This dataset was collected within the Supreme Nudge project, testing the real-world effectiveness of supermarket nudging and pricing strategies on diet quality, food-purchasing behaviour, other food-related behaviours, and cardiometabolic risk markers via a cluster-randomized controlled trial. Twelve Dutch supermarkets were randomized to either being a control supermarket or an intervention supermarket. Regular customers of these supermarkets were recruited as study participants, and individual-level data were collected at baseline, and after three, six and 12 months of follow-up. The original sample across all stores consisted of 412 participants who provided informed consent to participate in the study, and the data in this registry includes data of 354 participants who specifically provided additional informed consent for data sharing beyond the scope of the Supreme Nudge project.