Your media diet is impacting your actual diet: The effects of influencer “What I Eat in a Day” YouTube videos on influencer perceptions and nutrition behaviors

Objective: Social media influencers frequently post "What I Eat in a Day" (WIEIAD) vlogs, shaping dietary perceptions and behaviors among young audiences. There is concern that these videos contribute to negative outcomes, such as disordered eating and unhealthy social comparisons. While prior research largely focuses on the effects of short-form content (e.g., from TikTok), this study examines the impact of long-form WIEIAD videos on perceptions about the content creators and nutrition-related behaviors, and measures behavior by asking participants to select an apple or cookie after watching a WIEIAD video. Methods: Using a 2 × 2 experimental design (N = 289), participants viewed WIEIAD YouTube videos varying in the presence and absence of sponsorship (i.e., either a service or product) and physical health benefits of the diet. Results: Results indicate that sponsorship increased perceptions of influencer trustworthiness and attractiveness but decreased authenticity and parasocial interaction. Additionally, exposure to sponsored content increased the likelihood of selecting a cookie, supporting media priming effects in nutrition behavior. However, disclosure of physical health benefits did not influence snack choice. There was also a relationship between intentions to change diet and opting out of the snack. Conclusions: These findings raise important considerations for digital health communication, influencer regulation, and content literacy interventions aimed at mitigating the negative health effects of social comparison and commercial nutrition messaging online.