The hypothesis underlying the project ‘BioHealth’ is that food biodiversity in human diets contributes to better health outcomes while simultaneously protecting our ecosystems. Therefore, BioHealth aims to assess how species diversity in diets is associated with cancer risk and mortality in European populations. Biological pathways underlying these associations will also be investigated as well as co-benefits for planetary health. BioHealth will use two complementary cohorts, namely the European Prospective Investigation into Cancer and Nutrition (EPIC) and the NutriNet-Santé study.