While it has become clear that a system approach is important to improve not only the sustainability of agriculture but also nutrition, the analysis of food systems suffers from overcomplexity. In this context, the aim of the paper was to find ways to reduce the overcomplexity of food systems, using a new system approach which is essential for making our food production and nutrition more sustainable. The method was to structure the sustainability food as a three-dimensional system, by grouping and structuring the scientific approaches existing up to now in the specialized literature, searching and compiling through most of the paper having sustainable food as the main subject. The results were structured by creating a system through a set of four interrelated questions. It argues that the 'how’ of food production and consumption, including the 'how much’, is as important as the question “what” is produced and consumed. The 'who’ dimension is of relevance for the socioeconomic pillar of sustainability, while the 'where’ dimension puts our attention to geographical questions.