Knowing Well, Being Well: well-being born of understanding: Diet Type and Diet Quality, at a Fork in the Road

Nearly 30 years ago, McGinnis and Foege made a seminal contribution to the medical literature with the publication of Actual Causes of Death in the United States. Looking past the proximal, but superficial “causes” routinely listed on death certificates, McGinnis and Foege, honoring the path blazed by Healthy People objectives, asked: what caused these so-called causes? For instance, what caused the accumulation of atherosclerotic plaque that caused the myocardial infarctions that caused the congestive heart failure that culminated in death from cardiogenic shock? That answer, enumerated in a list of 10 factors, was dominated by just three that together explained away some 80% of annual, premature deaths in this country: tobacco, poor diet, and lack of physical activity. These three decades later, that grim trifecta still prevails, but the primacy has shifted. What we do with our feet, forks, and fingers still accounts for some 80% of premature deaths each year, but now forks (ie, our dietary patterns) prevail over fingers (ie, bringing cigarettes to our mouths) as the number one leading cause of premature death in the United States, and much of the world. We have come, in other words, to a fork in the road. That shift in primacy owes something to good news, with declines in the overall rate of smoking. But it owes much to bad news as well: the proliferation of willfully addictive, ultraprocessed junk foods accounting for ever higher percentages of total dietary intake for adults and children alike; the sequential fixation on one nutrient, ingredient, or fad diet in endless parade rather than a stable commitment to eating well for a lifetime. Where that stability does prevail in the world’s Blue Zones, the well documented benefits – a bounty of years in life, a bounty of vital life in those years-are truly luminous. From our vantage here, they are enviable as well. Any number of factors impede our progress toward wholesome foods, mostly plants, in balanced, sensible, and yes-pleasurableassemblies. One among these is the many threads of argument tangling up diet type and diet quality into a common, dogmatic knot with the contention that some particular way of eating is “the best.” Much would be served by muzzling such dogma, and severing that knot. That knot owes something to notoriety. Therapeutic diets tend to derive from an entity with great resources or individual with celebrity and owe their visibility to the light imparted from there. In the treatment of hypertension, for example, thoughts turn immediately to the DASH diet. This is understandable, given that the acronym signifies “dietary approaches to stop hypertension,” and that an entire line of research was devoted to that proposition. But there is also the imprimatur of the NIH conferred upon DASH, thus elevating its stature and familiarity above the many other dietary patterns that might confer as robust an effect, by means of constrained sodium levels and many other shared nutritional characteristics. The same may be said of the dietary pattern plied in the Diabetes Prevention Program. Like DASH, this diet radiates the borrowed light of the NIH. And like DASH, this dietary pattern represents a sanitized version of the prevailing American diet rather than its replacement. Finally, like DASH, the health objective to which this diet was directed may be served by many variants not comparably venerated or even evinced. When our attention does allow for cultural variation in the power of food-as-medicine, we have a clear penchant for favoring the familiar. The therapeutic offerings of theMediterranean diet deserve the respect they receive, but not persuasively at the expense of comparably healthful variants from Japan, India, China, the Caribbean, or Central America. In this, as in all things, the rich get richer: diets studied garner recognition and publication that begets more study. The evidence that accumulates thus for Diet A is meaningful; its absence for Diet B may be far less so. In other words, if the traditional diet of, say, some region in China, Japan, India, or Morocco has all the same benefits as the quintessential Mediterranean diet, or influences blood pressure as favorably as DASHbut simply has not been studied in ways that allow for expression of such effects in the peer-reviewed literature-we have an absence of evidence, not any evidence of absent benefit. The benefit is there, waiting to be found; we have not looked.