Obesity is a growing epidemic fuelled by unhealthy behaviours and associated with significant comorbidities and financial costs. While behavioural interventions produce clinically meaningful weight loss, weight loss maintenance is challenging. This may partially be due to failure to target stress and emotional reactivity. Mindfulness-based stress reduction (MBSR) reduces stress and emotional reactivity and may be a useful tool for behaviour change maintenance. This study seeks to provide a mechanistic understanding for clinical trials of the benefits of MBSR for weight loss maintenance by examining changes in functional connectivity (FC) and the association of these changes with clinical outcomes.