Effects of Embodied Agent Body Type on Perceptions and Dietary Intentions in Digital Health Counseling

ABSTRACT Embodied Conversational Agents (ECAs) are increasingly used for health education, yet the role of an agent's physical embodiment remains relatively underexplored. This study examines how body mass index (BMI) cues in an embodied agent relate to user perceptions, trust in medical content, and health‐related intentions during a brief dietary counseling interaction focused on diabetes prevention. In a between‐subjects experiment, participants interacted with one of three visually distinct versions of the same healthcare coach, representing underweight, normal‐weight, or obese body types. Across conditions, participants demonstrated improvements in dietary intentions, while significant increases in diabetes memory outcomes were observed only in the underweight and normal‐weight conditions. Increases in overall behavior change intention were observed only in the underweight condition. Subjective evaluations indicated that the normal‐weight agent was rated higher on realism, likability, and interaction quality, while post‐interaction perception ratings suggested that more extreme body representations were sometimes perceived as less comfortable or less appropriate for a health advisory role. Together, these results suggest that visual body type cues may be associated with differences in users' subjective experiences of embodied health counseling agents, while evidence for broader differences in learning and motivation‐related outcomes should be interpreted cautiously.