Turkish adaptation of the Chrononutrition Profile–Questionnaire (CP-Q): Validity and reliability study

The Chrononutrition Profile–Questionnaire (CP-Q) is a behavioral tool for assessing nutrition timing in relation to the sleep–wake cycle. This methodological cross-cultural adaptation and validation study aimed to adapt the CP-Q into Turkish and evaluate the validity and reliability of the Turkish version (CPQ-TR). Cross-sectional data were collected from 271 healthy adults aged 19–64 years, and a randomly selected subgroup (n = 40) completed a two-week reassessment and a 3-day dietary assessment. In a bilingual group (n = 18), ICC values for non-categorical items ranged from 0.57 to 0.97, indicating moderate-to-excellent cross-language agreement. Known-groups analyses yielded the expected chronotype-related differences in nutrition timing, including later wake and eating event times and a wider work/school day eating window in evening types (p < 0.01), consistent with construct validity. Night Eating Questionnaire scores correlated with last eating event timing (r = 0.59–0.69) and night eating frequency (r = 0.55) (p < 0.01), supporting convergent validity. CPQ-TR timing variables correlated strongly with dietary-record-derived meal timings (r = 0.92–0.97; p < 0.01), whereas agreement for the largest meal of the day was low (κ = 0.12, p = 0.27). Test–retest analyses showed good-to-excellent temporal stability (ICC = 0.86–0.98). In conclusion, the CPQ-TR showed generally favorable validity and reliability findings for timing-related variables in this sample, whereas the largest-meal item should be interpreted cautiously.