Perceptions of physical attractiveness vary across cultural groups, particularly for female body size and shape. It has been hypothesized that visual media propagates Western "thin ideals." However, because cross-cultural studies typically consider groups highly differentiated on a number of factors, identifying the causal factors has thus far been impossible. In the present research, we conducted "naturalistic" and controlled experiments to test the influence of media access on female body ideals in a remote region of Nicaragua by sampling from villages with and without regular TV access. We found that greater TV consumption remained a significant predictor of preferences for slimmer, curvier female figures after controlling for a range of other factors in an ethnically balanced sample of 299 individuals (150 female, aged 15-79) across 7 villages. Within-individual analyses in 1 village over 3 years also showed an association between increased TV consumption and preferences for slimmer figures among some participants. Finally, an experimental study in 2 low-media locations demonstrates that exposure to media images of fashion models can directly impact participants' body size ideals. We provide the first converging cross-sectional, longitudinal, and experimental evidence from field-based research, that media exposure can drive changes in perceptions of female attractiveness.