Unfavourable dietary patterns and lower physical activity were statistically associated with poorer sleep quality among university students, with physical activity mediating the diet-sleep relationship and sex moderating this indirect association, with stronger effects observed among females.
Poor sleep quality was substantially more prevalent among female university students than male students.
Machine-learning feature selection identified nine dietary behaviours statistically associated with sleep quality.
Physical activity formed part of a statistically significant indirect association between dietary behaviour and sleep quality.
Sex moderated the path from physical activity to sleep quality in the mediation model.
The indirect association between dietary behaviour and sleep quality through physical activity was significant for both sexes but stronger among females.
The study used a cross-sectional design among university students with anthropometric measurements and validated questionnaires.
This research suggests that among university students, unhealthy eating habits — such as consuming fast food, fried meals, sweetened drinks, energy drinks, and alcohol — are associated with worse sleep quality, while eating vegetables, curd cheese, and wholegrain bread is linked to better sleep. The study also found that physical activity plays a connecting role between diet and sleep: students with better dietary habits tended to be more physically active, and more physical activity was in turn linked to better sleep. Notably, female students experienced poor sleep at a much higher rate (45%) compared to male students (15%). The study further found that the indirect connection from diet to sleep through physical activity was stronger in women than in men, even though it was statistically meaningful for both sexes. Sex appeared to specifically influence how strongly physical activity was related to sleep quality, with the relationship being more pronounced for female students. These findings highlight that diet and physical activity do not operate in isolation — their combined lifestyle patterns matter for sleep health, and these patterns may affect men and women differently. This research suggests that efforts to improve sleep among university students might benefit from addressing both eating habits and physical activity together, rather than focusing on either alone, and that approaches tailored to sex differences could be more effective. However, because this was a cross-sectional study — meaning it captured a single snapshot in time — it cannot confirm that dietary habits or physical activity directly cause changes in sleep quality. Longitudinal or experimental studies would be needed to establish causal relationships.
Domaradzki J. (2026). Sex Moderates the Mediating Effect of Physical Activity in the Relationship Between Dietary Habits and Sleep Quality in University Students.. Nutrients. https://doi.org/10.3390/nu18010026