In 2014, TIME Magazine’s cover boldly proclaimed “Eat Butter,” featuring a golden curl of butter against a stark white background. It made butter look like a health hero. “I’m back!” was the tone of the message. The narrative being pushed was that butter was making a comeback, and that it wasn’t the villain it had been portrayed to be. The narrative downplayed the damage that could be done by a diet heavy in saturated fats and suggested that saturated fats really weren’t so bad after all. This message has now been thoroughly adopted on social media. But was this narrative science driven, or was it an oversimplification by the media?
Two key studies—one from 2016 that helped fuel the butter revival and a new 2025 study advocating plant-based oils—reveal starkly different conclusions about butter’s role in our diets. Let’s unpack the science, the differences, and what nutrition experts really say.
The 2016 Study: Butter’s Neutral Stance
The 2016 study, “Is Butter Back? A Systematic Review and Meta-Analysis of Butter Consumption and Risk of Cardiovascular Disease, Diabetes, and Total Mortality,” was published in the journal PLOS ONE. This global study analyzed data from 636,151 participants across 15 global cohorts, mostly from western nations. In this study the researchers found that butter consumption had a weak association with all-cause mortality (a 1% increased risk per 14g/day), no significant link to cardiovascular disease (CVD), and a slight protective effect against type 2 diabetes. The takeaway? Butter appeared relatively neutral—not a health villain, but not a hero either.
Dr. Dariush Mozaffarian, the senior author, contextualized these findings in a 2016 TIME interview: “Vegetable oils and fruits and nuts are healthier than butter, but on the other hand, low-fat turkey meat or a bagel or cornflakes or soda is worse for you than butter.” This layered view highlighted that butter’s impact depends on what it replaces in the diet—a point often lost in the “butter is back” frenzy. The study’s global cohorts and varied adjustments (sometimes including cholesterol levels, which could mask effects) limited its ability to compare butter directly to healthier fats like oils, leaving room for misinterpretation.
“Vegetable oils and fruits and nuts are healthier than butter, but on the other hand, low-fat turkey meat or a bagel or cornflakes or soda is worse for you than butter.” —Dr. Mozaffarian
The 2025 Study: Science Shines the Light on Plant Oils
Now in March, 2025 a new study “Butter and Plant-Based Oils Intake and Mortality” was published in the journal JAMA Internal Medicine. What is coming is a titanic shift in the public’s understanding of the role of butter and oils in our diets. In this study researchers analyzed the diets and lifestyles of 221,054 U.S. health professionals over 33 years. The findings were starkly different from the headlines in 2016. They found that higher butter intake increased total mortality by 15% and cancer mortality by 12% for those in the highest consumption group. (Lower consumption did not increase risk.) In contrast to those eating a lot of butter, people who consumed the most plant-based oils (e.g., olive, canola, soybean) had a 16% lower total mortality risk. And the most striking finding was when they looked at what would happen if you substituted oil in place of butter. Substituting 10g of butter with plant-based oils reduced total mortality and cancer mortality by 17% and CVD mortality by 6%.
Substituting 10g of butter with plant-based oils reduced total mortality and cancer mortality by 17% and CVD mortality by 6%.
What was missing in 2016 was the question “Compared to what?” Butter compared to refined white bread? Butter was no worse. Compared to soda? Butter was better. But that isn’t really the question. Which dietary fat should we be using? That is the question.
This 2025 study’s strong point is in its substitution analysis and detailed dietary data, collected every four years from health-conscious participants. Dr. Walter Willett, a co-author and renowned nutrition researcher, debunked lingering myths in a 2025 CNN interview: “For some reason that is not clear to me, a myth has been floating around the internet that butter is a healthy fat, but there is no good evidence to support this.” Willett’s 40 years of research underscore the consistent evidence favoring unsaturated fats over saturated ones.
Dr. Marion Nestle, Professor Emerita at New York University, echoed this in the same CNN article, noting the study’s observational nature but its alignment with broader evidence: “Even so, it’s consistent with decades of evidence linking saturated fat to health risks and demonstrating quite substantial health benefits of substituting plant oils (including seed oils) for animal fats.” Nestle’s comment grounds the 2025 findings in a long-standing scientific consensus that the 2016 study’s neutrality didn’t completely reflect.
Was “Eat Butter” Ever Supported by Science?
The 2016 and 2025 studies were different in a few very important ways:
Main Question: The 2016 study asked, “Is butter worse than other foods?” The answer was, “No, refined grains and sugar are worse than butter.” The 2025 study asked, “Is butter better than plant oils?” The answer is “No, plant oils are better for all health outcomes.”
Design and Focus: The 2016 meta-analysis pooled diverse global cohorts, examining butter’s effects in isolation or against typical Western diets high in refined carbs. It didn’t emphasize substitution with healthier fats. The 2025 study, a prospective cohort analysis, directly compared butter to plant-based oils, pointing out the latter’s benefits through substitution models.
Cohorts: The 2016 study’s 636,151 participants spanned varied dietary cultures, potentially diluting effects due to inconsistent adjustments. The 2025 study’s 221,054 U.S. health professionals provided precise, repeated dietary data so fewer associations were lost.
Context: The 2016 study emerged during a debate questioning saturated fat’s harms, with dairy fats appearing less harmful than red meat. By 2025, evidence solidified around unsaturated fats’ superiority, as reflected in the substitution findings.
These studies were examining different questions in different contexts. While it appears that the results are in conflict, the truth is more subtle and less straightforward. The earlier study’s findings were misinterpreted by media and butter enthusiasts, while the newer study lines up with dietary guidelines advocating unsaturated fats.
Takeaway: Butter Never Was Back
The “Eat Butter” era, sparked by TIME’s iconic cover, was less a scientific revolution than a media-driven oversimplification. The 2016 study never claimed butter was a health food—it simply found it less harmful than refined carbs or sugary drinks. The 2025 study asked a better question about butter (compared to what?) and it reinforces what nutrition scientists like Mozaffarian, Willett, and Nestle have consistently said for a long time: plant-based oils, rich in unsaturated fats, outperform butter in reducing risk of dying early.
The nutrition message from science has been consistent, despite media’s need for catchy headlines. Butter, in small amounts, is fine—think a pat on your toast or in a recipe. But no one can call it a health food based on what we know now. If you want a long life with less disease, exchange that butter for plant oils that are made with health in mind. You don’t have to eat and cook with refined, bleached, deodorized oils, but you can use expeller-pressed plant oils in salad dressings and in recipes with great benefit. The science is clear, even if the headlines haven’t always been.
