The Role of Influencer Credibility and Parasocial Interaction in Shaping Healthy Eating Intention: A PLS-SEM Study Comparing Instagram and YouTube

This study examines how food influencer credibility is associated with healthy eating intention through parasocial interaction, drawing on Social Cognitive Theory, Parasocial Interaction Theory, and Media Richness Theory (MRT). Using PLS-SEM, data from 600 social media users in Turkey (n = 300 Instagram, n = 300 YouTube) who follow food influencers sharing healthy eating content were analyzed. Results showed that influencer credibility positively predicted both parasocial interaction (β =.666, p <.001) and healthy eating intention (β =.260, p <.001). Parasocial interaction exhibited a partial mediation pattern in the credibility–intention relationship (indirect effect =.323; VAF = 55.4%). Contrary to MRT expectations, PLS-MGA revealed no significant platform differences in the structural paths. As an exploratory finding, the direct effect of nutrition literacy on healthy eating intention was stronger among YouTube users (β =.338) than Instagram users (β =.183, p =.034). The moderating effect of nutrition literacy on the parasocial interaction–intention link was not statistically significant (β =.068, p =.086). Monte Carlo power analysis confirmed statistical power above.999 for all structural paths. The study contributes to health communication by providing evidence for parasocial interaction as a mediating channel in the nutrition context, by empirically testing the boundary conditions of MRT in a health communication setting, and by offering non-WEIRD evidence from a Turkish sample. The findings suggest that public health campaigns may leverage influencer credibility and parasocial bonds to promote healthy eating intentions.