BackgroundMedical patients are particularly at risk of developing complications during and after hospitalization, due to impaired nutritional intake, physical inactivity, or immobilization. Evaluations of implementation studies on health-promoting interventions for medical patients in hospitals are scarce. The aim of this study was to identify factors affecting the adherence of patients and staff to an integrated physical activity and nutritional intervention on a medical ward.MethodsTwo focus group interviews were conducted: one with patients and another with staff. Three individual telephone interviews were conducted, as three patients were not available at the time of the group interview. An inductive thematic analysis was fundamental to the findings of the study.FindingsNine themes describe factors affecting adherence to integrated physical activity and nutrition intervention. Positive factors described by the patients were new knowledge and insight, and that they felt seen and believed in, which made a significant difference to their motivation. The nursing staff felt that the intervention provided important knowledge related to daily practice, prevented bad consciences due to time issues, and that they experienced happier and more active patients. Both staff and patients found that the approaches of the physiotherapist and the dietician positively changed their behavior, however staff members experienced limited resources as a barrier, and a lack of knowledge seemed to hinder full integration of the intervention. Patients reported that their illness situation, “being on their own,” and failure to negotiate a shared goal with the project staff were barriers to adherence.ConclusionsBoth the nursing staff and patients described positive experiences with the integration of a multifaceted health promotion intervention on physical activity and nutrition, however the nursing staff did not fully participate in the intervention and patient adherence differed; particularly, it tended to diminish when the patients were expected to act on their own.