'It's not a diet, it's a lifestyle': a longitudinal, data-prompted interview study of weight loss maintenance

Objective: To advance understanding of the individual and environmental factors underpinning weight loss maintenance. Design: Semi-structured, data-prompted interviews were conducted with twelve overweight adult participants (three men, nine women) who had lost over 5% of their body weight in the year before baseline. Participants gathered daily data through wireless scales, activity monitors (Fitbit (TM)), ecological momentary assessment and experience sampling (taking photographs, writing notes). They were interviewed at 3- and 6-months post baseline. Interview stimuli included personal data of weight and activity graphs, correlations of psychological factors, and self-generated notes and photographs. Interview data were analysed using the Framework Method, applying pre-specified maintenance-relevant theoretical themes. Results: The theoretical Framework provided a good fit for the narratives, with five main themes underpinning successful weight loss maintenance: sustained motivation, effective self-regulation, plentiful resources, habit formation and a supportive environment. Additionally, participants reported an identity shift from being a dieter to accepting a new healthy lifestyle. Goal prioritising and allowing for occasional controlled lapses enhanced weight loss maintenance. Conclusions: This study successfully used the novel method of data-prompted interviews to explore weight loss maintenance experiences with new explanations emerging from the data. Future research should further develop behaviour change maintenance theory and data-prompted interview method.