ABSTRACT We used a mixed-methods design to test a novel weight bias intervention and understand current attitudes toward people with higher weight and weight-inclusive care among medical students (N = 80). The intervention was embedded in curriculum and uniquely focused on delegitimising the use of weight as a heuristic for health. Almost half of participants (43.8%) responded to both pre- and post-intervention surveys. These participants found the intervention acceptable; and reported significant pre-post reductions in weight bias and endorsement of using weight as a heuristic for health. Less engaged participants reported significantly greater endorsement of using weight as a heuristic for health at pre-intervention. One central theme emerged from pre-intervention qualitative responses, related to how medical students scoped both the problem and the solution. This consisted of three sub-themes: (1) problematizing the system and clinician (and their weight bias), (2) problematizing the patient (who was responsible for their own health), and (3) problematizing the medical condition (weight and health behaviors as problems for the clinician to solve). Participants often showed evidence of several and sometimes contradictory ways of problem-scoping. Problematizing the patient, including weight-stigmatizing assumptions, was particularly pronounced among less engaged participants (i.e. those who did not complete the post-survey). Findings suggest that the intervention may be acceptable and effective in reducing weight bias in medical students who already have lower levels of bias than their peers. Qualitative findings suggest that, even when medical students recognize the harmful impacts of weight stigma and the benefits of weight-inclusive care, approaches to care may remain weight-centric. Together, the findings suggest a key challenge for weight bias reduction among medical students lies in addressing problem-scoping that may encourage weight bias and weight-centric care, and reaching the population most in need of intervention – students with high levels of weight bias.