Genes that predispose people to obesity act in the brain, suggesting that perhaps some people are simply hardwired to overeat, research finds. An international research team co-led by U-M found six new genes that help explain body mass index and obesity, and all but one of the genes are tied to the brain rather than to metabolic functions, such as fat storage and sugar metabolism.
In addition to the six new genes, the study also confirmed the role of two others previously associated with obesity, says co-principal investigator Goncalo Abecasis, an associate professor at the School of Public Health who helped direct and write the paper.
It’s significant that five of the six new genes also impact brain function because the findings suggest people simply could be programmed to overeat, says Cristen Willer, a postdoctoral researcher and first author on the paper. The brain, she says, has two main functions related to weight: appetite control and the regulation of one’s total energy balance (whether you burn more calories or conserve more energy).
“This research tells you a little about what kinds of drugs you want to develop and where you want them to act,” Abecasis says.
Unfortunately society often is unforgiving of overweight people, assuming them weak or lacking in discipline. “If you just want to think about how you react to these people who are obese, they can just be wired differently, so you have to be respectful of that,” Abecasis says.
“It’s different if you know that overeating is about biology, and it takes a major effort to overcome that biology,” Willer says. “Clearly this suggests that some aspects of eating behavior may be something you’re born with.”
For example one of the genes, NEGR1, controls how your brain is wired as it’s developing by regulating neuronal growth, Abecasis says.
“In younger children ages 5-10 we found that with three of (the genes) the children were already heavier at that young age, and with the other three genes, we saw that there was no effect on children,” Abecasis says. “For those, we only saw an effect in much older individuals. This points to different mechanisms influencing your weight at different ages.”
The study appears online in advance of print publication in the journal Nature Genetics.
