Any reasonable recommendations can only come from large, longitudinal studies, over multiple generations. You know, those that shape the food pyramid / WHO guidelines. And they do exist, and give pretty clear ideas. Such as that halving your meat intake is a good idea.
But I guess that's not exciting, news needs to either repackage (MyPlate) or go after highly fluctuating results from microstudies which is the latest research, but in the stage of formation (all these diet fads, X is bad for you, Y heals cancer, drink a glass of red wine a day [because a encyme in a petri dish did something], etc. ).
By the way, why does there need to be one right way of nutrition? Why can't we accept that multiple ways to obtain the basic building blocks are possible.
In the end, we can't be so off by so much: We have so many people living with such a big variety of foods, and they are doing pretty similarly well (i.e. get older than, and are healthy at, 65). The need to prove that everyones diet is completely wrong is ridiculous.