<![CDATA[Adolescent athletes' eating behavior is shaped by their training environment, and coaches are often the main reference for dietary information, especially when sports nutritionists are hard to reach. This study analyzed the role of coaches in shaping the nutritional behavior of adolescent athletes in Bengkulu City, Indonesia. Conducted in 2023, it used an explanatory sequential mixed-methods design: a cross-sectional survey of 96 athletes aged 13–17 years from six sports, followed by semi-structured interviews with 10 coaches. Coach roles (four dimensions) and nutritional behavior were measured with questionnaires whose validity and reliability had been tested, and were analyzed using one-way ANOVA, Pearson correlation, multiple linear regression, and thematic analysis. The mean nutritional behavior score was 66.3 out of 100. Athletes who rated their coaches' role as high scored higher (70.5) than those in the low category (59.5; difference 11.0; 95% CI 6.0–16.1). The total coach-role score correlated moderately and positively with nutritional behavior (r = 0.52; p < 0.001). In the regression model (R² = 0.31), only motivational support and guidance was significant (β = 0.34; p = 0.006). Interviews showed that coaches' nutrition knowledge came from experience rather than formal training, and that dietary regulation was largely limited to competition periods. Coaches' roles are closely related to adolescent athletes' nutritional behavior; therefore, basic nutrition training for coaches and collaboration with nutrition professionals, parents, and schools should be strengthened.]]>
