Coconut oil is under fire again.
The controversial food started gaining popularity in 2011 for its supposed promise of supporting the immune system and helping people lose weight, according to the Chicago Tribune.
Coconut oil has, however, fallen from grace in recent years as some health experts have spoken out against it. Sales of the ingredient reportedly fell in 2017.
In one particularly harsh criticism, Dr. Karin Michels, an adjunct professor at the Harvard T.H. Chan School of Public Health, repeatedly called coconut oil “poison” in a German talk she gave titled “Coconut Oil and Other Nutritional Errors,” USA Today reported.
A video of her speech was posted in July and has been viewed more than 900,000 views on YouTube.
“I can only warn you urgently about coconut oil,” Michels said. “This is one of the worst foods you can eat.”
According to Business Insider, Michels said that coconut oil is more harmful than lard because of its saturated fatty acids, which can clog coronary arteries.
Dr. Frank Sacks, a nutrition professor at the Harvard Chan School, explained the ramifications of consuming saturated fatty acids to The Boston Globe: “Coconut oil is very high in saturated fat, and that raises your LDL cholesterol — bad cholesterol,” he said. “It’s unhealthy to be eating it.”
Several experts agree with Michels’ and Sacks’ assessments.
In The New York Times, Dr. Alice H. Lichtenstein, a Tufts professor of nutrition science and policy, noted that “there’s virtually no data to support the hype” of coconut oil as a healthy ingredient.
Lichtenstein said that “there appears to be no independent benefit of consuming it,” although research about coconut oil’s impact on the body is limited.
CNN reports that a 2016 study found that 72% of Americans — but only 37% of nutritionists — believe that coconut oil is healthy.
Dr. Tom Brenna, a Cornell professor of human nutrition, told The New York Times, “If you’re going to use coconut oil, make sure you get virgin oil … And, of course, everything in moderation.”
This article originally appeared on PEOPLE