Abstract Objective: To explore the combined use of quantitative and qualitative methods with a longitudinal perspective in the field of obesity and physical activity Method: A systematic scoping review following PRISMA guidelines. The databases have been Web of Science, PubMed, and ASSIA. Results: 1592 records were returned from the searches. In total, nine studies met the inclusion criteria and were included in the review. The authors mix quantitative and qualitative methods to obtain a deeper understanding of their study subjects, but few documents use longitudinal data. They value the combination of methods and try to integrate the results in their conclusions. Conclusions: Total integration is rarely achieved in the analysis. The origin of this divergence can be found in the lack of theoretical guidance in these articles, but also in the difficulty of working in multidisciplinary teams in the field of obesity.