Planetary Health Diet adherence among Spanish university students: associations with lifestyle and sustainability perception.

OBJECTIVES: The Planetary Health Diet (PHD) has been proposed as a dietary pattern aligned with planetary boundaries to promote both human and environmental health. This study aimed to assess adherence to the PHD among university students in Spain and to identify sociodemographic and lifestyle factors, as well as sustainability perceptions associated with adherence. METHODS: A cross-sectional study was conducted during the 2024-2025 academic year among Spanish university students aged ≥18 y without self-reported chronic disease, eating disorders, pregnancy, or lactation. Participants completed a self-administered questionnaire that included: 1) sociodemographic and anthropometric characteristics, 2) lifestyle factors, 3) perceptions about sustainable diets, and 4) dietary intake through a food frequency questionnaire. In the absence of validated Planetary Health Diet Index (PHDI) cutoffs, adherence categories were defined a priori to facilitate ordinal analyses. RESULTS: Adherence to the PHD was assessed among 710 university students (21.98 y; 68.3% female; mean body mass index 22.7 kg/m2) using the PHDI. The mean PHDI score was 58.6 (SD 13.85) with a maximum of 150. In univariate analyses, age (P < 0.001), field of study (P = 0.03), type of residence (P < 0.001), municipality size (P = 0.01), and physical activity (P < 0.001) were associated with PHDI scores. In multivariable models, intense physical activity was independently associated with higher adherence to the PHD (2.18; 95% confidence interval 1.50-3.17), whereas students enrolled in non-health sciences programs showed lower odds of higher adherence compared with health sciences students (0.73; 95% confidence interval 0.54-0.98), after adjustment for age and total energy intake. CONCLUSIONS: Spanish university students showed a mean PHDI score of 58.6 out of 150. Higher physical activity and enrollment in health sciences programs emerged as independent correlates of higher adherence. These findings suggest potential implications for public health, although confirmation in longitudinal studies is required.