Psychometric Evaluation of the German Version of the Dietary Fat and Free Sugar-Short Questionnaire

Background: The Dietary Fat and free Sugar – Short Questionnaire (DFS) is a cost- and time-efficient self-report screening instrument to estimate dietary intake of saturated fat and free sugar. To date, only the English version has been psychometrically evaluated. We assessed the psychometric characteristics of the German version of the DFS in normal weight, overweight and obese individuals. Method: 65 adult participants completed a German translation of the DFS and a validated food frequency questionnaire (FFQ). We correlated participants’ percentage of energy intake from saturated fat and free sugar from the FFQ with the DFS scores. To establish test-retest reliability, participants completed the DFS a second time. To investigate convergent validity, we correlated participants DFS scores with self-reported eating behaviour and sensitivity to reward. Results: DFS scores correlated with percentage of energy from free sugar (rs = .443) and saturated fatty acids (rs = .258) but not with non-target nutrients. The correlation between DFS scores and percentage energy from free sugar was not moderated by BMI, whereas the correlation with percentage energy from saturated fat slightly decreased with BMI. Intra-class correlation was .801, suggesting excellent test-retest reliability. DFS scores correlated significantly with restraint of eating behaviour (rs = -.380) and feelings of hunger (rs =.275). Correlations of the DFS score with disinhibited eating and sensitivity to reward failed to be significant. Conclusion: Our results suggest that the German version of the DFS provides a reliable and valid estimation for the dietary saturated fat and free sugar intake of normal weight, overweight, and obese individuals.