Researchers have identified new genes linked to obesity, which may indicate that some people are genetically predisposed to overeat.
Of the six new genes, five are linked to brain functions, such as appetite control, rather than metabolic functions, such as fat storage or metabolism.
The genes were identified by an international team of researchers, led by scientists at the University of Michigan.
Post-doctoral researcher Cristen Willer, first author of the study, said the findings suggest that those who are overweight or obese may be wired differently than people who more easily maintain a healthy weight.
"It's different if you know that overeating is about biology, and it takes a major effort to overcome that biology," Willer said in a statement. "Clearly, this suggests that some aspects of eating behaviour may be something you're born with."
Researchers compiled their findings by analyzing data from 15 studies that included more than 32,000 people.
The study is published in the journal Nature Genetics.
The findings also suggest that the genes have an effect on people at different stages of their lives.
Three of the genes were linked to a higher incidence rate of obesity among children between the ages of five and 10. However, the three other genes had no effect in the children, and were only associated with obesity in adults.
Co-lead investigator Goncalo Abecasis, an associate professor at the University of Michigan's School of Public Health, said the findings may help scientists develop preventative drug treatments, particularly those that regulate appetite, for people who are pre-disposed to obesity.
"This research tells you a little about what kinds of drugs you want to develop and where you want them to act," Abecasis said in a statement.
In a separate study by Icelandic company deCODE Genetics, researchers identified six of the same genes, in addition to a seventh.
In that study, subjects who carried all of the genes were between 1.5 kilograms and two kilograms heavier than average.
