It's ironic that now that a study comes out that supports your view, you accept it, but when the big studies said something opposite people were just "blindly trust the US public health authorities".
The study which had the strongest impact on my opinions with dietary fat consumption was the longitudinal Framingham Heart Study. It's far, far more rigorous (and expensive) than virtually any of the studies being crapped out by the publish or perish grant-chasers. The absolute vitriol and emotional, irrational responses to the contradictions raised by Framingham really taught me lessons about the fashion-driven, corrupt nature of certain communities in academia.