"Our distrust of saturated fat can be traced back to the 1950s, to a man named Ancel Benjamin Keys, a scientist at the University of Minnesota."

"Dr. Keys was formidably persuasive and, through sheer force of will, rose to the top of the nutrition world—even gracing the cover of Time magazine—for relentlessly championing the idea that saturated fats raise cholesterol and, as a result, cause heart attacks.... As the director of the largest nutrition study to date, Dr. Keys was in an excellent position to promote his idea.... Critics have pointed out that Dr. Keys violated several basic scientific norms in his study.... In 1961, Dr. Keys sealed saturated fat's fate by landing a position on the nutrition committee of the American Heart Association, whose dietary guidelines are considered the gold standard.... Too much institutional energy and research money had already been spent trying to prove Dr. Keys's hypothesis. A bias in its favor had grown so strong that the idea just started to seem like common sense...."

Excerpts from The Wall Street Journal piece "The Questionable Link Between Saturated Fat and Heart Disease" (also titled "The Dubious Science Behind Anti-Fat Crusade"). 

Many lessons to be learned here, including: Science ≠ Scientists.