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Is living clean the key to living long? Maybe not, says a new study by Yeshiva University’s Institute for Aging Research, which shows that people who made it to the ripe age of 95 were just as likely as their shorter-lived peers to engage in the kinds of lifestyle habits that researchers deem unhealthy: eating fried foods, drinking, smoking and failing to exercise.

“They’re as bad as everyone,” says lead researcher Nir Barzilai. “The centenarians were telling us terrible stories about their life habits.”

So if it’s not healthy habits, what’s the secret sauce behind their ageless vim and vigor? It may just be in their remarkable genes, the authors said. “People with exceptional longevity may interact with environmental factors differently than others,” according to the study authors; in other words, those with longevity coded into their DNA may be protected from some of the effects of unhealthy living.

PHOTOS: Centenarians Around the World

How many of us actually have these genes is still unknown. “I know only the people who got there, not the people who may get there,” Barzilai says, noting that the only way to determine whether a person will live a long life is if they actually reach exceptionally old age. “I’m not in the prediction business.”

Barzilai’s team surveyed 477 Ashkenazi Jews between the ages of 95 and 109, with an average age of 97. Participants answered questions about their smoking history, weight, diet and exercise habits at age 70 — the age that was most representative of their typical adulthood lifestyle habits, the scientists said — and their answers were compared to those of 3,164 white individuals aged 65 to 74, collected between 1971 and 1974 for the National Health and Nutrition Examination Survey (NHANES).

This yielded some surprising results:

While 47.8% of long-lived men were overweight or obese, 55% of the comparison group was; as for the women, 43.8% of the long-lived were overweight or obese, while 41.2% of the comparison group was. However, in both men and women, rates of obesity alone were much higher in the comparison group than among the very old

A roughly equal percentage of both groups said they had tried low-fat or low-calorie diets

Only 43% of the long-lived men said they exercised regularly, while 57.2% of the comparison group did; 47% of the centenarian women reported exercising regularly, while 44.1% of the comparison group did

Daily alcohol consumption was similar between the two groups. However, a higher proportion of long-living men than comparison men reported consumption of any alcohol; the opposite was true for women

Almost 30% of the centenarian women had smoked (over 100 cigarettes) in their lifetime, while 26.2% of the comparison women did. Smoking rates were 60% for centenarian men and 75% for comparison men.

“The idea here is that … the [long-lived] have gene variants that are protectant that could trump and negate the bad effects of some bad habits,” says Thomas Perls, associate professor of medicine and geriatrics at Boston University and director of the New England Centenarian Study, who was not involved in the current study.

PHOTOS: See portraits of centenarians

He noted, however, that the findings don’t give us license to slack off on all of our good habits throughout life. For those of us who aren’t fortunate enough to have exceptional longevity genes, lifestyle choices still count.

“It’s very important to understand that it’s not that if you want to live to be 100, you can smoke and not exercise,” Barzilai explains. “It’s that there are rare people who are going to be 100, and for them it doesn’t matter — they get there anyhow.”

There are some limitations to the study, such as the fact that the cohort of Ashkenazi Jews and that of the NHANES sample do not make a perfect comparison. Additionally, there are likely to be other environmental or socioeconomic factors affecting longevity that were beyond the measuring capacity of the scientists. There are also the ever-present inaccuracies associated with self-reporting.

So in case you’re not among the lucky ones with golden long-life genes, you’d probably be wise to hedge your bets. It’s still a smart idea to eat right, move your body regularly, avoid smoking and drink in moderation. That’s advice that will last a lifetime.

MORE: Health Checkup: How to Live 100 Years

Tara Thean is a TIME contributor. Find her on Twitter at @TaraThean. You can also continue the discussion on TIME‘s Facebook page and on Twitter at @TIME.