If you’re cuckoo for coconut oil, think again.

That’s the message of a lecture from Dr. Karin Michels of Harvard T.H. Chan School of Public Health, which is currently making the rounds on YouTube. The 50-minute German-language talk, titled “Coconut Oil and Other Nutritional Errors,” debunks the popular belief that the ingredient is a waistline-slimming, brain-boosting superfood.

“Coconut oil is pure poison,” the Harvard professor said, according to a translation by Business Insider. “It is one of the worst foods you can eat.”

This warning could come as a shock to advocates of the thick, fatty stuff, who use it not only for cooking but also blend it into their morning cup of coffee. Enthusiasts say the resulting beverage, called “bulletproof coffee,” curbs hunger and helps beat post-wake-up brain fog.

Some fans even believe that a spoonful of coconut oil can prevent gingivitis and sinusitis, which is why they spend 10 minutes a day gargling with it — a habit known as “oil pulling.”

Michels isn’t the first expert to come out against the oil’s alleged status as a miracle food.

The American Heart Association advised against consuming too much of it in June 2017, after a study found that all saturated fats — regardless of the source — are damaging to heart health.

Just because it comes from a plant doesn’t mean it’s good for you: The same study pointed out that coconut oil, which is 82 percent saturated fat, is actually richer than butter. The saturated fat content of that much-maligned ingredient? Sixty-three percent.