Study: People With Higher Genetic Risk for Obesity May Need More Daily Steps to Manage Weight

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  • For people looking to avoid obesity, the number of daily steps they should take depends on each person’s body mass index and genetic risk of obesity, new research found.

  • Data suggested people with a high obesity risk may need to take more than 11,000 daily steps to lower that added risk.

  • People can increase their daily step count by creating new habits and gradually increasing the distance walked each day, experts said.

How many steps should you take each day to manage your weight? The answer may depend on your risk for obesity, according to new research.

A study published on March 27 in JAMA Network Open found that those with a higher genetic risk of obesity had to log more daily steps than individuals who had a lower genetic propensity for obesity.

“It seems intuitive that the risk of obesity would be related to how much activity one engages in and their genetic background. So I wouldn’t say I was surprised that our findings were consistent with those ideas,” said lead study author Evan Brittain, MD, associate professor of medicine in the Division of Cardiovascular Medicine at Vanderbilt University Medical Center.

“What’s new and exciting is that we were able to estimate the actual amount of activity needed to prevent obesity in a way that accounts for both genetic risk of obesity and one’s current body mass index (BMI),” Brittain told Health.

Here’s what experts had to say about the new research, how a person’s genetic risk for obesity is determined, and how movement can help you manage your weight.

<p>Trinette Reed / Stocksy</p>

Trinette Reed / Stocksy

A Closer Look at the Study’s Findings

The research team behind the study looked at National Institute of Health data from 3,124 people of European ancestry. Participants were, on average, 53 years old, owned a Fitbit fitness tracker, and didn’t have obesity up to 6 months into tracking their activity.

On average, these individuals recorded their physical activity for 5.4 years and walked about 8,326 steps each day.

In addition to this tracker data, researchers calculated participants’ polygenic risk score (PRS)—a measure of genetic risk for a disease, in this case, obesity. Participants were then put in different percentile groups based on that genetic risk.

Over the course of the study, 13% of people in the lowest genetic risk group developed obesity, as compared to 43% of people in the highest risk group.

Brittain and his colleagues found that for each group to have a comparable risk of developing obesity, those with higher polygenic risk scores would need to walk more steps each day. People with a PRS in the 75th percentile would need an extra 2,280 steps per day—for a total of 11,020 steps—to have a risk of obesity similar to those with a PRS in the 50th percentile. Meanwhile, those with a PRS in the 25th percentile could get away with walking just 5,080 steps a day.

Step count recommendations also varied based on a person’s BMI. Those in the 75th PRS percentile who had baseline BMIs of 22, 24, 26, and 28 needed to walk an additional 3,460, 4,430, 5,380, and 6,350 more steps each day, respectively, in order to have a similar obesity risk to their study peers who fell in that 25th percentile.

Though the study was able to provide specific step count recommendations for participants, there are some important caveats when it comes to applying the findings more broadly.

First, 95% of the participants were white and 73% were women. Also, individuals had fitness trackers to monitor their behavior, something that not everyone has access to.

“The population we studied was self-selected in that they chose to purchase and wear a Fitbit device,” Brittain explained. “This population is, on the whole, healthier than the general population. So one might speculate that the step counts we derived for reducing obesity risk were higher than what might be needed for a less healthy population.”

Related: Ask Health: Does Walking 8,000 Steps a Day Have Health Benefits?

Can You Determine Your Genetic Risk for Obesity?

Researchers can calculate PRS for obesity by looking at previous research that tested the influence of genetics on BMI, Brittain explained.

“Each gene gets a ‘weight’ and those weights are averaged for each individual into a ‘genetic risk score,’ or ‘polygenic risk score,’” he said. “In that way, we used the entire genome rather than just genes known to be associated with weight.”

This is important, as there isn’t just one specific gene that can cause obesity, said José Ordovás, PhD, senior scientist and leader of the Nutrition and Genomics Team at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University.

Looking at all of these genes in sum helps paint a picture of someone’s predisposition to gaining weight, he explained.

But Brittain acknowledges that this kind of genetic assessment isn’t necessarily accessible to everyone.

“One’s PRS is not commonly available. But such data are increasingly being returned to patients from commercial sources—like 23andMe,” Brittain added. “So we anticipate a future in which such data may be accessible to both the public and healthcare providers.”

Related: BMI vs. Body Fat Percentage: Which Is a Better Indicator of Health?

The Healthiest Amount of Daily Steps Depend on the Individual

Though everyone may not know their PRS for obesity, the study results hit on a larger point about how the disease is managed in medicine and in society at large.

While public health guidelines encourage people to embrace physical activity to prevent obesity, those blanket recommendations may not be effective for everyone, Ordovás said.

“These findings could lead to more personalized recommendations, where physical activity guidelines take into account a person's genetic susceptibility to obesity,” he told Health.

Essentially, treating and preventing obesity isn’t a monolithic problem—it varies greatly from person to person.

In the future, as genetic testing likely becomes more widely available, Brittain said he sees a future where “doctors will be able to take advantage of this information to provide more personalized ‘prescriptions’ for activity to prevent obesity and other chronic diseases associated with sedentary behavior.”

Related: Study: These Are the Most Effective Ways to Treat Obesity

Increasing Step Count and Other Ways to Prevent Obesity

When looking at these findings, the thought of incorporating 8,000 to 11,000 steps each day might be intimidating for many people, especially for those who aren’t regularly physically active.

That increase would have to be intentional, Brittain said, but could likely be achieved through habitual changes such as taking a walk during phone calls or parking further away from store entrances. But changing your physical activity routine can be difficult and takes time, Ordovás added.

“For someone who isn’t used to walking much during the day, gradually increasing the number of steps is usually more sustainable than making a sudden jump to 10,000 steps,” Ordovás said. “They might start by adding a short walk to their routine and then increasing the distance over time.”

If fitting walks into your schedule isn’t possible, look for other ways to get movement—this could include taking short breaks during work to stretch or walk, or doing high-intensity interval training (HIIT) for a short but effective workout, Ordovás recommended.

Since managing weight is multi-faceted, oftentimes exercise alone isn't enough. Diet coupled with activity can play an important role in managing obesity, especially for those with greater genetic risk, Ordovás said.

“Studies on diet and obesity PRS often find that people with a higher genetic risk for obesity might need to follow stricter dietary guidelines to manage their weight effectively,” he said.

This could mean eating a balanced diet, rich in whole food and low in processed foods, Ordovás added.

Ultimately, Brittain said that this research shows that one’s genetics don’t necessarily mean that personal behavioral changes can’t alter one’s overall health.

“Our data suggest that genetics are not destiny," he said. "The influence of genetics on obesity risk may be mitigated by increasing activity."

Related: 3 Walking Workouts, According to Experts

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