Chronobiological traits predict the restrained, uncontrolled, and emotional eating behaviors of female university students.

Although significant associations between diurnal preference and restrained eating behaviors were previously reported, such reports are scarce and, in some respects, inconclusive. In this cross-sectional survey of 567 female university students aged between 17 and 23 years, we tried to clarify and extend the previous findings on chronobiological correlates of these behaviors. We administered the three-Factor-Eating-Questionnaire Revised and three questionnaires designed to assess trait-, ability-, and state-like differences in the domain of chronobiology, the Morningness-Eveningness Questionnaire (MEQ), the Sleep-Wake Pattern Assessment Questionnaire, and the Munich ChronoType Questionnaire, respectively. Statistical analyses included factor, correlation, and regression analyses. We found that any of three aspects of unhealthy eating behaviors (i.e., lack of cognitive eating restraint, uncontrolled eating, and emotional eating) was linked to one or more dimensions of individual chronobiological differences. We explained the previously reported inconclusive results by the differential relationship of two subconstructs of diurnal preferences to eating behaviors. For instance, such relationship was found for two (morning and evening) subscales of the MEQ. Cognitive eating restraint and uncontrolled eating were related to the morning subscale, while emotional eating was related to the evening subscale. These associations were supported by the associations revealed for morning vs. evening components of earliness-lateness assessed with two other questionnaires, (e.g., morning lateness and sleep offset vs. evening lateness and sleep onset, respectively). We conclude that unhealthy eating behaviors seem to be linked to unhealthy sleep-wake habits and behaviors and to inabilities to wake or sleep on demand at certain times of the day.