Diet and exercise strategies that may lower your ‘biological age’

New Year’s resolutions to eat healthier or exercise more may have an added benefit beyond physical fitness or weight loss: A spate of studies published over the last year suggest that certain diet and exercise regimens might help reduce a person’s “biological age.”

The term refers to indicators of one’s physiological health, rather than how many birthdays they’ve had. Although the measurement can’t predict how long an individual will live, the idea is to assess where someone’s body is in the aging process based on factors like cell damage, organ function or cholesterol and blood pressure levels.

Recent research offers additional evidence that certain habits already known to be healthy — like following a plant-based diet, staying active throughout the day and doing weekly strength training — could stave off some negative health effects associated with aging. 

However, biological aging is a complex process, and experts caution that stress, chronic illness, smoking and a person’s genetics can all complicate the picture. Plus, they said, there are many reasons to get regular exercise and eat a nutrient-rich diet beyond turning back the biological clock.

Nonetheless, here is what five studies published in the last year have found about the links between diet, exercise and aging.

Eat more plants and less junk food

Mounting evidence suggests that plant-based diets may help slow biological aging.

A study published in October looked at the effects of a vegan diet on 22 pairs of identical twins. The researchers assigned one twin in each pair to a vegan meal plan, while the other ate an omnivorous diet that included meat, eggs and dairy, as well as plants. 

At the end of eight weeks, the researchers measured the twins’ biological ages based on their telomeres — protective caps at the ends of chromosomes that shorten with age. Over time, that shortening can prevent cells from dividing, which increases the risk of disease or death. The study also measured changes in the participants’ DNA methylation — a method used by cells to control gene expression — which are strongly correlated with aging. 

The results indicated that the twins who followed the vegan diet showed significant decreases in their biological age relative to the omnivorous group.

Christopher Gardner, one of the study’s authors, said the vegan diets contained more nutrient-rich foods like vegetables, beans and whole grains, as well as less saturated fat. But it’s not clear which aspect of the diet slowed the aging process, he added, or how long the benefits might last.

“It doesn’t mean you can just do this for eight weeks and all of a sudden you’re younger,” said Gardner, a nutrition scientist at Stanford Medicine. 

Plus, not all vegan diets are equally healthy (french fries and soda are technically vegan, after all), so Gardner suggested a simple rule of thumb: Eat more plants and less junk food.

Indeed, a July study found that a higher consumption of antioxidant-rich or anti-inflammatory foods, like vegetables, olive oil, whole grains and seafood, was associated with a younger biological age, whereas a greater sugar intake was associated with an older biological age.

Another study pointed to the benefits of following a calorie-restricted, plant-based regimen just part of the time. Out of a group of 100 adult participants, researchers asked some to follow a strict diet for five consecutive days per month over three months, while eating as they normally would for the rest of the time. On diet days, calorie intake was limited to 700 to 1,100 daily calories, with all food pre-prepared and provided to the participants. The kits contained items like vegetable soup, nut bars and herbal tea. The other study participants simply continued their normal patterns for the full three months. 

The researchers assessed people’s biological ages based on several measures of health, such as cholesterol and blood pressure. They found that the group that had incorporated a plant-based diet into their monthly routines had a biological age that was two-and-a-half years younger than when they started, regardless of whether they lost weight during the study period.

“Every doctor in the United States, this should be part of their toolkit,” said Valter Longo, director of the USC Longevity Institute and one of the study’s authors.

Longo said his research suggests that the special five-day diet he studied may help generate new, healthy cells and reduce insulin resistance, which can in turn lower blood sugar. Such a regimen is likely to make the biggest difference for people who have diabetes, obesity or are overweight, he added.

Daily walks and weekly strength training

Although exercise has long been known to improve brain health, a study published in October found that even a small amount of physical activity could lower one’s “cognitive age” — how young a person are based on their mental acuity. 

The study enrolled more than 200 middle-aged New Yorkers, who were prompted several times per day by a smartphone app to record their physical activity within the last three-and-a-half hours. Immediately after, they were instructed to play “brain games” that measured their cognitive function, such as matching tiles with various symbols. The participants’ speed at solving the games was used as a measure of their brain age.

“We generally get slower as we age cognitively,” said Jonathan Hakun, the study’s author and a neurology professor at Penn State University. “Somewhere in middle age — it’s thought to be somewhere around the sixth or seventh decade — we start to see slightly more rapid change in our ability to solve these problems quickly.”

The study found that people who had recently engaged in physical activity displayed a mental speed associated with a brain age four years younger than they displayed after periods of inactivity. The activity could have been as simple as walking the dog, doing chores or playing with kids. 

Hakun said the findings could result from physical activity arousing the central nervous system.

“The physical activity that we would get in our everyday lives might just put us in a state to be more prepared or ready to respond to a puzzle or problem if it comes up,” he said.

Research this year also found links between a particular type of exercise and a reduction in biological age. A study published in October found that doing 90 minutes of strength training each week — exercises like using weights or resistance to strengthen muscles — was associated with a nearly four-year reduction in biological age. 

The findings were based on 4,800 responses to the National Health and Nutrition Examination Survey, an ongoing study conducted by the Centers for Disease Control and Prevention. Adults who said they engaged in strength training regularly were found to have significantly longer telomeres than adults who did not, suggesting a lower biological age.

Hakun emphasized, though, that the benefits of exercise extend far beyond the cognitive, since regular physical activity is also known to reduce blood sugar and risk factors for heart disease, among many other positive effects.

“People have been regarding physical activity as a large keystone behavior for all dimensions of health,” he said. “I have very rarely come across, if ever, a project that says that physical activity has a negative impact.”