Indeed the really important question that is slowly being dug in (too slowly in my books) is how a quite strictly testable thing as nutrition science has failed

Indeed the really important question that is slowly being dug in (too slowly in my books) is how a quite strictly testable thing as nutrition science has failed to produce truly actionable results. With at least decently described applicability. Maybe it is because of outside influence, maybe it is due to much to broadly asked question and/or premature generalization. Or following leads without actually testing their veracity, which probably has another cause. Maybe partly ethics preventing us from experimenting on ourselves as a species in a rational way. (Unlike the random uncontrolled irrational experiments we run every second of our life.) Glory, finding or requirement to prescribe action even if we do not know what should be done. Also known as leadership in some circles...