How can weight-loss app designers' best engage and support users? A qualitative investigation

Objectives This study explored young adults' experiences of using e-health internetbased computer or mobile phone applications (apps) and what they valued about those apps. Design and methods A qualitative design was used. Semi-structured interviews were conducted with a community sample of 19 young adults who had used a publicly available phone or internet-based application. Transcripts were analysed using thematic analysis. Results Participants valued an attractive user interface. Structure, ease of use, personalised features and accessibility (including dual phone-computer access) were all important to participants and users indicated that continued use depended on these design features. Many believed that a focus on calorie counting was too limiting. Some users mentioned behaviour change strategies and known behaviour change techniques utilised by apps including; self-monitoring, goal setting and behavioural feedback. Only a few users reported positive changes in physical activity levels. Conclusions Use of particular design features and application of evidence-based behaviour change techniques could optimise continued use and the effectiveness of internet/smart phone interventions. Statement of contribution What is already known on this subject? E-health is increasingly used to deliver weight loss/control programs. Most e-health programs have not been founded on evidence-based designs and it is unclear what features and functions users find useful or not so useful. What does this study add? Weight loss app users valued structure, ease of use, personalised features and accessibility. Goal setting and feedback on calorie intake/energy balance were the most widely used behaviour change techniques. Designers should consider an extensive food database, a food scanner, and provision of diaries.