Just because you have one of these genes doesn’t mean you’ll become obese, but in combination with certain behaviors (like eating a lot of fried food or not exercising) you might be more likely to become obese than someone else who has similar habits, but doesn’t carry that gene. While exercise is known to be one of those behaviors you can do to reduce the risk of becoming obese — in people who are genetically predisposed to obesity and those who are not — a new study tells us a little bit more about some of the obesity measures exercise helps prevent in those at higher risk. RELATED: 10 Ways Exercise Boosts Your Health The new data, published today, August 1, 2019, in the journal PLOS Genetics, showed that working out for 30 minutes at least three times a week was associated with a lower incidence of obesity even among people who are genetically predisposed to gain weight. And more specifically, that amount of exercise was linked to a lower body mass index (BMI), less body fat, and slimmer hips in those individuals at higher risk for obesity because of their genes. The new data reinforces what we already know about obesity prevention: Certain behaviors can stop it, says Keith Diaz, PhD, an assistant professor of behavioral medicine at Columbia University Medical Center in New York City, who wasn’t involved in the study. “Your genes are not your destiny,” he says. “The development of obesity ultimately is a combination of both lifestyle and genetics. A healthy lifestyle, including regular exercise, can offset a genetic predisposition to obesity.”
Exercising 3 Days a Week Was Linked to Lower Risk of Obesity
The new study included 18,424 Han Chinese adult participants in the Taiwan Biobank who had genetic tests, or genotyping, to see how many gene variants they have that are associated with obesity and other diseases. Biobank participants also described their exercise habits in structured interviews. More than one-half of the participants said they didn’t exercise regularly. Only about 42 percent of them got 30 minutes of exercise at least three times a week (enough to be considered “regular exercisers” for the sake of the study). Several workouts popular among the regular exercisers — walking, jogging, mountain climbing, and dancing — were associated with a lower BMI among the people with a high genetic risk for obesity. Fo those whose regular exercise was jogging, in addition to having a tendency toward lower BMI, individuals tended to have lower percentages of body fat and a smaller waist and hip circumference compared with everyone in the study who was genetically predisposed to obesity. Other popular workouts, like cycling, swimming, and tai chi, didn’t appear to impact any measures of obesity in people with a high genetic risk. RELATED: 9 Tips to Help You Stick With Your Workout
Data Isn’t Robust Enough to Show Which Exercise Is Best for Thwarting Obesity; It Does Show That Moving on the Regular Helps
But just because this data suggests jogging was the exercise associated with the most benefit in terms of preventing obesity in those predisposed to it, it doesn’t prove that this is the ideal type of exercise, says Wan-Yu Lin, PhD, lead author of the study and an associate professor in the College of Public Health at National Taiwan University in Taipei. And it doesn’t necessarily mean that people who love other sports should abandon them and take up jogging instead. “We do not mean jogging or other slower or steadier aerobic workouts are better for preventing obesity than high intensity interval training or workouts that combine aerobic and strength training,” Dr. Lin says. The data is self-reported by the participants; the researchers didn’t independently nor objectively verify exercise intensity or frequency. There may have been too few people doing some sports to detect a meaningful interaction between these exercises and differences in BMI, body fat, or other obesity measures among people with a genetic predisposition for obesity, Lin says. Only a clinical trial that randomly assigned people of similar genetic risk for obesity to different types of workouts would be able to definitively answer this question. Also, the current study was observational, meaning it took a snapshot of genetic risk and obesity measures to look for connections but wasn’t designed to prove cause and effect. “We cannot rule out the fact that obese adults are likely unable to jog very much but may be able to do other types of exercise,” Dr. Diaz says. “What we could be seeing here is just reflective of the fact that very few obese adults actually jog, rather than jogging preventing obesity.” What the study does contribute to the literature on exercise and obesity is more evidence that moving regularly may influence what’s known as gene expression, a process of switching the activity in DNA on or off that helps to determine whether a certain gene variant will actually lead to obesity. “Two subjects with totally identical genetic makeup may still have different gene expressions,” Lin says. “Exercise may change expressions of ‘fat genes’ and let them become less deleterious to people.” And the study would suggest that jogging is a type of exercise that appears to be good at doing this, even though it’s impossible to know from this study if it’s the best one when it comes to obesity prevention, Diaz adds. Physical activity guidelines from the U.S. Department of Health and Human Services are based on existing data from investigations into the minimum amount of physical activity linked to the most health benefits, in terms of preventing and lowering risk of heart disease, type 2 diabetes, and other diseases, including obesity. They recommend adults should get at least 150 minutes of moderate or vigorous intensity exercise a week, notes the Centers for Disease Control and Prevention. To lose weight, obese adults may need at least 250 minutes a week of exercise, according to previous research by the American College of Sports Medicine. “The exercise should be hard enough that your heart will beat faster and you’ll breathe harder than normal,” Diaz advises. “A simple rule of thumb is that you should be able to talk, but not sing — if you can sing you are not working hard enough.”
