For decades, nutrition experts and health authorities have warned of the harms of excessive consumption of saturated fats. Red meat, full-fat dairy and fried foods can raise cholesterol levels, they said, and with them the risk of developing cardiovascular disease.
But Robert F. Kennedy Jr. and other federal health officials in the United States have taken a different position, suggesting that saturated fats have been unfairly demonized and that there is insufficient evidence to prove they are harmful.
Kennedy, the Trump administration’s health secretary, said the next edition of the Dietary Guidelines for Americans, expected in early 2026, “will emphasize the need to consume saturated fats.”
Faced with this potential upheaval of decades-old medical guidelines, we asked nutrition experts for evidence-based advice.
What are saturated fats?
All fatty acids are classified into two main groups according to their molecular structures.
Saturated fats, which tend to be solid at room temperature, are prevalent in animal products like butter, cheese, beef and pork, as well as some oils like coconut oil.
Unsaturated fats are abundant in fish and foods like avocado, nuts, seeds, olive oil and soybean oil. This type of fat tends to have a liquid form at room temperature.
What does the research suggest?
Since the 1950s and 1960s, studies have consistently demonstrated the cardiovascular benefits of limiting saturated fat, says Kevin Klatt, assistant professor of nutritional sciences at the University of Toronto.
Small clinical trials conducted in the 1950s, for example, found that when adults replaced saturated fats (from foods like butter or coconut oil) with unsaturated fats (from sources like sunflower oil or corn oil), their blood cholesterol levels fell. Other studies published around the same time found that those who consumed less saturated fat tended to have lower rates of coronary heart disease than those who consumed more.
Based on this and other research, the American Heart Association in 1961 began recommending that adults at risk for heart disease replace saturated fats with unsaturated fats in their diets. U.S. federal health officials issued similar guidelines for everyone in the first edition of the Dietary Guidelines for Americans in 1980 and recommended limiting saturated fats in later editions.
Studies over the following decades have continued to support this guideline, says Deirdre K. Tobias, an epidemiologist at Brigham and Women’s Hospital in Boston.
In dozens of short-term clinical trials published since 1970, researchers found that the more saturated fat people ate, the higher their blood levels of LDL, the “bad” cholesterol, became. Over time, high LDL can increase your risk of heart attack or stroke.
Long-term trial results, although mixed, have largely shown that the more people reduce the amount of saturated fat they consume, the lower their risk of suffering one of these cardiovascular events.
Why do they want to change the directive on saturated fats?
Public health officials have provided little explanation for why they want to roll back long-standing advice about saturated fats.
Some health influencers, notably those in the MAHA (make America healthy again) movement, have argued that because humans evolved to eat red meat and other animal products high in saturated fat, these foods are inherently good for us.
They claim that seed oils high in unsaturated fats, such as canola oil and soybean oil, which experts recommend as healthier substitutes, have worsened our health. A return to butter and beef tallow, they say, would improve the situation.
But there’s no evidence that seed oils are harmful to your health or that saturated fats are beneficial, says Walter Willett, professor of epidemiology and nutrition at Harvard University’s Chan School of Public Health. In fact, he added, the opposite is true: Eating less saturated fat and more unsaturated fat (including those from seed oils) is likely one of the reasons deaths from cardiovascular disease have declined by about 75 percent since the 1950s, he said.
The idea that eating more saturated fat will make us healthier is “fundamentally false,” says Willett.
There is broad consensus among scientists that replacing saturated fats with unsaturated fats can lower cholesterol levels and the risk of heart disease, says Alice H. Lichtenstein, professor of nutritional science and policy at Tufts University. For this reason, Lichtenstein says guidelines should focus less on limiting saturated fats and more on replacing them with healthier unsaturated fats.
There is also debate among scientists whether all foods containing saturated fats are equally bad. Full-fat dairy products like yogurt and cheese, for example, do not seem systematically linked to harmful health effects, despite their high levels of saturated fat, says Benoît Lamarche, director of the Center for Nutrition, Health and Society at Laval University in Quebec.
Whatever the source, it would be a mistake to start eating more saturated fat, says Klatt. They are not good for your health and add extra calories to your diet.
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