The very cornerstone of dietary advice for generations..."
...is being challenged because:
Critics have pointed out that Dr. Keys violated several basic scientific norms in his study.
It's a cautionary tale worth telling no matter the discipline. Studies are often accepted without much challenge because we assume that rigorous controls were in place. But the adage of "Garbage in, garbage out" remains a fundamental truth. I think that is what is relevant and interesting to HN readers.
Even in the context of traditional diets there are good ones and bad ones.
Do you want to look like this guy: http://www.kimmacquarrie.com/wp-content/uploads/2012/07/Mash...
Or this guy: http://1.bp.blogspot.com/-rTRD-USWhSk/UTIwrhmGFcI/AAAAAAAAAT...
They both eat traditional diets, clearly with very different physiological outcomes.