Stability of the timing of food intake at daily and monthly timescales in young adults

• Published in: Scientific reports 2020-11, Vol.10 (1), p.20849-20849, Article 20849
• Main Authors: McHill, Andrew W., Hilditch, Cassie J., Fischer, Dorothee, Czeisler, Charles A., Garaulet, Marta, Scheer, Frank A. J. L., Klerman, Elizabeth B.
• Format: Article
• Language: English
• Subjects: 631/378/1385; 692/499; 692/700/2814; Body composition; Calories; Circadian Rhythm - physiology; Circadian rhythms; College students; Correlation coefficient; Cross-Sectional Studies; Eating - physiology; Energy Intake - physiology; Feeding Behavior - physiology; Feeding Behavior - psychology; Female; Food; Food intake; Hospitals; Human factors research; Humanities and Social Sciences; Humans; Hypotheses; Laboratories; Male; Meals; Meals - psychology; Medicine; Melatonin; multidisciplinary; Obesity; Physiology; Public health; Science; Science (multidisciplinary); Sleep; Time Factors; Womens health; Young Adult; Young adults
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-77851-z

Cross-sectional observations have shown that the timing of eating may be important for health-related outcomes. Here we examined the stability of eating timing, using both clock hour and relative circadian time, across one semester (n = 14) at daily and monthly time-scales. At three time points ~ 1 month apart, circadian phase was determined during an overnight in-laboratory visit and eating was photographically recorded for one week to assess timing and composition. Day-to-day stability was measured using the Composite Phase Deviation (deviation from a perfectly regular pattern) and intraclass correlation coefficients (ICC) were used to determine individual stability across months (weekly average compared across months). Day-to-day clock timing of caloric events had poor stability within individuals (~ 3-h variation; ICC = 0.12–0.34). The timing of eating was stable across months (~ 1-h variation, ICCs ranging from 0.54–0.63), but less stable across months when measured relative to circadian timing (ICC = 0.33–0.41). Our findings suggest that though day-to-day variability in the timing of eating has poor stability, the timing of eating measured for a week is stable across months within individuals. This indicates two relevant timescales: a monthly timescale with more stability in eating timing than a daily timescale. Thus, a single day’s food documentation may not represent habitual (longer timescale) patterns.