It is necessary to develop a more accurate definition of "food system" and then a typology of food systems in order to ensure sound evidence and future policies. The original thinking on food systems implicitly used the industrial model of food supply and distribution, whereas the majority of food consumed in places like sub-Saharan Africa is produced on small farms. In order to compare and analyze the range of food systems found globally, the analytical categories of farming systems have to be merged with food systems thinking and a typology developed that will make it possible to classify the types actually found around the world. Once these systems can be classified they can then be measured and compared according to a variety of variables. The changes going on in the transformation of food systems (often referred to in the literature and discussions) can then be more accurately assessed, and more useful data presented for policy analysis.
Currently, there is much discussion about the "supermarketization" of food systems in areas such as Africa, but less is presented and understood about small farm subsistence food systems as they transition into market food systems and what variables are key to understanding the impacts of different agriculture policies on food access and nutrition for different populations. I believe this question will open up new categories and a classification of food systems that will help illuminate what is happening to populations living and working in different climatic and farming systems, as well as under different conditions of economic develoment, infrastructure and urbanization.