Butter may be delicious, but a large new study suggests that the less of it you eat, the longer you may live.

Using more plant-based oils and less butter was associated with a 17% lower risk of dying prematurely and a lower risk of cancer and heart disease, according to a report published Thursday in JAMA Internal Medicine and presented at the American Heart Association EPI/Lifestyle Scientific Sessions.

Researchers at Brigham and Women’s Hospital in Boston analyzed data from more than 200,000 people who were followed for more than three decades. Participants who reported consuming the highest daily amounts of butter were 15% more likely to die prematurely, while people who had a high intake of plant-based oils, especially soybean, canola and olive oil, were 16% less likely to die prematurely, the researchers found.

“The message from this study is: Less butter and more plant-based oil could lead to better health,” said the study’s lead author, Yu Zhang, a graduate student at the Harvard T.H. Chan School of Public Health and a research assistant at Brigham and Women’s Hospital.

“We’re not saying that people should give up butter entirely,” Zhang said. “But we’re suggesting that a small reduction in the daily consumption of butter and an increase in plant-based oil could lead to significant long-term health benefits.”

Zhang couldn’t say exactly how much butter would be OK to consume, but “less would be better.”

The new study looked at data from 221,054 adults who had participated in the Nurses’ Health Study, the Nurses’ Health Study II and the Health Professionals Follow-up Study. At the outset, the average age of people in the Nurses’ Health Study and Health Professionals Follow-up was 56;  it was 36 in the Nurses’ Health Study II.

Every four years, the participants filled out a food frequency questionnaire that included more than 130 items. They were asked how often, on average, they consumed each food item over the past year. The participants had nine possible responses ranging from “never or less than once per month” to “more than six or more times a day.”

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They were also asked what types of fats and oils they consumed and what brands or types of oils they used.

During the 33 years of follow-up, 50,932 of the participants died, 12,241 due to cancer and 11,240 due to heart disease.

After accounting for potentially biasing lifestyle factors, such as body mass index, amount of physical activity, smoking and alcohol consumption, as well as  family history of diabetes, cancer and cardiovascular disease, the researchers determined that people who consumed the highest daily amount of butter (13 to 14 grams, or approximately three small pats) had a 15% greater chance of dying compared to those who consumed the lowest amount (0.1 to 0.2 grams, or almost none).

That’s in contrast to a 16% lower risk of dying in those who consumed the highest amount of plant-based oils (around 25 grams, about five teaspoons a day) compared to those who consumed the least (around 3 grams per day, or 1 teaspoon).

Using a statistical model, the researchers estimated the difference in mortality rate when plant-based oils were substituted for about a teaspoon of butter each day and found a 17% lower risk of death.

When the researchers examined causes of death, they found that each additional 10 grams (roughly 2 teaspoons) per day of plant-based oil was associated with an 11% lower risk of death from cancer and a 6% lower risk of death from cardiovascular diseases.

Dr. Matthew Tomey, a cardiologist at the Mount Sinai Fuster Heart Hospital in New York City, said the new study is consistent with the current American Heart Association guidance regarding substituting polyunsaturated and unsaturated fats for animal and dairy fats.

“The large sample size and robust analysis provide insight, particularly with respect to substitution of plant-based oils for butter,” Tomey said.

The American Heart Association recommends getting less than 6% of total daily calories from saturated fat. For example, if someone is consuming 2,000 calories a day, no more than 120 calories of them should come from saturated fat. That’s about 13 grams or less of saturated fat per day.

Does the new research mean butter should be off the menu?

Marie-Pierre St-Onge, an associate professor of nutritional medicine at the Columbia University Vagelos College of Physicians and Surgeons in New York City, said people should focus on the health benefits of plant-based oils.

“It shouldn’t scare them from using butter,” she said, adding “there’s more benefit to plant-based oil than there is harm from butter.”

The only sign of harm from butter was in people who used it the most, she said.

It comes down to moderation. “Practically speaking, having a pat of butter is not going to be the end of the world,” Tomey said.

It’s OK to have a little butter, if you’re careful about other animal or dairy fats, said Alice H. Lichtenstein, a professor of nutrition science and policy at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University.

“If you’re not consuming a lot of meat and you’re choosing low- or nonfat yogurt, then there’s some room for butter,” Lichtenstein said. “You shouldn’t feel guilty about it.”

The researchers were looking at a group of plant-based products that included soybean and canola oil. How does that factor in with the trend of social influencers trashing seed-based oils?

“I haven’t seen anything in the scientific literature that suggests we should be concerned about these seed-based oils,” St-Onge said.

Lichtenstein concurred. “The data don’t show these oils are detrimental,” she said. “What the data show is that a diet that is high in seed oil and low in animal fats is associated with better health outcomes.”