Nutrition became a common element of culture, economy and health when the state emerged as a social regulator during the second half of the nineteenth century. A new international landscape was shaped during the inter-war period. Expert knowledge and the science of nutrition became essential as a consequence of the crisis caused by the First World War, international conflicts, and the 1929 stock market crash. The present paper analyses the historical circumstances that made nutrition into a relevant factor for public health policies contributing to its transformation into an experimental science. In this article, the role played by international agencies (the League of Nations, the International Labour Office and the International Institute of Agriculture) and expert committees are considered, as well as the emergence of new scientific and instrumental concepts derived from physiological research, such as optimum diet and dietary standards. Specific cases are considered: rural dietaries in Europe, studies on malnutrition and the critical situation of the population during the Spanish Civil War and on the eve of the Second World War.
