A new study suggests that genetics is not destiny when it comes to your odds of becoming obese.
For years, research into “obesity genes” has led many Americans to believe that their DNA makes becoming overweight and obese inevitable.
But the new study shows that daily lifestyle — not genes — probably plays the much bigger role.
The study tracked data on more than 2,500 Americans who were followed for decades — from young adulthood in 1985 to 2010.
Researchers used modern technology to construct a genetic “risk score” for obesity for each participant, based on their individual DNA. They also tracked changes in each person’s body mass index (BMI) over time, to gauge their levels of weight and fitness.
The bottom line, according to lead researcher Dr. VenkateshMurthy, is that “we found fitness is a better predictor than genetics of where your BMI will go over time.”
“Genetics clearly has some influence, but other factors are stronger,” said Murthy, who is an associate professor of internal medicine and radiology at the University of Michigan, in Ann Arbor.
So, your BMI — a measure of weight divided by height — in youth appears to be the best predictor of your long-term obesity risk.
That made sense to one expert in weight management.
“BMI, even at young age, represents both genetics and environment,” noted Dr. Mitchell Roslin, chief of obesity surgery at Lenox Hill Hospital in New York City.
“Many believe that genetic means destiny,” he said, but “no, what is inherited is a susceptibility that is influenced by your behavior.”
The new research supports the notion that “no matter your genetic code, the best method to optimize health is eating well and exercising daily,” said Roslin.
Murthy’s team found that, when considered in combination with a person’s age, sex and history of an overweight parent, BMI in young adulthood explained 52.3% of a person’s BMI 25 years later.
In fact, they believe this combo of environmental factors could explain up to 80% of a person’s BMI variation over time.
In contrast, adding genetics into the mix explained only about 13.6% of BMI 25 years later, Murthy’s group said.
“There’s been a lot of attention to the idea of using genetic information to understand your risk of obesity or being overweight, and for potential drug development to address those genetic risks,” Murthy said in a University of Michigan news release.
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