Novel multi-method approach investigating behaviour change maintenance

Abstract

Background: Behaviour change, if maintained, can lead to significant health improvements. The aim of this thesis was to advance psychological theory of behaviour change maintenance and the design of behavioural interventions to improve health. This thesis used a novel multi-method approach to explore behaviour maintenance, with a particular focus on weight loss maintenance (WLM). Methods: A three stage, multi-method approach included: (1) A systematic review of behavioural theories to identify theoretical explanations for behaviour maintenance and to examine the relationships between these explanations; (2) An N-of-1 study of WLM assessing theoretical predictors of maintained behaviour based on the systematic theory review, which employed ecologic momentary assessment, wireless body scales, and activity monitors in 12 obese people who had lost at least 5% weight in the previous year, analysed through cross-correlations of time series; (3) Data-prompted semi-structured, longitudinal interviews with individuals who participated in the N-of-1 study to explore their experiences of WLM, prompted by personal data including summaries of N-of-1 data, pictures, notes and graphs, analysed using the Framework method. Findings: (1) Systematic review: out of 117 identified behaviour theories, 100 met the inclusion criteria. The main theoretical themes identified to underpin behaviour change maintenance included maintenance motives, self-regulation, habits, psychological resources and environmental/social influences; (2) N-of-1 study: for 12 participants a range of maintenance-related theoretical variables showed differential impact on ability to maintain weight, engage in physical activity and x follow a personal WLM plan. The combination of predicting variables that had significant impact on outcome variables was unique for each individual; (3) Data-prompted interviews: most of the theoretical explanations from the systematic theory review adequately accounted for participants’ experiences. Additional emergent themes included: competing goals, prioritising, and preparatory strategies that enhanced self-regulation. Using personal data summaries proved valuable in evoking narratives regarding unique experiences of WLM. Discussion: A range of theoretical explanations were identified and proved useful in explaining behaviour maintenance in the area of WLM. The main conclusion derived from the thesis is that behavioural interventions need to tap into relevant behavioural explanations and deliver intervention components in a timely manner to support individuals to maintain behaviour change. Interventions should include elements of choice and customisation and should be adaptable to personal needs. The main study strengths included employment of novel methods and technology. The main limitation included N-of-1 analytical challenges and scalability of the applied design. Future research should develop behaviour maintenance theory further and explore which combinations of WLM strategies, in which individuals, support effective WLM.