While the scientific inquiry process is generally linear and highly regimented, every once in awhile, happenstance works its way in. That’s just what happened when researchers at the Mayo Clinic were studying the influence obesity has over cancer treatments and found, instead, that two popular cancer-fighting drugs melted fat off the bodies of morbidly obese mice.

When the researchers gave the rotund rodents the chemotherapy drugs methotrexate and cyclophosphamidem they witnessed dramatic weight loss in the mice – even though they kept their whiskers deep in the grub.

“We were surprised to observe that when morbidly obese mice were treated with certain cancer-fighting drugs, the drugs not only targeted their cancers, but also tended to spontaneously resolve their obesity – even with undiminished gorging on a high-fat diet,” said Mayo Clinic cancer immunotherapist Peter Cohen who co-led the study.

Perhaps most impressively, the drugs seemed to do all the hard work on their own, without affecting the appetites or caloric intake of the mice at all, or causing any toxic effects. The researchers believe that the drugs worked by depleting fat cell precursors in the mice, which means that the rodents simply couldn’t store fat.

“The ease with which this weight loss was achieved in mice – even with continued caloric binging – is in stark contrast to the Herculean difficulties morbidly obese patients experience trying to preserve weight loss through dietary restraint,” said Mayo Clinic immunologist Sandra Gendler, who also participated in the study.

At this point there’s no telling if the fat loss in mice will translate to human candidates, but being that the drugs are already approved for human use – even being employed to fight other conditions like rheumatoid arthritis and psoriasis – further research shouldn’t be too difficult to conduct.