UC Santa Cruz

Nutritional thinking has undergone several drastic shifts in the past century. Within two decades of the discovery of vitamins in the 1910s, nutrition experts had begun to argue that much of the ill health in the industrial West was caused by the consumption of too many nutritionally impoverished "processed foods"--highly refined cereals, sugars, and fats--and too few vitamin- and mineral-rich "protective foods"--dairy products, eggs, organs, meat, and fresh fruits and vegetables. But between the 1950s and the 1980s, a growing number of nutrition authorities started branding many of these very same foods as artery-clogging killers. The key to avoiding atherosclerosis and other "diseases of civilization," these experts told the public, was to restrict animal fat consumption and eat more carbohydrates. Yet recently, the low-fat, high-carbohydrate message has come under increasing scientific scrutiny. Nutritional thinking, it appears, is poised for another about-face.

Some scholars have come to the conclusion that authoritative dietary advice keeps changing because nutrition science is inherently too uncertain to permit theories about the nature of the ideal diet to be definitively proved or disproved. Others have gone even further and claimed that the nutrient-centered approach to food that has defined the field since its origins over a century ago is at fault. This dissertation challenges these interpretations. It argues that scientific knowledge of the relationship between food and health, in fact, increased in depth and coherence between the 1910s and 1980s, when official dietary advice was going though its seemingly greatest period of flux. During that time, researchers working in a wide range of fields accumulated a vast amount of scientific evidence against the consumption of the highly processed "industrial foods" and in favor of what nutritionists used to call the "protective foods." But this body of evidence failed to cohere into unified perspective, and as a result there were constant shifts in what health authorities considered the ideal diet.