New research offers more evidence that genes play a significant role in obesity.
The findings may help explain why some people are more likely to put on extra pounds and develop obesity-linked conditions, the investigators said.
The researchers analyzed genetic samples from more than 300,000 people and identified more than 140 locations across their sets of DNA that play a role in obesity. They also pinpointed new biological pathways that play important roles in body weight and fat distribution.
The findings appear in two companion papers published Feb. 11 in the journal Nature.
This is the first step toward identifying individual genes involved in body shape and size, the researchers said. The proteins produced by the genes could offer targets for the development of new drugs to fight obesity.
One of the papers focused on genes that affect where fat is stored in the body, which affects health risk. For example, people with more belly fat are more likely to have metabolic conditions such as type 2 diabetes and cardiovascular disease than those with more fat in the hips or distributed throughout the body.
"We need to know these genetic locations because different fat deposits pose different health risks," senior author Karen Mohlke, a professor of genetics at the University of North Carolina School of Medicine, said in a University of Michigan Health System news release.
"If we can figure out which genes influence where fat is deposited, it could help us understand the biology that leads to various health conditions, such as insulin resistance/diabetes, metabolic syndrome and heart disease," she explained.
The other paper looked at the link between genes and body mass index (BMI), an estimate of body fat based on height and weight. The researchers said they found 97 genetic associations linked to BMI. They also found that genetic locations associated with BMI are linked to areas that control factors such as appetite and energy use.
"Our work clearly shows that predisposition to obesity and increased BMI is not due to a single gene or genetic change," Dr. Elizabeth Speliotes, senior author of the BMI paper, said in the news release. She is an assistant professor of internal medicine and of computational medicine and bioinformatics at the University of Michigan Health System.
"The large number of genes makes it less likely that one solution to beat obesity will work for everyone, and opens the door to possible ways we could use genetic clues to help defeat obesity," she added.
The next step, the researchers said, is to figure out exactly how these genes function and how they make people more susceptible to obesity.