Eating behaviours in night shift workers : a systematic review : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand

Abstract

Background: Globally, the increasing demand for 24–hour production and services has resulted in approximately 20% of the workforce in industrialised countries engaging in night shift work, either in a rotating or fixed shift schedule. Night work is associated with an increased risk of cardiometabolic diseases, including obesity, cardiovascular disease, and type 2 diabetes. This is partly due to an altered shift schedule causing circadian disruption and sleep loss, which can impair metabolic regulation, as well as changes in eating behaviours that may further contribute to these effects. Understanding these different eating behaviours will help inform the design of future interventions with the intention of mitigating these associated risks. Aim: To systematically review scientific literature and examine the broad range of eating behaviours experienced by night workers in both fixed and rotating schedules. Method: A comprehensive literature search was conducted using PubMed, Scopus and Discover (an aggregated host database that indexes Medline, Academic Search Premier, CINAHL and APA PsycINFO), to identify quantitative evidence. A total of 1468 studies were retrieved, and after the screening process, 22 studies were included in the review. A narrative synthesis was then conducted to summarise eating behaviours across four domains: what night workers are eating, when they are eating, where they are eating, and why they are deciding to eat, with comparison made with day workers on rotating or fixed shift schedules. Results: Overall diet quality was poor, with increased intakes of saturated fats, sugar and sodium exceeding recommended levels, and dietary fibre remaining below daily recommendations. The average 24-h energy intake did not differ between day and night shifts within rotational schedules. However, night shift workers exhibited irregular meal timing, increased snacking/eating at night, and higher consumption of discretionary food compared with day shift workers. Conclusion: The results of this review suggest that the impact of circadian disruption in addition to unhealthy eating behaviours may contribute to the relationship between night work and chronic metabolic diseases.