Blog | Thursday, February 13, 2014

Judging the judging of diets


US News & World Report is out with their Best Diets 2014 report. Predictably, the release of this annual ranking has involved some degree of fanfare and considerable media attention, and deservedly so. US News has become the go-to authority for imposing the order of rankings on things that matter to us. I have 2 kids recently through college, 1 now in, and 1 on the launch pad, and the US NewsBest Colleges“ site is a routine destination on all Katz household computers. My colleagues and I are quite attentive to the annual release in the fall of the Best Hospitals report.

So it is that the Best Diets report has taken its place in this rarefied company, conjoining to the magazine’s rich legacy of adjudication. In this case, I am an insider, having served as 1 of the judges this year, and the past several years.

US News does an excellent and thorough job of making the evaluation process transparent. There is a link to look over the bios of the expert panel (note: I am on the panel). There is another link to look at the scoring methodology. And then, of course, there are links to the results both overall and by specific category.

Since the results are readily accessible to you, I won’t address them here. That judgment has already been rendered. What I can share here, constructively I hope, is my judgment about judging diets this way in the first place.

I think US News does a terrific job with this project, and the editors who oversee it are highly competent, very efficient, and delightful. The scoring components are very reasonable, reasonably thorough, and fairly applied. The panel of judges they assemble is diverse, multidisciplinary, and very accomplished. As noted, it’s a privilege to be one of their number.

But as you may be suspecting, I do have some concerns. First and foremost, I’m not sure that alternative diets with some salient feature to define them need to compete with one another. As an example of what I mean, my family and I eat mostly plants. Our repertoire of home meals is much oriented toward the Mediterranean, perhaps no surprise given that my wife, who does the cooking, is from that part of the world, having grown up in Southern France. But speaking of oriented, we have no qualms about mixing it up with Asian cuisine, and all enjoy an Asian-style stir-fry with brown rice, a variety of veggies, and either tofu or seafood providing the protein.

A second and related concern is that this kind of exercise may tend to foster a preoccupation with labels, rather than compositional details. What I mean here is that a rank list inclusive of, say, vegetarian diets and separately, low glycemic diets, implies the need to choose between them. But this just isn’t true; a good vegetarian diet, like a good Asian, Mediterranean, or flexitarian diet, will naturally to be low glycemic into the bargain. The attributes of healthful eating tend to cluster, because eating wholesome foods in reasonable combinations convenes them all. A rank list tends to suggest there are either/or choices to be made when there need not be.

That concern is much compounded by the dizzying competition among dietary theories, and labels, at the level of society. As I have addressed in prior columns, we are currently all subject to the best-selling influence of a theory that much of what ails us is the fault of grains, whole or otherwise. This view is completely at odds with the proposition that much of what ails us is due entirely to eating animal flesh and animal products. You can choose between “it’s the meat,” and “it’s the wheat,” and among blame the sugar, blame the salt, blame all fat, blame trans fat, blame saturated fat, blame cholesterol, blame omega-6 fat, blame fructose, blame corn, blame tilapia, blame processing, blame Big Food, blame the government, blame pesticides, or blame your mother.

But again, why choose? If you adhere to Michael Pollan’s both pithy and excellent advice, eat food, not too much, mostly plants, you can have your good fat, good carb, low-glycemic cake, and eat it, too.

There are, I think, certain other liabilities in the process of ranking diets, and probably in the process of ranking anything. Inevitably, to one degree or another, the rich get richer. What I mean by this is that diets with a lot of name recognition have an advantage at the starting line because they are perceived as important. Related to that is the halo effect imparted by an affiliation. So, whereas diets derived from a commercial interest, company, or book may suffer somewhat from an implied pecuniary motive (rightly or wrongly), the DASH diet is clearly a beneficiary of its attachment to the National Institutes of Health. DASH has come in first for the past couple of years not because there is clear evidence it is a “better” diet than many others on the list, but because, in my opinion, it is to some extent riding on the imprimatur of the NIH.

In addition, the application of labels tends to result in lumping when splitting may be in order. At the extreme, that becomes a case where baby and bathwater become indistinguishable. The clearest illustration of that in this year’s rankings is the poor placement of the “Paleo Diet,” which came in last on the overall rank list. On the basis of science, this is not justified. The trouble is, the Paleo Diet labeled is often invoked by people who just like eating meat. There were no hamburgers in the Stone Age; no hot dogs, bacon, or sausage. If the Paleo Diet were defined strictly to mean a diet of game (wild animals) and a diversity of nutrient-dense wild plants, with no processed food and water as the only beverage, it would, on the basis of what we know, and what we can infer, warrant consideration as a legitimate “best diet” contender. When the label is used to justify skipping beans for the sake of baloney, however, it invites a very different conclusion. I have to presume that many of the other judges were sensitive to this tendency, as am I.

Yet another concern about the rankings is the obligation to weigh and measure apples and oranges, if you will, on the same scale. Specifically, programs such as Weight Watchers were compared directly to categories, such as the Mediterranean Diet. But this is something of a nonsensical comparison. The Weight Watchers method could be applied to a Mediterranean (or Asian, or any other) dietary pattern. The process of judging required us to compare this process to that product, rather than allowing for a more pragmatic perspective: This process could be applied to that product.

And finally, from my perspective, some of the most important considerations about diet and health do not figure prominently enough in the US News rankings. I believe that dieting as a go-it-alone-enterprise deserves to die, and should be replaced by a loving-food-that-loves-us-back approach to healthful eating at the level of household, to last a lifetime. Our score sheets offered little opportunity to address the suitability of a given diet for all members of a family. Were that as salient as I think it deserves to be, it would likely reshuffle the deck substantially.

Again, I think US News does a very good job with this challenging proposition. And clearly they are satisfying a want, if not an actual need, at the population level. Rank lists provide clarity and order in an often chaotic world. I suspect we derive comfort from the black-and-white simplicity of them. But simplification and over-simplification are very close cousins, and associating with one may well result in bumping into the other.

So, take it from one of the judges. We had to put mutually exclusive dietary choices into rank order, but you don’t. The elements of eating well are not mutually exclusive and your diet can be somewhat Mediterranean, rather flexitarian, low glycemic, low in added sugar, low in harmful fats, high in volume, less acidic, somewhat Asian, low in bad carbs, rich in plants, somewhat Paleo, sometimes raw and sometimes cooked, all together. You are not obligated to subject your diet to a beauty pageant-like contest. You can eat all plants or mostly plants. You can eat higher or lower fat, protein, or carbohydrate. You can incline toward the Mediterranean, the Asian, or the Stone Age. You don’t need to choose between a program and a dietary pattern; you can apply a program to help you get to the healthful dietary pattern you prefer.

You can prepare your food or have your food delivered, count calories, points, steps, sheep or your blessings, or none of the above. You can both lose weight and find health, and help your loved ones do the same, with any variant you prefer on the theme of healthful eating that conforms to your circumstances and preferences. The best approach to healthful eating is the approach you and your family can actually live with, and learn to love.

So focus on the forest, and don’t let the trees we planted get in your way. From the perspective of this judge, that would show excellent judgment on your part.

David L. Katz, MD, FACP, MPH, FACPM, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care. He is a board certified specialist in both Internal Medicine, and Preventive Medicine/Public Health, and Associate Professor (adjunct) in Public Health Practice at the Yale University School of Medicine. He is the Director and founder (1998) of Yale University's Prevention Research Center; Director and founder of the Integrative Medicine Center at Griffin Hospital (2000) in Derby, Conn.; founder and president of the non-profit Turn the Tide Foundation; and formerly the Director of Medical Studies in Public Health at the Yale School of Medicine for eight years. This post originally appeared on his blog at The Huffington Post.