Is 24-hour energy intake greater during night shift compared to non-night shift patterns? A systematic review

ABSTRACT

Introduction: Epidemiological studies show that shift workers are at increased risk of cardiovascular diseases, metabolic dysfunction, diabetes, and obesity. Previous research has shown no difference in energy intake between night and day shifts only; however, it remains unclear whether other non-night shift patterns are different to night shift.

Objectives: We investigated whether energy intake of night-shift workers differed from other shift patterns using calorimetry, food diary or food recall over 24-hour periods.

Methods: A systematic review was conducted searching CINAHL, MEDLINE, Web of Science, Embase and PsycINFO databases for observational and interventional studies measuring energy intake in real or simulated shift work. Energy intake was extracted to compare night, day, afternoon/evening and rotating shift work cases.

Results: After duplicate removal, we screened 1057 abstracts and 68 full-text articles were assessed for eligibility of which 15 studies met the inclusion criteria. All studies were cross-sectional and case–control designs in shift workers. Risk of bias assessment showed a low to moderate risk of bias in the majority of studies. There was no difference in energy intake between night-shift work and non-night shift patterns including early morning, day and afternoon/evening shifts. Night-shift workers did not favor particular macronutrients in comparison to other shift schedules.

Conclusions: Energy and macronutrient intake were not detectably different in night shift compared to other shift patterns. Shift work patterns were heterogeneous which likely impacted on dietary assessment timings and computation of 24-h energy intake. Future studies should examine shift schedules with precise circadian timing of food consumption to determine if differences exist in energy and macronutrient intake between different shift patterns.

KEYWORDS:

• Calorie
• circadian
• day shift
• dietary patterns
• eating habits
• kilojoule
• macronutrient intake
• night shift
• night work

Acknowledgments

This review was partly funded through The University of Sydney Office of Global Engagement/Partnership Collaboration Awards.

Disclosure of interest

The authors listed have no conflicts of interest to disclose.

Author Contributions

EAC, NABE, VL, MC, CMH, NSM, CLP, JSCS, YLLG & CJG contributed to the design and implementation of the review, to the analysis of the results and to the writing of the manuscript.

Additional information

Funding

EAC & NSM receives funding through the National Health and Medical Research Council Center of Research Excellence, “NeuroSleep” Sydney, NSW, Australia. CLP receives funding through a National Health and Medical Research Council 570 Boosting Dementia Research Leadership Fellowship and the Sydney Medical School Foundation Chapman Fellowship. CMH receives funding through a National Health and Medical Research Council Australian Research Council Dementia Research Development Fellowship. MC receives 575 funding through The Sydney Research Excellence Initiative Q4 (SREI). National Health and Medical Research Council Centre for Clinical Research Excellence into Translational Sleep Neurobiology “NeuroSLEEP” (APP1060992)