Psychometric Properties of the Turkish Version of the Dietary Fat and Free Sugar-Short Questionnaire (DFS-TR) in Adults: A Validity and Reliability Study

Background/Objectives: The aim of this study was to translate the Dietary Fat and Free Sugar-Short Questionnaire (DFS) into Turkish (DFS-TR) and to establish its construct validity and reliability. Methods: Quota sampling was used to ensure demographic homogeneity across gender and age groups. Participant distribution by age categories was proportionally aligned with the demographic statistics of the adult Turkish population. The study comprised 314 participants aged 19–64 years (38.78 ± 12.10), of which 54.5% were female. The data collection form consisted of demographic characteristics, anthropometric measurements, information on eating habits, DFS-TR, the Food Frequency Questionnaire (FFQ), and the Power of Food Scale (PFS). Results: Test–retest reliability was confirmed in the 314 participants with a 4-week interval (r = 0.997, p < 0.01). The Cronbach α reliability coefficient was α = 0.777. Using the split-half method, the correlation coefficient between the two halves was 0.681, the Spearman–Brown coefficient was 0.811, and the Guttman coefficient was 0.809. Participants’ total DFS-TR scores and sub-dimension scores varied according to age, education level, income level, anthropometric characteristics, physical activity, and dietary habits, but did not vary according to gender or marital status. To investigate convergent validity, participants’ DFS-TR scores were correlated with the FFQ and PFS. DFS-TR scores showed a significant correlation with the percentage of energy from saturated fat and free sugar assessed by the FFQ. Positive relationships were found between DFS-TR scores and the total PFS score, particularly with the sub-dimension scores for food available and food present. Conclusions: The DFS-TR can be used as a reliable and valid measurement tool for estimating saturated fat and free sugar intake among Turkish adults.