Change starts with the body: Interoceptive appreciation mediates the effect of mindfulness training on behavior change – an effect moderated by depression severity

•In mindfulness meditation, people increasingly listen to and trust body sensations.•Mindful appreciation of body signals partially mediates behavior change initiation.•In depression, regaining body trust plays a role in a mindful path towards change. Mindfulness catalyzes health behavior change. Yet, interoception is dysregulated in depression, potentially impairing behavioral activation. We examined the mediating role of interoceptive appreciation, as measured by how much one trusts and listens to internal bodily signals, on behavior change. Primary care patients with depression, anxiety, or stress disorders related to chronic illness were randomized to Mindfulness Training for Primary Care (MTPC) using the Mindful Behavior Change curriculum or a low-dose mindfulness comparator. Participants (N = 274) completed the Multidimensional Assessment of Interoceptive Awareness (MAIA) at 0 and 8 weeks. At week 7, participants chose a health behavior action plan. During weeks 8–10, participants reported their action plan initiation (API) level. We investigated the effect of MTPC on API level (MTPC-API), the mediating role of interoceptive appreciation (Body Listening [MAIA-BL] + Trusting [MAIA-T]), and baseline depression severity as a moderator. MTPC had a significant direct effect on API. Interoceptive appreciation (MAIA-BL + MAIA-T) had a significant indirect effect on API (CI=0.15–0.56). Without depression (n = 76), MAIA-BL partially mediated MTPC-API (CI=0.02–0.87). With moderate-to-severe depression (n = 132), MAIA-T partially mediated MTPC-API (CI=0.01–0.85). Interoceptive appreciation helps people listen to motivating bodily signals. In depression, regaining body trust may be an important step on a mindful path towards change.