Abstract

Background: Obesity is a global public health challenge, and YouTube has emerged as a primary source of health information. To develop effective health communication strategies, researchers must understand the relationship between content topics and user engagement. However, systematic analyses of obesity-related Koreanlanguage YouTube content are limited. Methods: We collected Korean-language YouTube videos uploaded between January 1, 2020, and September 30, 2025, using obesity-related keywords. We performed Latent Dirichlet Allocation (LDA)-based topic modeling on video subtitles. We compared user engagement metrics (exposure velocity, engagement rate, interaction velocity, and popularity index) across six uploader types: individual creators, media, hospitals, medical professionals, government/public institutions, and academic organizations. Results: Of the 2,798 videos identified, those by individual creators were the most prevalent (43.4%). User engagement metrics differed significantly across uploader types (P＜0.001). Individual creators led in exposure velocity (10.91 views/day), whereas hospitals exhibited the highest engagement rate (1.8%). LDA modeling identified 11 topics, categorized broadly into medical treatment (49.8%) and lifestyle management (34.3%). Topic distribution differed significantly across uploader types (P＜0.001); specifically, individual creators emphasized exercise and diet (29.0%), whereas hospitals concentrated on bariatric surgery (43.7%). Practical topics, such as abdominal obesity management (exposure velocity: 111.99 views/day) and home training exercises (exposure velocity: 27.54 views/day), elicited substantially higher user engagement than did specialized medical topics (P＜0.001). Conclusion: User engagement and topic distribution in obesity-related YouTube content differ by uploader type. Individual creators drive faster dissemination, and practical, action-oriented topics disseminate more rapidly than specialized medical topics.