Normative values of the Three-Factor Eating Questionnaire -R18 in three Northern Finland cohort populations by sex and BMI classes.

The revised Three-Factor Eating Questionnaire -18 (TFEQ-R18) is used to assess eating behaviour in weight management, obesity, and epidemiological studies. We provided sex-specific normative values as percentiles for the TFEQ-R18 from three population-based samples (Northern Finland cohorts) across different age groups (i.e., 33-35, 45-46, and 68-70 years) among 8,959 participants (58% female). Mean values with SD were compared across six BMI classes, stratified by sex and age group. Percentile and mean values for cognitive restraint and emotional eating were higher in females than in males across all age groups. Additionally, the mean values for uncontrolled eating and emotional eating were highest in young adulthood and lowest in old adulthood, whereas cognitive restraint was higher in old adulthood than among younger adults. TFEQ-R18 domain scores differed between BMI classes; visual inspection suggested positive linear or slightly curvilinear associations in all age groups. These population-based norms may help healthcare professionals identify deviant eating behaviour and target support. Normative data also enhance the clinical and research utility of the TFEQ-R18. According to our findings, universal cut-off values cannot be defined for TFEQ-R18 scores; instead, the scores should be interpreted in relation to sex, age, and weight status. Future research should examine the longitudinal changes of eating behaviour in the general population and aim to find out cut-off scores for the screening of disordered eating. Also, the co-occurrence of eating behaviour dimensions in the general population and among obesity-treatment-seeking individuals needs to be recognised for the multidimensional manifestations of eating behaviour.