Association between chronotype, food intake and physical activity in medical residents

An individual's chronotype is a trait which reflects his/her diurnal preferences for the times of rest and activities, and displays a continuum from morningness to eveningness. Studies have shown that eveningness tends to be associated with a less healthy lifestyle, including increased likelihood of developing obesity. In this study, we examined the relationship between chronotype and food intake, physical sleep and activity in 72 resident physicians (52 women and 20 men). Assessments included chronotype evaluation by the Horne and Ostberg Morningness-Eveningness questionnaire (MEQ); food intake pattern through a self-administered food diary that was kept over the course of 3 non-successive days; physical activity level, using the Baecke questionnaire (BQ); sleep quality and quantity using the Pittsburgh Sleep Quality Index (PSQI); and sleepiness, Epworth Sleepiness Scale (ESS). Linear regression analyses, after adjustments for age, sex, body mass index (BMI), hours of additional work per week ESS and total physical activity score, showed that the chronotype score was negatively associated with cholesterol (coefficient = -0.24; p = 0.04), sweets (coefficient = -0.27, p = 0.03) and vegetables (coefficient = -0.26; p = 0.04) intakes. Following the same statistical adjustments, the chronotype score was positivity associated with leisure-time index (coefficient = 0.26, p = 0.03) and BQ total score (coefficient = 0.27, p = 0.03). We concluded that most issues related to nutrition problems and unhealthy lifestyle were associated with scores indicative of eveningness. These findings emphasize the importance of assessing an individual's chronotype when examining feeding behavior.