There are two long term observational studies of diet and health that get more press coverage than all the others combined. New papers on these studies, which say the same things with minor variations, are published every few months in high-impact journals. The editors of these journals don’t seem to mind that the papers they get are unoriginal and the repetitive choice of the same studies amounts to cherry picking, because the authors are the rock stars of the nutritional establishment, and their university, Harvard, has a cachet that guarantees publication, just as an education at Eton guarantees influence in the British political establishment no matter how much of an idiot one happens to be.
Was that too critcal? You be the judge.