Scientists gave mice a high fat diet, after which, the mice showed growth of new brain cells and less weight gain.

"We really don't understand the function of these neurons in the normal brain," study researcher Seth Blackshaw, an associate professor at Johns Hopkins University School of Medicine, told LiveScience.

Prof. Blackshaw said the growth of new brain cells has yet to be explained, but initial data makes interesting implications.

"Our data suggests that these neurons may have an important role in regulating feeding."

Researchers noted the new brain cells grew in an area of the brain that seems to regulate eating. They also noted that even after they stopped the new brain-cell growth, the mice on the experiment gained less weight and stayed more active.

The new cells grew in a part of the brain called the median eminence, which lies at the edge of a fluid-filled chamber and therefore outside of the blood-brain barrier (which keeps toxic substances out of the brain), but it extends deep into the hypothalamus, which helps the human body spend the energy it accumulates, reports LiveScience.

The researchers wanted to see how brain cells in the median eminence reacted to a high-fat diet, so they put mice on a "Big Mac" diet - which contained 60 per cent fat instead of the 35 percent fat in regular mouse chow, LiveScience reports.

"We have no idea if this happens in any species other than mice. In humans all the cells and the structures are conserved," Blackshaw said. "I think there's no reason to assume necessarily that this wouldn't happen in humans, but I would be very careful into reading too much in these studies."

The study was published on March 25 in the journal Nature Neuroscience.