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Friday, November 1, 2002

Are Dietary Guidelines a Public Good?

Two federal agencies, the U.S. Department of Agriculture (USDA) and the Department of Health and Human Services (HHS), have published Dietary Guidelines for Americans every five years since 1980. Those guidelines, the latest version of which appeared in 2000, urge Americans to (1) “balance the food you eat with physical activity-maintain or improve your weight,” (2) “choose a diet with plenty of grain products, vegetables, and fruits,” (3) “choose a diet low in fat, saturated fat, and cholesterol,” (4) “eat a variety of foods,” (5) “choose a diet moderate in salt and sodium,” (6) “choose a diet moderate in sugars,” and (7) drink alcohol in moderation, if at all.

At first glance the guidelines, which purport to help Americans to “promote health and prevent disease,” may appear to be a valuable public service, one well worth the cost to taxpayers. On reflection and investigation, however, it is not at all clear that dietary guidelines are a public good, that is, a product better produced by government than by the market. Is it efficient for taxpayers to pay the government to tell them what they should and should not eat? The vanishing budget “surplus” has again made such questions timely and important; the forthcoming Social Security crisis makes such questions crucial.

Like many other government programs, the diet guidelines have proven a miserable failure. The total cost of producing them is hefty. Precise figures for the Guidelines are not readily accessible. Various government agencies annually fund hundreds of studies related to the health effects of human diet. Conservatively, the production of the guidelines costs Americans tens of millions of dollars per year.

On the other side of the equation, the guidelines’ benefits are at best extremely small and at worst negative. By the government’s own measures, the average American is more obese than ever. According to NIH-funded dietary scientist Dr. Barbara Levine, “obesity is an American epidemic.” “Fifty-five percent of us are overweight,” she stated in a public hearing in 2000, “and certainly our children are getting more obese as we speak.”

Ironically, a major contributor to our increased girth may be the government’s guidelines, or more precisely, Americans’ adherence to them. Some government studies indicate that many Americans attempt to follow the guidelines. Interestingly, other government pronouncements presume that Americans’ diets are not “changing in the direction of the Dietary Guidelines’ recommendations” because of “the increasing prevalence of obesity.” (“Q and A’s on Dietary Guidelines for Americans, 2000,” Center for Nutrition Policy and Promotion, June 3, 2000.) Of course such presumptions beg the question. It is not at all clear, after all, that the guidelines accurately reflect the dietary needs of all, or even most, Americans.

Special-interest groups, like the Salt Institute and the Sugar Association, two producer-funded advocacy groups, often cast doubt on the scientific validity of the government’s guidelines. Such groups are by definition biased; obviously, they have incentives to maintain demand for salt and sugar. Biased views, however, are not necessarily entirely wrong. In fact, special interests often provide valid, and much-needed, criticism of scientific assumptions and research methodologies.

Much of the funding for dietary research, after all, ultimately comes from the federal government, which itself is little more than a special interest and a tool for special interests. Why do the government guidelines endorse the consumption of cow’s milk and frown on the consumption of sugar and sodium? One answer may be because dairy producers managed to “capture” the regulatory agencies and to steer them toward the endorsement of milk. Robert Cohen of the Dairy Education Board raised the same point in public hearings prior to the publication of the 2000 Guidelines. “I’d like to ask you, since this is the first time I’ve been asked who funds me, who funds you, Dr. Kennedy? Who funds you, Dr. Watkins and Lurie and Huberto Garza . . .?” (He was addressing Eileen Kennedy, USDA Deputy Undersecretary of Research, Education and Economics; Shirley Watkins of the USDA; Dr. Nicole Lurie of HHS; and Dr. Garza of the USDA.)

Cohen’s answer: dairy producers.

Highly Politicized Process

Indeed, the fact that the guidelines were subjected to public hearings before their publication suggests that the process of producing them is highly politicized. A particularly enlightening instance of the political nature of the process was the suggestion by a fruit-and-vegetable-producers association, the Produce for Better Health Foundation, that the guidelines state that Americans should “enjoy” rather than merely “choose” five to nine daily servings of fruits and vegetables. The Foundation, in effect, was urging the government to tell Americans to eat their spinach and like it too!

The issue of self-interest, however, is even more complex. Deputy Undersecretary Kennedy responded to Cohen’s funding question by stating that “we are funded by the American taxpayer.” That does not mean, however, that the group that composed the guidelines was acting in the best interests of those taxpayers. Governments, and the U.S. government is no exception, tend to attempt to enlarge their powers and influence over time, if only to ensure their continued existence. Since World War I, the U.S. government has been wildly successful at extending its influence, power, and budget. Federal receipts as a percentage of aggregate output, for instance, jumped from its historical level of less than 5 percent to about 20 percent per year, with much of the increase coming during the New Deal and World War II. The government has used its increased receipts to fund all sorts of initiatives, programs, and research that extend the boundaries of its influence all the way into its citizens’ digestive systems.

If this view is correct, the government is more interested in producing dietary guidelines, any guidelines, than in producing “truth.” Like the salt and sugar producers, in other words, the government is acting in its own self-interest and not in the general interest, if such a thing exists. There is little wonder, then, that dietary research methods are deeply flawed and that research findings are often inconclusive, contradictory, or controversial.

Ignoring Diversity

The biggest problem is that the government studies fail to recognize the immense genetic diversity of the American population. The special-interest groups also miss this point, probably because they want to maintain as wide a market for their respective products as possible. The government does admit that “individuals vary in their responses to dietary changes.” However, the government concludes from this fact that “health improvements will be greater for some than others” if its guidelines are followed. Once genetic diversity is admitted, it is not clear why the effects of the government’s guidelines for some, or even for many, may not in fact be negative.

Although the government is acutely aware of the mostly superficial outward manifestations of this genetic diversity-Americans vary widely in hair and skin coloration, for instance-government-sponsored research pays precious little attention to deeper, more fundamental genetic differences. Part of the reason for this may be the controversy surrounding genetic differences in intelligence. Skepticism of claims regarding racial differences in the genetic component of intelligence is well founded. However, other sorts of genetic differences, most of which are probably not rooted in race, should not be dismissed on that account. In other words, if the government were truly interested in creating truth, and not in merely extending its influence, its studies would investigate the possibility that all Americans do not metabolize food in the same way.

The body of anecdotal evidence which suggests that large differences in individual metabolic processes exist is enormous. “Fad diets” actually work, for some people. The government diet also works, but again only for a minority of Americans. Some Americans thrive by eschewing all animal products. Others find the occasional beef, pork, or chicken entrée beneficial. Still others eat little else but meat and cheese and live long, healthy lives.

Evolutionary theory also suggests that individual metabolisms may be markedly different. Nature “selects” those individuals whose characteristics, including their ability to metabolize different types of foods, best match their environments. Americans who trace their distant roots to Arctic climates, for instance, may very well be capable of metabolizing more fat than Americans whose ancestors dwelled for many millennia in areas rich in high-carbohydrate foods like maize, rice, or other grains.

Interestingly, there is little relationship between race and likely ancestral dietary sources, so there is little reason to expect that outward appearances can signal optimal diets. For instance, some areas of Africa are rich in carbohydrate-based foods, while others produce more meats, oils, and nuts. Because humans cannot know the region or diets of their distant ancestors with any degree of certainty, genetic tests appear to be the best means of scientifically determining each individual’s optimal diet. Such tests are not yet available and, of course, it is not at all clear that Americans could not discover their respective optimal diets for themselves. In light of this evidence, a more intellectually honest approach for the government to take would be to encourage Americans to seek the dietary mix that best meets their individual circumstances, not to present cookie-cutter guidelines from on high.

Private Market for Dietary Information

An even better approach would be for the government to leave the production of dietary advice to the private sector and to abandon its dietary research efforts entirely. Human beings survived for millions of years without the aid of government-sponsored dietary research. Why government intervention should suddenly have become necessary in 1980 is not at all clear. Some may contend that the increased consumption of processed foods, many of which are chock full of refined sugars and sodium, made government guidance important. If the government’s guidelines helped to improve Americans’ health, we might agree. But the government’s efforts failed and may even be exacerbating health problems by failing to account for individual genetic differences.

The government’s failure to address the dietary needs of many, if not most, Americans can also be inferred from the fact that a private market for dietary information exists. Each year diet gurus sell millions of copies of books hawking various so-called fad diets. Americans also consume millions of copies of magazines featuring diet-related stories. Like most consumer markets, the dietary-information market offers Americans low-, medium-, and high-quality products. Unlike our paternalistic government, we trust that Americans can decide among the products themselves.

Some may think that an American Institute for Dietary Research might be in order. But that’s unnecessary. If their minds are left unclouded by specious, but authoritative-sounding government guidelines, Americans will be free to discover which diet works best for them. Obesity will probably decrease and health will improve. As an added benefit, a little extra “fat” can be trimmed from the government’s budget.

Robert Wright is author of the newly published Wealth of Nations Rediscovered (Cambridge) and Hamilton Unbound (Greenwood), coauthor of Mutually Beneficial (NYU Press, 2003), and co-editor of History of Corporate Finance and Corporate Governance in Historical Perspective (both Pickering and Chatto, 2003).