Adaptation of the sustainable healthy diet scale into Turkish

Nutrition is a key determinant in maintaining health and sustaining ecological balance. The aim of this study was to adapt the Sustainable Healthy Diet Scale (SHDS) into Turkish and to evaluate its validity and reliability. This methodological study was conducted between March and April 2025. A total of 621 individuals aged between 18 and 65 years participated in the study (68.6% female, 31.4% male; mean age: 33.13 ± 11.84 years). Data were collected online using a questionnaire prepared via Google Forms, and participants were recruited using the snowball sampling method. As part of the reliability assessment of the scale, internal consistency was evaluated using Cronbach's alpha (α), McDonald's omega (ω), and Guttman's lambda (λ) coefficients, while temporal stability was assessed using the test–retest method. Construct validity was examined through exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). To form two balanced groups for EFA and CFA, propensity score analysis and hierarchical clustering methods were applied. Accordingly, EFA was conducted with 236 participants and CFA with 385 participants. Prior to the EFA, the prerequisite tests—Kaiser-Meyer-Olkin (KMO) and Bartlett's test of sphericity—were conducted. The KMO test result (0.92) indicated that the sample size was adequate for factor analysis, while the result of Bartlett's test of sphericity (χ² = 2291.98. p < 0.001) showed that there were statistically significant correlations among the items, supporting the suitability of the data for factor analysis. As a result of the EFA, the SHDS, consisting of 18 items, was found to be structured under six factors. The factor loadings of the items ranged from 0.47 to 0.80. and the total explained variance was 63%. The factors were labeled as Nutrition, Environment, Social, Economic, Safety, and Taste. The fit indices obtained from the CFA indicate that the model demonstrates a good fit with the data. Reliability analyses revealed that the scale demonstrated a high level of internal consistency (Cronbach's Alpha = 0.939; Omega = 0.940). Moreover, the test-retest reliability, used to assess the temporal stability of the scale, was also found to be statistically significant (r = 0.63; p < 0.001). The results of this study indicate that the Turkish adaptation of the SHDS is a valid and reliable measurement tool that can be used to assess food purchasing behaviors aligned with a sustainable healthy diet, particularly among health professionals working in the field of Nutrition and Dietetics.