Although I think that's reasonable at some level, I think there's dangers in it as well, in that I don't think we really know that much about metabolism or physiology in the grand scheme of things. Physiological and microbiological studies are plagued by confounds and unreplicability problems, for example, and even where it's not, our understanding is more meager than many think. Trying to tie population-level findings to physiology is great if it's possible, but I don't see it as necessary on either end, at least for awhile.

It wasn't that long ago that the role of microbiome was recognized, for example, and even now it's contentious. Conversely, scores of epidemiological findings have had nice physiological explanations that turned out to be much more complicated, like those involving saturated fat, cholesterol, and carbohydrates. DHA, omega fatty acids, etc. are similar. Physiology is complex enough that you can accommodate just about any finding.

To carry this a bit further, it can be problematic going in the other direction too, from physiology to populations. Some of the anti-sugar advocacy, for example, was rooted in lab studies that neglected the effect of fiber in digestion of fruit, so you had people advocating that whole fruit consumption be avoided based on incomplete understanding. It's hard to argue that unprocessed whole fruit is undesirable on the basis of observational nutrition studies. Someone looking at the wet lab data and advocating abandonment of whole fruits might have done well to look at those observational studies to see why different trends were occurring.

I'm not saying that tying one level to the other at some point isn't necessary. I just think one or the other level can't be dismissed out of hand just because things don't map onto each other initially. It's possible that one level provides clues that the other is missing; it's also possible to come up with plausible but wrong bridges between the two levels.