Effects of nutritional interventions on competitive performance and dose‒response relationships among esports players of different skill levels: a systematic review and three-level meta-analysis

BACKGROUND AND OBJECTIVES: Esports place exceptional demands on neuropsychological capacities; however, a systematic and quantitative synthesis of the specific efficacy of nutritional interventions across various tasks and competitive populations remains absent. This study aims to evaluate the impact of nutritional supplementation on cognitive function and competitive performance in esports players and to explore key moderating variables. METHODS: Electronic databases, including Web of Science, PubMed, and Scopus, were searched (up to January 25, 2026). Thirteen randomized controlled trials (RCTs) met the inclusion criteria. A three-level random-effects model was employed to calculate the pooled effect size (Hedges' g), with sources of heterogeneity explored through subgroup analyses and meta-regression. RESULTS: Nutritional interventions significantly enhanced esports-related performance (g = 0.92), with the most pronounced benefits observed in processing speed (g = 1.18) and executive function (g = 1.06). Subgroup analyses revealed significant gains in both professional (g = 0.97) and amateur groups (g = 0.92), while the improvement in first-person shooter (FPS) games (g = 0.96) appeared to surpass that in multiplayer online battle athlete (MOBA) games. Meta-regression indicated no significant linear correlation between caffeine dosage and effect size. GRADE assessment categorized the quality of evidence mostly as "low" to "moderate." CONCLUSIONS: Nutritional interventions demonstrate significant potential for optimizing multidimensional cognitive performance in esports players, particularly in enhancing fundamental reaction speed and high-level decision-making processes. While the findings exhibit a degree of robustness, their practical application should be cautiously evaluated within specific competitive contexts due to current limitations in evidence certainty and significant interstudy heterogeneity. Future research characterized by gender balance and mechanistic orientation with long-term intervention protocols is warranted to elevate the level of clinical evidence.