The effects of individual circadian rhythm differences on insomnia, impulsivity, and food addiction

Purpose: Individuals can generally be divided into morning, neither and evening types according to behavioral, psychological, and biological variables including appetite levels, usual meal times, sleep times, and melatonin secretion. These factors together identify a person as being part of a certain chronotype, i.e., as feeling more efficient either in the morning (morning type) or later in the day (evening type). Food addiction is defined as addictive behavior toward palatable foods and is thought to be one of the underlying risk factors for obesity. Our aim in this study was to investigate the relationship between circadian rhythm differences and food addiction via insomnia and impulsivity in university students. Method: Participants were 1323 university students, filled out a package of psychological tools, including the Morningness–Eveningness Questionnaire, Insomnia Severity Index, Barratt Impulsiveness Scale Short Form, and Yale Food Addiction Scale. Logistic regression analysis was used to investigate direct relation of food addiction with insomnia, impulsivity and obesity, and mediation regression analysis was used to investigate the indirect effect of circadian rhythm differences on food addiction. Results: Our findings indicated that evening types were more prone to insomnia and impulsivity, and also insomnia and impulsivity significantly contributed to the variance of food addiction. Although there was no significant linear relationship between circadian rhythm differences and food addiction, evening-type circadian preferences were indirectly associated with higher food addiction scores mediated by insomnia and impulsivity. Conclusion: The most remarkable result of our work was that circadian rhythm differences seem to indirectly effect on food addiction through elevated insomnia and impulsivity. Level of evidence: Level V, descriptive cross-sectional survey.