Obese people are often subject to prejudice and discrimination. Obesity is 70 percent genetic. As researchers at the University of Cambridge (Great Britain) recently discovered, two gene variants in particular increase the risk of obesity. But how can people with a family history of obesity prevent themselves from becoming obese?
One thing is clear: In addition to a balanced diet, sufficient exercise also plays an important role in preventing obesity. The scientists led by Douglas Ruderfer at Vanderbilt University in Nashville (USA) have now examined what “sufficient exercise” actually means in a study published on the specialist portal “Jama Network Open”.
US researchers are studying how much exercise can reduce hereditary obesity risk
To do this, they analyzed the clinical and genetic data of 3,124 test subjects that the US National Institutes of Health had collected for the “All of us” (AoURP) research program.
In the course of this, the AoURP researchers took blood samples from the study participants and examined the DNA of the blood cells at almost 5.5 million locations. They found numerous gene variants that are linked to body mass index. The Vanderbilt researchers combined these gene variants to create a polygenic risk score – that is, an estimate of a person’s genetic susceptibility to a trait or disease.
On average, the study participants were 52.7 years old. They all had a genetic risk of obesity, but were not obese at the start of the study. According to their fitness tracker data, they took an average of 8,326 steps every day over a five-year period.
Within this time frame, 13 percent of subjects who had a low polygenic risk score developed obesity. Among the study participants with a high value, it was 43 percent.
A certain number of extra steps per day can prevent obesity
However, the researchers found that the test subjects were not completely at the mercy of their obesity predisposition. In fact, by increasing physical activity, they can avoid obesity by increasing the number of daily steps they take.
Compared to people with a lower polygenic obesity risk score, people with a high genetic risk of obesity should have a BMI of
22 additional 3460 steps 24 additional 4430 steps 26 additional 5380 steps 28 additional 6350 steps
a day to prevent obesity.
This resulted in the following number of steps:
BMI of 24: 7590 steps per day BMI of 26: 11890 steps per day BMI of 28: 16190 steps per day
“Patients should know that their genetic risk does not determine their entire risk of obesity.”
“I think it’s intuitive that people with a higher genetic risk of obesity need to be more physically active to reduce that risk. But what’s new about this study is that we were able to visualize the amount of exercise required with numbers,” says Evan Brittain, cardiology resident and co-author of the study, in an accompanying Vanderbilt University press release.
Building on the study results, the scientists now want to conduct further research and, among other things, find out whether recommendations for individual activity can promote health and reduce the risk of obesity.
“We would like to test whether knowing your own genetic risk of obesity actually has an influence on behavior,” says Brittain. In his opinion, this knowledge could empower those affected. Current physical activity guidelines would take more of a one-size-fits-all approach. The assistant doctor criticizes this: The guidelines may underestimate the amount of physical activity that is needed to reduce one’s own risk of obesity. Their study results have proven this, not least.
“Most importantly, patients know that their genetic risk does not determine their entire risk of obesity and that they can overcome this risk by getting more exercise,” Brittain said.
Criticism: “Diet and exercise do not change hereditary predisposition”
However, not all scientists share this opinion. “Of course, a healthy diet and exercise always have their place in the treatment of chronic diseases – including obesity,” said doctor Arya Sharma in an interview with FOCUS online. “However, the successes achieved with diet and exercise alone in terms of weight loss are often modest, as they do not change the basic hereditary predisposition or biology of the body,” says the founder of the Canadian Obesity Network.
He advises those affected to consult a doctor and inquire about various treatment options – be it medication or surgery.