This study examines how adolescents internalize fatphobic body norms through sustained exposure to influencer-driven aesthetic narratives of health. The term “fatphobic aesthetic moralism” is used as an interpretive framework to describe how influencer-driven content may transform aesthetic and health-related body norms into moral evaluations, whereby thinness, muscularity, and visible self-discipline become associated with responsibility, self-control, and personal worth. Drawing on survey data from 1,032 Spanish adolescents aged 12-17 years and semi-structured interviews with educators, health professionals, and social workers, the results show that adolescents who identify influencers as role models for health and beauty show a higher prevalence of elevated fatphobic attitudes. Quantitative results distinguish the greater overall frequency of peer referents from the higher prevalence of elevated fatphobic attitudes among adolescents selecting influencers, while qualitative results reveal how influencers function as informal pedagogues whose authority derives from algorithmic visibility and affective proximity. Professionals emphasized that these narratives naturalize fatphobia by framing bodily conformity as evidence of effort and virtue, while deviation signals irresponsibility or failure. Within this framework, influencer culture can be understood as a digital pedagogy through which body norms may become moralized via aesthetic codes, producing enduring hierarchies of worth that extend beyond beauty ideals into the evaluation of the self and others.