Background: Video gaming is a highly prevalent leisure activity globally, with complex associations across multiple health domains. Methods: This narrative review critically appraised the existing literature identified through targeted searches of PubMed and Google Scholar to synthesise evidence on associations between video gaming and psychosocial stress, physical activity, sleep quality, eating behaviour, and diet quality. Theoretical, biological, and psychosocial mechanisms underlying these relationships were examined, and methodological limitations and research gaps were identified. Results: The relationships between video gaming and health outcomes appear bidirectional and context dependent. While video gaming may provide short-term stress relief and social connection, frequent or prolonged gaming may be associated with sedentary behaviour, physical inactivity, impaired sleep quality, disrupted eating patterns, and poorer diet quality. These associations may vary by age, sex, gaming duration, timing, content, and motivational drivers. Gaming-related cognitive absorption and physiological arousal may influence appetite regulation, sleep onset, and stress responses, while temporal displacement and environmental factors, such as food availability and marketing exposure, also contribute. Conclusions: An integrated biopsychosocial framework is proposed to describe the interconnected pathways through which video gaming may influence health, incorporating biological arousal, psychological immersion, and social and environmental contexts. Significant gaps remain, including the scarcity of longitudinal studies, limited consideration of moderating factors, and inconsistent measurement of gaming behaviours. Addressing these gaps is essential for refining public health surveillance and supporting the development of evidence-based strategies that promote healthy gaming behaviours while preserving potential psychosocial benefits.