, blood sugar levels remained stable. Irisin certainly did help to maintain the weight.

So, unlike the previous studies revealed in 2011, this one adds a light at the end of the tunnel. Exercise is effective. And eat right and exercise is not such an outdated motto after all.