Can we say what diet is best? Well, not on the Today show.
A study published this week in Circulation: Cardiovascular Quality and Outcomes purportedly compared an array of “popular” diets and found that, despite a whole lot of marketing claims and clamor, none was demonstrably better than another, and none was particularly good.
The study, predictably, has been generating a lot of media attention. This is common to almost all high-profile diet studies and almost always comes to my attention, given the professional lens through which I view the world. This case was different, however. I wrote the editorial that accompanied this article, so I have known about the study in all of its particulars since long before the media embargo lifted. Presumably for that reason, I was asked to opine on the Today show.
As I said on TV, this study does indeed suggest that almost all of the “my diet can beat your diet” claims are a product of salesmanship, not science. Consider the huge number of diet books that have been popular over the yeas, every one of which telling you why it is the best. Obviously, that can't be true about all of them. It isn't even true of any of them.
And if the 576,228 (or so) fad diet books we've had so far have failed to provide the Holy Grail of dietary salvation, what, really, is the likelihood the 576,229th will do so? Let's just go with: not much.
As I noted in my editorial, the new study actually provided only a very narrow window to the never-ending dietary beauty pageant. The researchers compared 3 variations on what they themselves called “carbohydrate restricted” diets: Atkins, South Beach, and the Zone. The fourth contestant was Weight Watchers, which is now more about improving food choices overall, but historically has been about using points as a surrogate for calories.
My assessment of the study, it's strengths, limitations, and implications, is fully developed in the editorial, which the journal has generously made openly accessible here, so I won't revisit all of that. Suffice to say the findings of the research indicated that data and diatribe diverged widely. The data did not really back up the claims and clamor underlying any given diet.
Would this still be true if the window were much wider, examining the full expanse of diets competing for our attention, and our cash?
Yes, it would. I know, because I have been obligated to look through those larger windows. I did so while writing the 3 editions of my nutrition textbook, examining for the newly released third edition, and with the help of my co-authors, nearly 10,000 scientific publications. Yes, it was just as painful as it sounds! But it sure did provide the bird's eye view.
I was obligated to do much the same on a smaller scale to write an invited, peer-reviewed paper entitled, “Can we say what diet is best for health?”
So, can we say what diet is best for health and weight control?
Let's start with a bracing dose of honesty, then come back to that question. If you are reading this, you must be literate. If you are literate, you should be able, despite the crap you learned in high school, to read the writing on the wall. The wall says: Grow up!
Anyone with half a wit knows that a get-rich-quick scheme is almost certain to be a scam. But in our culture, that same, generally sensible person reaches for his or her credit card every time a get-thin-quick scheme comes along.
If that includes you, then: Grow up! There is no magical pixie dust for getting to health, any more than for getting to wealth. Treat the two the same, and acknowledge that time, effort, and commitment are required in both cases. What worthwhile thing in your life happens with no allocation of time or effort? Why should health or weight control be different?
They aren't. Grow up about it.
Now, back to the question: Can we, in fact, say what diet is best, for health, and weight control?
Yes, by looking beyond the beauty pageant. Look, for instance, to the Blue Zones. These populations around the world live longer and better than the rest of us, because of what they have in common. They eat diets of food, not too much, mostly plants; they exercise routinely; they don't smoke; they sleep enough; they are not ridiculously stressed out; and their social connections are strong. Feet, forks, fingers, sleep, stress, and love are the 6 cylinders in the engine of lifestyle as medicine, and they are firing on them all. As a result, they often live to be 100, then go to sleep one night, and just don't wake up. Folks, that's how it's done!
But the Blue Zones are also noteworthy for their diversity. In Loma Linda, Calif., they are vegans. In Costa Rica, their diet includes eggs, dairy, and meat. In Ikaria, Greece and Sardinia, Italy they practice variations on the theme of Mediterranean diets. In Okinawa, Japan, a traditional plant-based, rice-centric diet produces the same outstanding results.
In all cases, the theme is the same: real food, not too much, mostly plants. Or put even more generically: wholesome foods, in sensible combinations. Unlike us here in the U.S., if it glows in the dark by some contrivance other than bioluminescence, they don't eat it!
Why choose low-fat or low-carb, when there are good and bad sources of fat, good and bad sources of carbohydrate? Why choose between low-glycemic and low-salt, when a diet of wholesome foods results reliably in both? Why choose between the quantity of calories and the quality, when the best way to control the former without perennial hunger is to improve the latter? Why choose any dietary dogma at all?
No, looking at the never-ending parade of quick-fix contestants, we cannot say which diet is best, because none is. But looking beyond the beauty pageant, to a vast expanse of evidence and the compelling, real-world examples of the Blue Zones, we certainly can say what theme of eating is best for both health and weight control. Wholesome foods in sensible combinations. No highly processed, willfully addictive, glow-in-the-dark junk. Food, not too much, mostly plants.
I guess for a culture eager for the winner of the swimsuit competition, that theme just isn't sexy enough. But folks, it's the real deal. And there is beauty in it, because a theme leaves wiggle room. A theme means you can choose the variation on the theme that you, and your family, like best. A theme means you can choose your preferred way to love food that loves you back.
Can we say what diet is best? Yes, in fact, we can. But only if we grow up, get real, and look beyond the beauty pageant.
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.