Circadian Administrator

Circadian Administrator

Nearly 20% of the workforce worldwide work at times outside of 7 AM - 6 PM due to evening shifts, night shifts, or rotating shifts.1

Shift work has been connected to a higher prevalence in obesity, diabetes, metabolic disturbances, and cardiovascular morbidity.2

The increased health problems related to shift work are thought to be at least partially due to circadian misalignment that results in reduced insulin sensitivity, poorer glucose regulation and altered patterns of leptin and cortisol secretion.3

Sleep deprivation is also thought to be a contributor to the increased health problems seen among shift work populations, as shift workers often report greater sleep difficulties and reduced sleep quantity as compared to typical daytime employees.4 It's been well documented that sleep deprivation is an independent risk factor for many of the health detriments associated with shift work.5

Recent research has investigated the impact of delayed timing of eating on weight and metabolism. In a recent review of the evidence to date, scientists make a strong case that delayed timing of eating could be a contributing factor to weight gain and metabolic dysregulation.6

Weight Gain & Timing of Eating - Research Findings

Research on the impact of delayed timing of eating on weight and metabolism has provided the following insights:

- Delays in the typical daytime pattern of eating has been found to increase the risk of obesity and metabolic syndrome in humans.2,7

- Delayed sleep timing is associated with poorer diet and later eating times, the latter of which is related to higher BMI.8

- Evening type (owls) chronotype, as compared to the morning type (lark), has also been found to be associated with larger meals, later eating times, and higher BMI.9-11

- Descriptive studies of non-eating disordered adults found that breakfast intake was negatively related to total daily caloric intake and weight gain, 12,13 while the proportion of food consumed late at night was positively related to total energy intake.14

- One study found that distributing the majority of meals to the morning for 6 weeks resulted in greater weight loss compared to distributing the majority of meals to the afternoon and evening for 6 weeks.15

- Another study found that "late eaters" (those eating their large, mid-day meal after 3 PM), as compared to "early eaters" (eating their mid-day meal before 3 PM), lost significantly less weight during the 5-month study, despite similar self-reported energy intake, macronutrient content, estimated energy expenditure, appetitive hormone profiles, and self-reported sleep duration.16


Results from various studies collectively suggest that nighttime eating may contribute to weight gain, or, at a minimum, maintenance of increased weight.6

Based on this body of research, behavioral modification strategies that might promote weight loss or prevent weight gain include:

- Eating lunch earlier in the daytime 16

- Eliminating eating in the evening after 7-8 PM 8,17

- Avoiding sleep restriction when dieting 18

- Advancing bedtime 8

Implications for Shift Workers

While these new behavioral modification strategies are promising to individuals operating within a typical circadian rhythm, shift workers can face various challenges when implementing these strategies.

Given the unique challenges that shift workers face, health strategies such as timing of eating must be modified to best fit one’s schedule.

Shiftwork Lifestyle Training

Adjusting to a shiftwork lifestyle isn’t intuitive, and most shiftworkers don’t know how to adjust their lifestyle to minimize the negative effects of working around the clock. As a result, workers’ job performance, safety, health, and family life can suffer as company profits and productivity fall.

Training workers on how to manage a shiftwork lifestyle is a powerful tool for improving your employees’ physical and psychological well-being, thereby increasing morale and effectiveness, while potentially reducing health care costs.

CIRCADIAN® Managing a Shiftwork Lifestyle Training

Working closely with researchers and experienced shiftworkers, CIRCADIAN has developed the Managing a Shiftwork Lifestyle training program to provide practical solutions for easing the adjustment and day-to-day difficulties associated with shiftwork lifestyles.

Download our complementary CIRCADIAN® white paper, “Shiftwork Lifestyle Training: Employee and Employer Benefits”.




CIRCADIAN® is the global leader in providing 24/7 workforce performance and safety solutions for businesses that operate around the clock. Through a unique combination of consulting expertise, research and technology, software tools and informative publications, CIRCADIAN helps organizations in the 24-hour economy optimize employee performance and reduce the inherent risks and costs of their extended hours operations.


1. Wright Jr KP, Bogan RK, Wyatt JK. Shift work and the assessment and management of shift work disorder (SWD). Sleep Med Rev. (2013): 17:41–54.

2. Åkerstedt T, Wright KP. Sleep loss and fatigue in shift work and shift work disorder. Sleep Med Clin. (2009): 4:257–71.

3. Scheer FA, Hilton MF, Mantzoros CS, Shea SA. Adverse metabolic and cardiovascular consequences of circadian misalignment. Proc Natl Acad Sci U S A. (2009): 106:4453–8.

4. Åkerstedt, Torbjörn. "Shift work and disturbed sleep/wakefulness." Occupational Medicine 53.2 (2003): 89-94.

5. Mullington, Janet M., et al. "Cardiovascular, inflammatory, and metabolic consequences of sleep deprivation." Progress in cardiovascular diseases 51.4 (2009): 294-302.

6. Allison, Kelly C., Namni Goel, and Rexford S. Ahima. "Delayed timing of eating: impact on weight and metabolism." Current Obesity Reports 3.1 (2014): 91-100.

7. Maury E, Ramsey KM, Bass J. Circadian rhythms and metabolic syndrome: from experimental genetics to human disease. Circ Res. (2010): 106:447–62.

8. Baron KG, Reid KJ, Kern AS, Zee PC. Role of sleep timing in caloric intake and BMI. Obesity. (2011): 19:1374–81.

9. Lucassen EA, Zhao X, Rother KI, Mattingly MS, Courville AB, de Jonge L, et al. Evening chronotype is associated with changes in eating behavior, more sleep apnea, and increased stress hormones in short sleeping obese individuals. PLoS One. (2013): 8:e56519.

10. Kanerva N, Kronholm E, Partonen T, Ovaskainen ML, Kaartinen NE, Konttinen H, et al. Tendency toward eveningness is associated with unhealthy dietary habits. Chronobiol Int. (2012): 29:920–7.

11. Culnan E, Kloss JD, Grandner M. A prospective study of weight gain associated with chronotype among college freshmen. Chronobiol Int. (2013): 30:682–90.

12. De Castro JM. The time of day of food intake influences overall intake in humans. J Nutr. (2004): 134:104–11.

13. Van der Heijden AA, Hu FB, Rimm EB, van Dam RM. A prospective study of breakfast consumption and weight gain among U.S. men. Obesity. (2007): 15:2463–9.

14. Morse SA, Ciechanowski PS, Katon WJ, Hirsch IB. Isn’t this just bedtime snacking? The potential adverse effects of night-eating symptoms on treatment adherence outcomes in patients with diabetes. Diabetes Care. (2006): 29:1800–04.

15. Keim NL, Van Loan MD, Horn WF, Barbieri TF, Mayclin PL. Weight loss is greater with consumption of large morning meals and fat-free mass is preserved with large evening meals in women on a controlled weight reduction regimen. J Nutr. (1997): 127:75–82.

16. Garaulet M, Gómez-Abellán P, Alburquerque-Béjar JJ, Lee YC, Ordovás JM, Scheer FA. Timing of food intake predicts weight loss effectiveness. Int J Obes. (2013): 37:604–11.

17. LeCheminant JD, Christenson E, Bailey BW, Tucker LA. Restricting night-time eating reduces daily energy intake in healthy young men: a short-term cross-over study. Br J Nutr. (2013): 23:1–6.

18. Nedeltcheva AV, Kilkus JM, Imperial J, Schoeller DA, Penev PD. Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med. (2010): 153:435–41.

Thursday, 01 March 2012 18:48


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Stoneham, MA, 02180, USA