In the last chapter we ended by illustrating the emergence of nutritional discourse by way of the work of scientists, like Wilbur Atwater and others. In a normal history of nutrition the next logical step would be to proceed to the discovery of the other nutrients, for example, vitamins in the early twentieth century. In this book, however, we are more interested in the history of the systems of thought than the history of ideas. For this reason we will return to the eighteenth century to illustrate the following points: first, that Atwater’s scientific interests of the rationalisation of the diet were part of a growing involvement in nutrition taking place at different times and in different spaces; second, that the moral concerns which are explicit in Atwater’s work were not unique to America. Indeed, as we will see, the problem of morality and its expression through food discipline were entrenched in eighteenth-and nineteenth-century thought in which empirical problems of health and economy accompanied transcendental problems of the morals of rationality. Rationality was not just an efficient means of achieving the desired outcomes; it was a moral imperative through which subjects were required to problematise themselves for their own ‘good’. We will therefore examine how a rationalisation of food has been important in setting conditions of possibility which were crucial for the further development of nutrition.