Researchers discovered a new signaling pathway that could help target brown fat so that energy from food is more efficiently burned.

Obesity is on the rise, and it can lead to conditions and medical events such as diabetes, heart attack, and stroke, the University of Bonn reported.

Humans have two types of fat: "bad" white fat cells that form love handles, and "good" brown fat cells that help convert energy into heat.

"If we are able to activate brown fat cells or to convert white fat cells into brown ones, it might be possible to simply melt excess fat away" said Professor Alexander Pfeifer from the Institute of Pharmacology and Toxicology of the University Hospital Bonn.

Researchers found brown fat is activated through adenosine, which is made by the human body. Adenosine is generally released during stress, and requires the adenosine receptor A2A to do its job. 

"If adenosine binds to this receptor in brown fat cells, fat burning is significantly stimulated," said Dr. Thorsten Gnad from Prof. Pfeifer's team.

Previous rodent studies suggested adenosine blocks brown fat, but researchers made the opposite findings when using brown fat cells removed from humans during surgery.These results suggest rats and hamsters do not have the same adenosine signaling pathway reactions as humans.

"The brown fat in mice on the other hand behaves just as in humans," Pfeifer said.

Researchers also looked into whether or not adenosine can transform white fat cells into brown ones in a process known as "browning." White fat lacks an A2A receptor. So it normally cannot burn excess fat through adenosine.

When researchers transferred the A2A receptor gene from brown fat cells to white, they found these cells started browning.

"Through the administration of adenosine-like substances, the mice actually lost weight," Pfeifer said.