The headline looks like a hoax — saturated fat does not cause heart disease — but it’s real. This news is more than just another example of changing health guidelines; it’s a cautionary tale about trusting the scientific consensus.

For more than 50 years, the best scientific minds in America assured us that saturated fat was the enemy. Animal fat, we were instructed, was the chief culprit in causing obesity, Type 2 diabetes and heart disease.