Planetary health diet adherence, nutritional adequacy, and environmental footprints: a cross-sectional study in Turkish adults

Background Although the EAT–Lancet Planetary Health Diet (PHD) is recognized as a global reference model for sustainable nutrition, data on the implications of this framework in Türkiye are limited. This study aims to assess the relationship between adherence to the PHD among adults in Türkiye and both diet quality and environmental footprints. Methods Data were collected from individuals aged 18–64 from a family health center in Ağrı province. Dietary intake was assessed using a single 24-h dietary recall. Adherence to the PHD was quantified using the Planetary Health Diet Index (PHDI), while diet quality was evaluated with the Healthy Eating Index–2020 (HEI-2020). Environmental impacts were estimated using carbon footprint (CF) and water footprint (WF) values derived from the SU-EATABLE LIFE and SHARP-ID databases. Results Five hundred and seventy-one participants were included in the study; the mean age of the participants was 36.5 ± 12.3 years and 59.9% were female. The PHDI and HEI mean scores were 51.9 ± 12.7 and 47.5 ± 11.8, respectively. Multivariable logistic regression analysis demonstrated a strong positive relationship; participants in the highest PHDI quintile had significantly higher odds of better diet quality compared to the lowest (AOR = 9.052, 95%CI: 4.040–20.278, p < 0.001). Furthermore, continuous analysis confirmed that each unit increase in PHDI score was independently associated with a higher HEI score (AOR = 1.078, 95%CI: 1.053–1.103, p < 0.001). Among the environmental indicators, CF was inversely associated with HEI (AOR = 0.221, 95%CI: 0.125–0.393, p < 0.001), and WF was positively associated with HEI (AOR = 1.003, 95%CI: 1.002–1.005, p < 0.001). Conclusion Higher adherence to the PHDI was linked to a better HEI score and lower environmental footprints (CF and WF). These findings highlight the importance of the PHD in promoting environmental sustainability alongside higher diet quality while reducing environmental burdens.