Technical Abstract: Stories can serve as powerful tools for health interventions. Story immersion refers to the experience of being absorbed in a story. This is among the first studies to analyze story immersion’s role in health video games among children by addressing two main questions: Will children be more immersed when the main characters are similar to them? Do increased levels of immersion relate to more positive health outcomes? Eighty-seven 10-12 year-old African-American, Caucasian, and Hispanic children from Houston, Texas, played a health videogame, "Escape from Diab", featuring a protagonist with both African American and Hispanic phenotypic features. Children's demographic information, immersion, and health outcomes (i.e., preference, motivation, and self-efficacy) were recorded and then correlated and analyzed. African-American and Hispanic participants reported higher immersion scores than Caucasian participants (p=.01). Story immersion correlated positively (P values < 0.03) with an increase in preference for fruits and vegetables (r=.27), intrinsic motivation for water (r=.29), vegetable self-efficacy (r=.24), and physical activity self-efficacy (r=.32). Ethnic similarity between video game characters and players enhanced immersion and several health outcomes. Effectively embedding characters with similar phenotypic features to the target population in interactive health video game narratives is likely to be important in motivating children in obesity prevention and intervention.