Older adults who carry a common variant of the fat mass and obesity gene (FTO) also have a shifted endocrine balance, affecting impulse control and food choices, according to a recent study CBS News reported.

Researchers from Uppsala University in Sweden said found that middle-aged or elderly people with obesity-associated variants of the FTO gene tend to gain more weight as they age. This is because low blood concentrations of the satiety hormone leptin and high blood concentrations of the hunger promoting hormone ghrelin makes carriers of the FTO gene put on weight.

"Sure enough, people who carry one or two copies of the FTO variant show increased intake of high-calorie or fatty food as they age," Dr. Madhav Thambisetty, senior author of the study and chief of clinical and translational neuroscience at the National Institute on Aging's Laboratory of Behavioral Neuroscience, told CBS News.

Thambisetty added that there may be a common biological factor underlying "both the risk for obesity during aging as well as obesity-related behavior like your ability to resist impulse eating."

For the study, researchers from Uppsala University and the University of Umeå collected data from nearly 1,000 elderly participants with an average age of 70 years to examine whether circulating levels of ghrelin and leptin, measured after an overnight fast, are linked to a common variant of FTO.

Researchers found that elderly carrying an obesity-susceptible variant of the FTO gene had plasma ghrelin levels that were approximately 9 percent higher than in non-carriers. In contrast, serum levels of the satiety enhancing hormone leptin were roughly 11 percent lower, researcher Christian Benedict said in a statement.

"The present findings suggest that this FTO variant may facilitate weight gain in humans by shifting the endocrine balance from the satiety hormone leptin toward the hunger promoting hormone ghrelin," Benedict added.

The findings were recently published in the journal Diabetes.