AIM: To understand the process of behaviour change through the experiences of people with Type 2 diabetes engaged in an 8-month diabetes remission intervention including a 2-month weight loss phase with the use of a very low energy diet (VLED), and a 6-month, structured weight maintenance phase. METHODS: Data were collected in three semi-structured interviews at baseline, week 8 (end of the weight loss phase), and month 8 (end of the weight maintenance phase). Longitudinal inductive thematic analysis was used to analyse participants' narratives and identify change over time. RESULTS: Eleven of 18 participants completed all three interviews. The following themes of change were identified in their narratives: (1) 'Building behavioural autonomy' as a process of growing confidence to engage in health behaviours that are independent of those of other people; (2) 'Behavioural contagion' describing how one's new health behaviours tend to affect those of other people; (3) 'From rigid to flexible restraint', reflecting the changes in attitudes and behaviours required for a successful adaptation from weight loss to weight maintenance; and (4) 'Shift in identity', representing changes in the participants' perceptions of themselves. CONCLUSIONS: This longitudinal qualitative study provided new insights into how behaviour change is experienced by people with Type 2 diabetes engaged on a weight management intervention using VLED, contributing to theoretical and practical understanding of weight management behaviours. The themes identify potential areas in which individuals can be supported in achieving dietary diabetes remission and long-term maintenance of weight loss.