The Public Health Implications of the 2010 Dietary Guidelines

An Expert Interview With David L. Katz, MD, MPH

Janet Kim, MPH


February 15, 2011

In This Article

Dietary Guidance: Too Complex?

Medscape: You appeared to express some frustration with the way in which the guidelines, in general, present their recommendations: different guidance for different populations, and not enough explicit information in conjunction with constructive examples that could have more practical applications for clinical practice and patient counseling. In your opinion, what might account for this complexity?

Dr. Katz: For a long time, we've had the perspective that you need to practice a particular approach to nutrition and diet on the basis of your personal health profile: If you have or are at risk for hypertension, do this; if you have or are at risk for diabetes, do that. Sodium stands out for high blood pressure; sugar and glycemic load stand out for diabetes -- different concerns for different populations; but at the end of the day, you're either healthy or you're not. What I think we failed to consider is that if you have any of these chronic diseases or the risk factors for any of them, you're more at risk for all of the others. People with diabetes are more likely to get heart disease, and they're certainly more likely to have hypertension. People with the inflammation that occurs in tandem with diabetes and heart disease are at increased risk for cancer. Certainly, people with cardiovascular disease are more at risk of having a stroke. It really is a holistic issue: You're either propagating overall health and vitality through diet, or you're not.

Then the other consideration is that everybody in the population is at risk. Sixty-five percent or more of adults in the United States are overweight or obese, and an extremely high and rising proportion of children are also overweight or obese. Diabetes, and even more so insulin resistance, are rampant. We have projections by various researchers and the US Centers for Disease Control and Prevention [CDC] suggesting that by the middle of the 21st century, virtually all adults in the United States will be overweight or obese, and as many as 1 in 3 Americans will have diabetes.[6]

What that means is we're all in the same sinking boat, and so we really can rally around a set of dietary principles that represent optimal eating for just about everybody. People with end-stage liver disease, severe congestive heart failure, severe renal disease, or on dialysis, of course, need a medically prescribed diet, but that's a vanishingly small part of the overall population and not the target of the dietary guidelines.

The more you split the guidance -- here's guidance for you and here's guidance for someone else -- the harder it is to say: Here are the core principles that apply to everybody, and the greater the risk for potential confusion. Sometimes subtlety is good, but clarity is a priority. Too much parsing, and clarity is compromised. I do think we have a good basis to make a recommendation about the theme of healthful eating that's good for just about everybody. That is, it's good for you if you're at risk for diabetes or if you have diabetes; if you are or are at risk for overweight; if you might get or have heart disease; or if you are at risk for or have had cancer. An example that illustrates this nicely is the lifestyle arm of the diabetes prevention program, which was structured for people who did not yet have diabetes, but clearly would have been beneficial for people who already had diabetes as well. This lifestyle intervention, consisting of a balanced healthful diet that would be good for just about anybody, combined with moderate physical activity, reduced the incidence of diabetes in high-risk individuals by 58%, twice as good as the drug metformin. There is clarity and potentially greater uptake if you provide one clear set of universal principles.

Without that, what we really have at the end of the day is a set of guidelines that nobody actually follows, which, by the way, is mostly what the dietary guidelines have historically been. We have to think about what will result in greater uptake. Clarity is certainly one of the elements that could facilitate that, but I also think we need explicit links to resources that might empower clinicians to do more with the dietary guidelines. Maybe that's a core set of principles that they can give out to all of their patients; maybe it's an interactive Website that they can refer patients to (the MyPyramid site has served that purpose); maybe it's systems in supermarkets that make it easy to identify more nutritious food that satisfy the criteria of the dietary guidelines. As of yet, I don't think we've seen anything very explicit in these guidelines that would make the job of the clinician trying to promote better health through better nutrition any easier.


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