I guess the last few years of news contradicting that fat is bad for you, salt is bad for you and so on had made me believe the legend was long ago punctured.
I would look into Ancel Keys and the diet heart hypothesis.
This idea isn't, and never was grounded in evidence. It's based on very poor science done in the 20th century. The old guard of doctors and health officials will be looked at in the same way we look at geocentrists now. They hold a lot of the blame for the current obesity crisis we have.