The relationship between physical activity, healthy eating behaviors, and quality of life among university students

Previous research has often examined physical activity, dietary behaviors, and quality of life (QoL) through bivariate associations, with comparatively limited attention to subdomain-level patterns. This study aimed to investigate the multidimensional relationships between physical activity, healthy eating behavior subdomains, and QoL subdomains among university students, and to examine differences across exercise-frequency groups. This cross-sectional correlational study included 385 university students (237 female, 148 male) from various universities in Istanbul, Türkiye. Data were collected using a demographic information form, the IPAQ-SF, the Healthy Eating Attitudes Scale, and the WHOQOL-BREF. Pearson correlation, independent-samples t tests, and one-way ANOVA were conducted. Physical activity was significantly associated only with the psychological domain of QoL, although the magnitude of this relationship was very small (r = .107, p < .05). Nutritional knowledge and positive eating behaviors were positively correlated with all QoL subdomains, whereas unhealthy eating behaviors showed negative associations with the physical, social, and environmental domains. Students who exercised regularly demonstrated significantly higher QoL scores across all domains, although the corresponding effect sizes were generally small, with the largest difference observed in the social domain (|d|= 0.43). A graded frequency-related pattern was identified: positive eating behavior scores increased with exercise frequency (F = 9.93, p < .001, η 2 = .049), while unhealthy eating behavior scores decreased (F = 15.80, p < .001, η 2 = .076). The findings indicate that the relationships between physical activity, healthy eating behaviors, and QoL are domain-specific. The frequency-related differences in dietary behaviors should be interpreted cautiously and do not establish a causal dose–response effect; nevertheless, they support the potential value of holistic university health promotion programs that encourage regular physical activity participation.