In Defence of Food: An Eater's Manifesto by Michael Pollan

Nutritionism is not the same as nutrition. It is not a scientific subject but an ideology. Ideologies are ways of organizing large areas of life and experience under a set of shared but unexamined assumptions. For nutritionism, the widely shared but unexamined assumption is that the key to understanding food is the nutrient; foods are essentially the sum of their nutrient parts.