Researchers at the Edinburgh University identified the protein, known as 11BetaHSD1, which plays a part in how and where fat is stored in the body -- around the hips or on the tummy.

The findings, the researchers said, shed light on how the protein works, which could help development of medicines to treat obesity, the Daily Mail reported.

Levels of 11BetaHSD1 are higher when an unhealthy type of body fat is stored around the torso. This is typical of overweight people whose "apple-shaped" bodies put them at greater risk of heart disease, the researchers said.

But lower levels of the protein are found when healthier fat is stored around the hips -- typical of "pear-shaped" people -- and used more safely as a source of energy, they said.
According to scientists, fat packed around the organs in the abdomen is more dangerous than fat on the hips because it's "metabolically active", releasing more of the acids that raise heart disease risk, along with factors that increase blood pressure and blood sugar.

Dr Nik Morton, of the University of Edinburgh's Centre for Cardiovascular Science, said: "This study opens up new avenues for research, and gives us a much better idea of why some fat in the body becomes unhealthy while other fat is safely stored for energy.

"Inflammation in of the unhealthy fat leads to reactions that can cause harm locally to tissues and affect the whole organism, promoting diabetes."

In their study, the researchers looked at the effect of the protein in mice put on a high fat diet for four weeks.

They found that those with the protein in their bodies were more likely to have unhealthy fat tissue on a high fat diet, compared with mice without the protein.

Scientists are already looking at ways to make medicines that inhibit this protein, which is known to raise levels of hormones linked to obesity.

"Limiting the presence of this protein could help combat this," said Dr Morton.
As well as being more likely to be stored around vital organs in the torso, fat with higher levels of 11BetaHSD1 is considered to be unhealthy as it is associated with an over-reaction in the immune system, he added.

Cells normally become inflamed in order to kill off an infection, but as there is no infection in the fat tissue the inflammation instead causes damage to healthy cells.

The new research, which was funded by the Wellcome Trust and British Heart Foundation, was published in the journal Diabetes.