Preventive Medicine Column

Dr. David L. Katz

US News & World Report is out with their Best Diets 2014 report. I was privileged to serve as one of the judges this year, as I have for the past several years.

USNWR 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.  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 USNWR does a terrific job with this project, 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 tend 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.

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.

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 USNWR 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.

So, take it from one of the judges. 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. 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.




Dr. David L. Katz