Nutritional epidemiology uses epidemiological methods to examine associations between diet and disease. We use large population studies, mainly the Malmö Diet and Cancer cohort, which was established in the 90s and consists of 28,098 individuals. The diet method used consists of three parts: a) a 7-day food diary b) a 168-item semi-quantitative diet questionnaire c) a 1-hour interview. In the research group, we investigate whether dietary composition influences the risk of developing cardiovascular disease, obesity, type 2 diabetes and cancer, and whether genetic factors influence the observed relationships. Malmo Diet and Cancer have great opportunities to clarify nutrition relationships, as dietary data have high relative validity and biobank makes it possible to take into account genetic differences. Clear information about dietary influence is of great significance for public health because eating habits, in contrast to many other factors, can change during the life cycle.