A. Trichopoulou and A. Naska, University of Athens 2.1 Introduction Documenting and monitoring dietary patterns are priorities in nutritional epidemiology, in the planning of national food and nutrition policies and in the evaluation of nutrition education strategies. Early efforts in documenting dietary patterns were focused on identifying the specific nutrients that may be responsible for effects on people’s health, but recently research has expanded towards studying patterns of food intake. Food data are often derived from: