April 7-9, 2022 • Hyatt Regency • Lexington, KY
Communication Strategies to Promote Comprehensive Well-being
Communication Strategies to Promote Comprehensive Well-being
Abstract: Celebrity Credibility and Endorsement on Decision-Making about Weight-Loss Supplements: Predictors of Intent to Use
Rationale: Celebrities are common endorsers of weight-loss supplements. Incorporating weight-loss supplements into an everyday diet is highly contested because supplements are not regulated by a governmental regulatory agency. There are no guidelines for what can be communicated in supplement advertisements or who can endorse supplements. Weight-loss supplements are extremely popular among adolescents and emerging adults, the group which experiences the most negative and deadly outcomes from use. This study examines the impact of celebrity credibility on emerging adults’ decision-making about weight-loss supplements. Method: College students (N = 291) participated in an experimental design with three randomized stimuli. Most students had never taken a weight-loss supplement (n = 239, 82.1%); however, 52 participants reported using weight-loss supplements in the past, including 11 students who were currently taking weight-loss supplements. Students were exposed to one of three weight-loss supplement celebrity endorsers: Dr. Mehmet Oz, Biggest Loser trainer Jillian Michaels, and Kim Kardashian. Participants then completed the Celebrity Credibility Scale, which measures attractiveness (α = .849), trustworthiness (α = .959), and expertise (α = .975), and answered questions about celebrity influence, celebrity advice, and intent to use supplements. Results: Michaels was the most credible celebrity across all credibility categories. Oz was deemed trustworthy and an expert, while Kardashian was ranked as only attractive. There were significant differences between groups for endorsement influence on intent to use, F(2, 288) = 11.830, p < .001. Post hoc analysis revealed individuals who were exposed to Kardashian were significantly less likely to be influenced (M = 1.84, SD = 1.027, p < .01) than those exposed to Michaels and Oz. There were also significant differences between groups and whether they would take the celebrity’s advice on using supplements, X2 (2, N = 291) = 33.52, p < .01. Participants in the Kardashian group were significantly less likely to take her advice than those in the Michaels or Oz groups. A mediation analysis using PROCESS (Hayes, 2013) found that there is a significant direct effect between celebrity credibility and intent to use supplements (β = -1.26, S. E. = .168, p < .001, 95% CI = -1.59, -.93). The manipulation was a significant mediator of this relationship (IE = -.134, β = -.75, S. E. = .05, p < .001, 95% CI = -.245, -.057). Exposure to different celebrities influenced celebrity credibility and participants’ intent to use. Implications: Medical expertise was not the key factor in use intention. Instead, trustworthiness was key. It raises questions about “legitimate medical knowledge” when it comes to supplements and whether knowledge of fitness and nutrition is more important than medical knowledge. Second, the attractiveness finding problematizes how weight-loss supplements are seen: as a health or a beauty item? Although weight-loss supplements are normally associated with beauty, young adults may see them more related to fitness and turn to a celebrity endorser who represents fitness. It is also possible participants may have idealized notions of what bodies are healthiest and as such may have attributed credibility to the most idealistic “healthy” body.