Via Instapundit, salt is apparently not the killer we thought it was, according to Scientific American. I had, within the last year, modified my view of salt=bad to the belief that sodium had a powerful effect on the BP of some people. Perhaps even that is too strong.
There is an assumption, whether derived from a world-made-perfect Christianity or from a more modern Natural Living ethos, that there is some nearly perfect, or at least approximately excellent, diet for the human body. There is an idea that if you eat a,b,c, but not p,q,r, you are well on the road to living to be 80, 90, 100. I have written about this odd idea, and its lack of contact with historical reality before. This fantasy is in sharp contradistinction to both evolutionary and Christian thought, yet advocates of either embrace it happily.
Here's the reality: the human body doesn't have any overall plan to get us through to age 80. It wants to get us through to tomorrow, or at most, through the winter. The machine is approximate, not some finely-tuned secret whose mysteries we must divine. The human body is thrilled to have the main killers removed by our improvements in technology in the last hundred years (refrigeration, antibiotics), and we just keep on living, because of the several redundancies built into our flesh. OTOH, the human machine has no idea how to handle an overabundance of food. There are no checks and balances built into us, because no one had to face this wonderful problem until recently.
Paleo diets, Atkins diets, government-approved diets - these are all approximate, a noticing of what things tend to work to keep us from croaking off too quickly. All the new, great insights into great, over arching theories as to how the body works and how we should eat? They're crap. It's a piecemeal process, and the perfect diet will turn out to be a set of individual discoveries, not an application of a Bible diet, or a macrobiotic diet, or a natural foods insistence.