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Forget popular diets. It’s much simpler than that, says nutrition researcher

Eat mostly plants (veggies, fruits, nuts, beans and seeds).
Eat mostly plants: veggies, fruits, nuts, beans and seeds.

“Can we say what diet is best for health?”

That’s the provocative question asked by Dr. David Katz, director of the Yale-Griffin Prevention Research Center, in a long review article published this week in the journal Annual Reviews in Public Health.

In the article, Katz painstakingly compares the scientific evidence for and against popular diets — low-carb, low-fat, low-glycemic, Mediterranean, “mixed, balanced” (such as the DASH diet recommended by the National Institutes of Health), vegan and even Paleolithic (which tries to emulate the dietary pattern of our Stone Age ancestors).

His finding: None of the diets stands out as “best.” And anybody who tells you otherwise is just trying to establish a marketing advantage for their particular diet.

“There have been no rigorous, long-term studies comparing contenders for best diet laurels using methodology that precludes bias and confounding, and for many reasons such studies are unlikely,” Katz writes. “In the absence of such direct comparisons, claims for the established superiority of any one specific diet over others are exaggerated.”

The diets, however, share common elements, or what Katz calls “a more general dietary pattern,” that have proven to be beneficial to human health.

Those elements can be summarized, he adds, in three guiding principles:

  1. Eat minimally processed foods that come directly from nature.
  2. Eat mostly plants (veggies, fruits, nuts, beans and seeds).
  3. When you eat animal foods (meats, eggs and dairy products), make sure they come from animals that were fed mostly on plants.

And, yes, Katz does acknowledge that this advice is very similar to Michael Pollan’s famous saying: “Eat food. Not too much. Mostly plants.”

Universal advice

An important aspect of these three common dietary principles, says Katz, is that they help everybody, no matter what his or her age or health concerns.

“The notion that some combination of foods or nutrients is most important to the prevention and management of diabetes whereas another is most important to cardiovascular disease never made much sense and was very impractical,” he notes. “Given that people with diabetes are at heightened risk of cardiovascular disease, which should they choose?”

Katz also warns about following any guidance “that places an exaggerated emphasis on any one nutrient or food.” Following such advice is “ill advised,” he says.

‘Perpetual confusion and doubt’

If widely adopted, his (and Pollan’s) simple dietary message could have a significant and beneficial impact on the public health, says Katz, perhaps even reversing some of the more troubling medical trends of recent decades, such as the rise in obesity and type 2 diabetes.

“This message, however, is at present a relatively feeble signal lost in a chorus of noise,” he writes. “In pursuit of marketing advantage, notoriety, or some other bias, the defenders of competing diets tend inevitably to emphasize their mutual exclusivities. This pattern conforms well with prevailing media practices, and the result is perpetual confusion and doubt.”

“If as a society we were genuinely interested in consensus about the best dietary pattern, rather than a never-ending parade of beauty pageant contestants, the compatibilities and complementarities of all reasonable candidates for best diet would be fairly evident,” he adds.

Getting there

Of course, there’s also the challenge of getting people to change their eating habits, especially in the midst of that “chorus of noise.”

“The average supermarket in the United States offers in excess of 40,000 products, the majority of which are processed foods in bags, boxes, bottles, jars, and cans — virtually all of which sport marketing messages, many pertaining to health,” writes Katz. “Additional marketing messages populate pages, airwaves, and cyberspace.”

Consumers may need, he adds, the equivalent of a nutritional GPS to “traverse the foodscape and arrive at good health.”

Some such tools are out there, Katz says. He points to the latest Weight Watchers point system, as well as NuVal, a food point-scoring system that he helped develop, as validated examples of approaches that can work.

But it’s going to take a huge effort, Katz acknowledges, to move consumers “there from here.”

“The clutter of competing claims likely obscures the established body of knowledge and forestalls progress, much like the proverbial trees and forest,” he concludes. “We need less debate about what diet is good for health, and much more attention directed at how best to move our cultures/societies in the direction of the well-established theme of optimal eating, for we remain mired a long way from it.”

You can read Katz’s full report — including details about why your favorite dietary approach is not as evidence-based as you may believe — on the Annual Reviews in Public Health’s website.

Comments (4)

  1. Submitted by Todd Hintz on 03/25/2014 - 12:28 pm.


    Eat less and exercise more. Consume more plants and less meat and limit the amount of processed foods you take in.

    People will inevitably complain that it’s not that easy, which is not the point the author and I are trying to make. The solution is indeed easy. Implementing it, however, may not be. We all have busy schedules and competing demands that suck up our time, energy, and attention.

    But look at the other side of the coin. How much time, energy, and attention does heart disease, obesity, and diabetes suck up? Doctor’s visits, the pharmacy, tracking medications, being winded just carrying the laundry up the stairs. All of it eats away at people’s quality of life, not to mention longevity.

    Sure, exercising is hard. But so is being stuck in a wheelchair.

  2. Submitted by Rick Prescott on 03/25/2014 - 04:03 pm.


    I’m not sure that “Eat minimally processed foods” constitutes useful advice unless it’s accompanied by some education.

    Does milk count as processed if it’s pasteurized? How about whole wheat bread? Oatmeal? Eggs? Pasta? Our ideas of where these fall on the spectrum of “processing” may differ greatly. (OK: Don’t eat Twinkies. Check.)

    And just how are you to know what the beef or chicken you eat were fed? Good concept, difficult to put to any real use.

    This advice SOUNDS sensible and practical, but I’m not sure that it is.

    Underlying his conclusions may be the more important principle: Find out as much as you can about the food you eat and make conscious choices. Keep track. Be curious and mindful.

    That may very well be the real advantage of a program like Weight Watchers: It forces you to THINK before you EAT.

    • Submitted by Todd Hintz on 03/26/2014 - 12:46 pm.

      Very Useful

      You can break consumers down into three basic groups:

      -People who haven’t given nutrition a second thought;
      -Those who have some knowledge and are ready to kick their game up a notch;
      -The experts like the author of this article and Michael Polin.

      I get the sense Rick that you’re in the middle category as it sounds like you’ve put some thought into the process and what constitutes good and bad nutrition. Most people though are going to be in the first category. They know they need to eat better, but they’re not sure what ‘better’ means. There’s a cacophony of companies out there who say they have the answer, each with a product or service they want to sell you. It’s no wonder people are confused about which way to go and end up running down a lot of dead ends that leave them worse off than when they started.

      For those people a few truisms such as “eat less processed food” is the right amount of information to get them on the road to eating healthier. Once they’ve got a start, then the pump is primed for more nuanced information such as you’ve suggested.

      The fact that co-ops and organic foods are the fastest growing segments in the supermarket business demonstrates that there are a lot of people following in your footsteps.

  3. Submitted by Presley Martin on 03/26/2014 - 09:38 am.


    Health is wealth. Let’s bring back home economics in school. I know there has been some effort to introduce healthier school lunches, but when they are served on styrofoam and plastic what message are the kids really getting? Our kids should be flying first class in school learning about real healthy simple food and eating off of reusable plates with reusable cutlery.
    A teacher I know made pancakes in class and brought in real maple syrup and the fake corn syrup stuff. None of the kids wanted/or liked the real maple syrup! They all preferred the artificially flavor goo.

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