Food historians have frequently noted the ways in which dietary advice to the public is built on a framework of middle-class values and social norms, even as it references the seemingly neutral language of nutrition science for its authority. As the is-ought problem indicates, the logical gap between the “is” of nutrition science and the “ought” of dietary guidance may be bridged by the a priori values of those with authority to act as nutrition experts. Complicating this picture, science studies scholars have investigated how historical and cultural contexts shape scientific agendas and conclusions, transforming norms and values of those in the position to “do science” into scientific claims of fact. Thus cultural norms around eating, dietary guidance, and findings from nutrition science exist in a complex network of interactions that is, importantly, stratified by those who have a part, directly or indirectly, in shaping the rules for “eating right” and those whose bodies are the target of those rules.
This presentation investigates the moment in history in the U.S. when the definition of a “healthy diet” as presented in national nutrition policy, shifted from indicating a diet that would prevent diseases of nutritional deficiency to one that would prevent chronic disease. This shift, which took place during the 1970s, had significant implications for the type of dietary guidance that was created and the type of evidence used to justify that guidance. For the first time, federal dietary guidance told Americans what foods should be avoided or limited as part of a “healthy diet.” Also for the first time, policymakers relied heavily on the new field of nutritional epidemiology of chronic disease to provide evidence for dietary guidance. Although methods from epidemiology had been useful in generating theories about possible causes of diseases of nutritional deficiencies, hypotheses from those studies could be verified through more rigorous experimental trials.In contrast, nutritional epidemiology studies of chronic disease have no such potential corrective; experimental trials of diseases with complex etiologies and extended latency periods are infeasible in most cases. Since proof of causality can seldom be established experimentally for diet-chronic disease relationships, it is secured discursively, through a web of hypothesized dietary risk factors. At the same time, the “spider” within whose web these factors operate—namely, the social and cultural factors surrounding food, eating practices, and health, including dietary guidance from health experts and the social stratification of health outcomes—remains invisible.
Since the 1970s, its use as the evidentiary foundation of national nutrition policy has legitimized the methods and findings of nutritional epidemiology of chronic disease and reinforced a sense that preventing chronic disease is a simple matter of “eating right,” even as its most influential datasets have followed white, educated, middle-class health professionals deeply invested in cultural norms surrounding food and health. The reproduction of the values and lifestyle preferences of dominant social groups in both nutrition science and dietary policy has had profound implications on narratives of failure and blame surrounding bodies that fail to manifest slenderness and health.