Popularized by Michael Pollan in his best-selling In Defense of Food, Gyorgy Scrinis' concept of nutritionism refers to the reductive understanding of nutrients as the key indicators of healthy food -- an approach to food that now dominates nutrition science, dietary advice, and food marketing. Scrinis argues that this ideology of nutritionism has narrowed and in some cases distorted our appreciation of food quality, such that even highly processed foods may be perceived as healthful depending on their content of "good" or "bad" nutrients. Through an engaging investigation into such issues as the butter versus margarine debate, the battle between low-fat, low-carb, and other weight-loss diets, and the food industry's strategic promotion of nutritionally enhanced foods, Scrinis builds a revealing history of the scientific, social, and economic factors driving our modern fascination with nutrition. Scrinis identifies the historical phases that gave rise to nutritionism: the era of quantification, in which the idea of protective nutrients, caloric reductionism, and vitamins' curative effects took shape; the era of good and bad nutritionism, which set nutricentric guidelines and defined the parameters of unhealthy nutrients; and the era of functional nutritionism, in which the focus has shifted to targeted nutrients, superfoods, and optimal diets. His research underscores the critical role of nutrition science and dietary advice in shaping personal subjectivity and embodiment, and in heightening our nutritional anxieties. He ultimately shows how nutritionism has come to align the demands and perceived needs of consumers with the commercial interests of food manufacturers and corporations. His study concludes with an alternative paradigm for assessing the healthfulness of foods -- the food quality paradigm -- that privileges food production and processing quality, cultural-traditional knowledge, and sensual-practical experience, and promotes non-reductive forms of nutrition research and dietary advice.