Patients with mesothelioma (PwM) have a poor prognosis and are at risk of adverse health outcomes and poor health-related quality of life. Sarcopenia and malnutrition are important prognostic factors for cancer patients and can be partially reversed with adequate nutrition and physical activity/exercise. There is a limited evidence base about the nutritional status of PwM, the understanding of which might potentially influence interventions in PwM. The primary aim of the Help-Meso (Health and Lifestyle of PwM) study is to describe the nutrition, appetite, physical activity and attitude towards lifestyle interventions of PwM. Patients, informal carers and health professionals will be invited to participate in semi-structured interviews and thematic analysis will be performed. The secondary aim of Help-Meso is to assess the feasibility of nutritional screening of PwM via a validated quantitative tool (Malnutrition Universal Screening Tool). The findings from this study will provide an understanding of the health and lifestyle of PwM and the corresponding attitudes of their informal carers and healthcare providers. This information will inform the design of future targeted interventions to improve the nutrition, quality of life of PwM and outcomes. The study has Research Ethics Committee (REC) and Health Research Authority approvals obtained from Wales REC7 (Integrated Research Application System (IRAS) project ID 287193).