Mental body representations are malleable and can be influenced by auditory cues. In the “Footsteps illusion,” real-time alterations of walking sounds simulate those produced by heavier or lighter bodies, affecting perceptions of body weight, speed, and gender traits, and triggering emotional, behavioral, and physiological changes. While body illusions are known to affect social attitudes, less is known about how social factors influence body perception malleability. We investigated whether social support networks modulate this malleability using the “Footsteps illusion,” given the social relevance of body weight. A total of 105 participants experienced three footstep sound conditions (heavier, lighter and control). We collected demographic, behavioral, physiological, and subjective data, along with body image and eating disorder questionnaires. Results showed that larger social support networks correlated with higher body image satisfaction and fewer eating disorder symptoms. Notably, the illusion had a stronger effect on those with smaller social networks, highlighting the moderating role of social support.