Adherence to the Planetary Health Diet and Its Association with Diet Quality in the Young Adult Population of Türkiye: A Large Cross-Sectional Study

To advance both human health and environmental sustainability, it’s crucial to assess the adaptation to new dietary trends emerging in this field. This study aimed to explore the relationship between diet quality and the principles of planetary health diet in young adults studying at university. This cross-sectional study consisted of 945 young adults with a mean age of 20.1 ± 1.34 y (582 females, 363 males). A questionnaire form containing socio-demographic information (age, gender, education level), anthropometric measurements (body weight and height), and a 24 h dietary record form for three consecutive days was applied. The scores of the Planetary Health Diet Index (PHDI) and the Healthy Eating Index-2020 (HEI-2020) were calculated according to the dietary records. The mean total scores of the PHDI and HEI-2020 were 59.9 ± 14.16 and 54.2 ± 10.87, respectively. The association between the HEI-2020 score and the PHDI score was significant (p = 0.003). A one-unit increase in the unadjusted HEI-2020 score caused a 0.429 unit decrease in the PHDI score (95% CI: −0.709; −0.149). The findings underscore the imperative for targeted interventions and educational programs to enhance the PHDI and HEI-2020 scores, promoting individual well-being and environmental sustainability in the university.