Abstract
Leading an unhealthy lifestyle has been associated with physical inactivity and inappropriate diet consumption. Healthy living advice and information can be communicated through mobile health (or mHealth) application technology, and via virtual representations. The literature base investigating the concept and effectiveness of the Digital Twin (an example of a virtual representation) on an mHealth app is yet to be explored. Furthermore, this thesis applied a mixed methods approach, which aimed to address this gap in the literature through a systematic review and three empirical studies. Firstly, a systematic review investigated the potential mechanisms of behaviour change, behaviour change techniques, and digital features that are most frequently used in effective mHealth application and virtual representation interventions (n = 5). Next, Study One (n = 40) applied qualitative designs to investigate the attitudes and perceptions of the Digital Twin. The results highlighted common themes that the experiences and perceptions of the Digital Twin can be conceptualised as initiators and barriers to behaviour change. Study Two (n = 135) applied a quantitative design to assess and evaluate the effectiveness of a novel intervention as a randomised controlled trial in applying a polytheoretical approach. It was found that the Digital Twin (when combined with theory-informed lifestyle messages) was beneficial in promoting healthy lifestyle behaviours. Finally, Study Three (n = 20) applied a qualitative design to explore the users’ experiences of the Digital Twin from Study Two, and if they found it beneficial for managing healthy lifestyle behaviours, and the findings underlined the positive and negative perceptions of the Digital Twin. Overall, this thesis suggests that the Digital Twin may have a significant potential for motivating lifestyle and weight management behaviours alongside theory-informed messages.