New Study Unlocks Secret of "Hunger Hormone"

For years, scientists have known that a common variation in the FTO gene renders individuals with it far more likely to become obese; however, not until now did they know why.

Published in The Journal of Clinical Investigation, a new study explains how a British-led research team determined that those with the chemical not only had higher levels of ghrelin, the "hunger hormone," but demonstrated higher levels of sensitivity to it in their brains as well.

"It's a double hit," Rachel Batterham from University College London, who led the study, told Reuters.

Specifically, the study examined two groups of men of normal weight, though one featured the high-risk FTO genes while the others did not.

The first tests looked at levels of the hormone both before and after 10 men from each group ate a full meal, determining that levels of the hormone, which makes a person feel hungry, did not fall as far in the high-risk patients after eating. Furthermore, their ghrelin levels began to climb much more quickly than the others.

In addition to this observation, the researchers observed that men with the high-risk gene found images of high-fat foods more appealing than the low-risk men.

"Their brain is set up to be particularly interested in anything to do with high-calorie food," Batterham told BBC News,explaining that they are "biologically programmed to eat more."

Though not involved in the study, Steve Bloom of the Imperial College of London told Reuters that the discovery represents "an important step forward" in unraveling the various factors involved in obesity, which is increasing worldwide and leaves individuals at an increased risk for diabetes, heart disease and some cancers.

According to the World Health Organization, 1.4 billion adults 20 years old and older were considered overweight in 2008. Moreover, in 2011, the UN agency reports that more than 40 million children under the age of five were .