Development of a theory and evidence-based, user-centred family healthy eating app

The proliferation of health promotion apps along with smartphone's array of features supporting health behaviour change, offers a new and innovative approach to childhood weight management. However, research on the content of current industry led apps reveals they lack a basis in behaviour change theory and evidence. Equally important remains the issue of how to maximise users' engagement with mHealth. Therefore the thesis aimed to address these gaps and design and develop an evidence and theory based, user-centred healthy eating app targeting parents for childhood weight management. The Behaviour Change Wheel framework (BCW), a theoretically-based approach for health behaviour change intervention development, along with a user-centred design philosophy and collaboration with industry, guided the development process. This involved a review of the evidence and conducting a series of nine focus groups (Study one and two), a usability workshop and a 'Think Aloud' study (study three) (N=70) comprised of Change4Life advisors, parents with overweight and healthy weight children aged 5-11 years, university students and staff and consultation with experts to inform the app development. Thematic analysis of focus groups helped to extract information related to relevant theoretical (using the Capability, Opportunity, Motivation, Behaviour Model (COM-B) and Theoretical Domains Framework (TDF)), user-centred and technological components to underpin the design and development of the app. Inputs from parents, case workers and experts working in the area of childhood weight management helped to identify the main target behaviour: to support parents' provision of age appropriate food portion sizes. To achieve this target behaviour, the behavioural analysis revealed the need for eliciting change in parents' Capability, Motivation and Opportunity and twelve associated TDF domains. Therefore, the thesis provides a more comprehensive analysis of the problem compared to previous theoretical accounts, demonstrating that parents' internal processes such as their emotional responses, habits and beliefs, along with social influences such as partners and grandparents and the environmental influences relating to aspects such as schools, the media, and household objects, all interact and impact on their portion behaviours. Theoretical domains were subsequently mapped to five intervention functions and twenty-three behaviour change techniques (BCTs) to bring about change in this target behaviour. BCTs were then translated into engaging app features drawing on parental preferences for healthy eating app features including ease of use, minimal data input, visual aids of food and gamification. Overall parents viewed the prototype app positively. The 'Think Aloud' study highlighted key areas to improve usability in such as navigability. Application of the BCW to the issue of childhood weight management yielded a novel conceptualisation of potential approaches to supporting parents' portion behaviours in the home environment. This thesis is also the first to fully explicate the systematic approach applied in developing a family-oriented mHealth app grounded in the BCW framework and evidence, and balanced with users' preferences to help maximise its potential engagement with the target population. Challenges and adaptations relating to the implementation of the BCW are discussed and suggestions for future research in mHealth development and childhood weight management are provided, along with the implications for public health practice.