Eating on the night shift: A need for evidence‐based dietary guidelines?

The effects of shift work on sleep quality, diet quality, and obesity-related factors: A male population study

Recent studies suggest that shift working may trigger health issues through disrupted circadian rhythms and altered eating habits. This study aimed to examine the possible associations of shift work with sleep quality, diet quality and obesity-related parameters. This study was conducted with 150 males (75 shift and daytime workers) aged 24-50 years. Dietary intake was determined using the 24-hour recall method, and dietary quality was evaluated using the Healthy Eating Index-2010 (HEI-2010). Anthropometrical measurements and body composition were assessed. The Pittsburgh Sleep Quality Index was used to evaluate sleep quality. Fasting and postprandial glucose and insulin, and fasting lipid levels were analyzed. HOMA-IR was calculated, and blood pressure was measured. The total HEI-2010 score of shift workers (52.6 [45.4-58.8]) was lower than the daytime workers (55.9 [49.1-64.9]) (p = 0.016). Among individuals with good sleep quality, the total HEI-2010 score, seafood and plant proteins, fatty acids, and sodium scores were lower in shift workers compared to others (p < 0.05 for each). Non-obese shift workers had higher body weight, waist circumference, waist/hip ratio, VLDL-cholesterol, triglyceride, postprandial glucose, and insulin levels compared to daytime workers (p < 0.05 for each). This study demonstrates that shift working is associated with lower diet quality independent of sleep quality.

Understanding perceptions about the health effects of night working and the barriers and enablers to taking part in nutritional research: A qualitative study among night workers in England

Working at night is associated with adverse cardiometabolic health outcomes. However, there are a lack of nutritional intervention studies conducted amongst night workers, subsequently contributing to a lack of evidence-based guidelines for night workers. The aim of The Eating on the Night Shift study was to understand how night shift workers view working at night in relation to nutritional health and wellbeing, the barriers and enablers to participate in research and what kind of guidance would be useful to them. Semi-structured qualitative interviews were conducted with a convenience sample (n = 18) of night workers based in England. The interview covered experiences of working night shifts, perceptions about night work and their health, and perceptions of and likely engagement with nutritional research. Interviews were audio recorded and transcribed verbatim. Transcripts were coded using an inductive thematic analysis approach. Of the final sample 13 were female (72%), 39% worked a rotating shift pattern and 78% had worked night shifts for 1 year or more. Four overarching themes were identified: (1) the consequences of night work on health and wellbeing, (2) eating at night means a less healthy diet, (3) working at night has wider knock-on effects on aspects of lifestyle and wellbeing and (4) nutritional research is perceived as important, but there are barriers to participation. Night workers are aware that working at night can negatively impact their diet as well as their health. Nutritional researchers need to engage with night workers when considering intervention design and implementation as well as in the development of any resultant evidence-based guidance to ensure its relevance.

Developing an intervention to support dietary change for shift workers living with type 2 diabetes: A stakeholder consultation

BACKGROUND

Shift workers, compared to day workers, are more likely to be diagnosed with type 2 diabetes (T2D). Currently, there is no tailored programme of dietary support available to either shift workers living with T2D or employers.

METHODS

An intervention development consultation workshop was convened in June 2023 with the aim of evaluating potential interventions to identify those with a potential to take forward for further development. Findings from prior formative research into factors influencing dietary behaviour in shift workers with T2D were mapped to potential interventions addressing the barriers and enablers to healthy eating reported by shift workers with T2D. The findings of the Shift-Diabetes Study were presented in the context of the COM-B (Capability, Opportunity, Motivation, Behaviour) theoretical framework of behaviour change. Three interventions in turn were presented to attendees: (1) Educational resources and structured education, (2) Increasing availability and accessibility of food on a night shift and (3) Biofeedback and tailored advice. Seven workshop attendees were invited to express their thoughts, using the APEASE criteria (Affordability, Practicability, Effectiveness, Acceptability, Side-effects/Safety, Equity) to guide the discussion. The workshop was conducted online and recorded, and transcripts were thematically coded to the APEASE framework.

RESULTS/CONCLUSIONS

The workshop highlighted the importance of multilevel interventions to support dietary behaviour change in this occupational group. Priority actions identified include (i) understanding barriers to 24/7 food availability, (ii) including shift workers in clinical diabetes studies and (iii) research to understand the effectiveness of continuous glucose monitoring in shift workers with T2D.

Considering the impact of shift working on health

Shift work is necessary for the provision of health services, especially in hospitals as it is the only way to provide continuous care to patients. Working at night is inconsistent with the body's biological clock and night shift working hugely disrupts the circadian and sleep wake cycles. In 2020, the World Health Organization classified night shift working as being a 'probable' class 2A carcinogen and a number of independent cohort studies of both night workers and shift workers have observed increased incidence of certain cancers. Altered sleep timing, food timing and light exposure typical for shift workers leads to an acute circadian disruption and misalignment of regulatory hormones. This straying from synchronisation has been shown to result in individuals being more vulnerable to a number of chronic health conditions. Night shift work disrupts the normal sleep-wake cycle, often leading to shortened sleep duration and excessive fatigue and the results of this are far reaching. This article will explore the full impact of shift working, questioning if current practices employed within the NHS should continue.

Evaluation of the "Shifting Weight using Intermittent Fasting in night-shift workers" weight loss interventions: a mixed-methods protocol

Introduction

Shift workers are at a greater risk for obesity-related conditions. The impacts of working at night presents a challenge for designing effective dietary weight-loss interventions for this population group. The Shifting Weight using Intermittent Fasting in night-shift workers (SWIFt) study is a world-first, randomized controlled trial that compares three weight-loss interventions. While the trial will evaluate the effectiveness of weight-loss outcomes, this mixed-methods evaluation aims to explore for who weight-loss outcomes are achieved and what factors (intervention features, individual, social, organisational and wider environmental) contribute to this.

Methods

A convergent, mixed-methods evaluation design was chosen where quantitative and qualitative data collection occurs concurrently, analyzed separately, and converged in a final synthesis. Quantitative measures include participant engagement assessed via: dietary consult attendance, fulfillment of dietary goals, dietary energy intake, adherence to self-monitoring, and rates for participant drop-out; analyzed for frequency and proportions. Regression models will determine associations between engagement measures, participant characteristics (sex, age, ethnicity, occupation, shift type, night-shifts per week, years in night shift), intervention group, and weight change. Qualitative measures include semi-structured interviews with participants at baseline, 24-weeks, and 18-months, and fortnightly audio-diaries during the 24-week intervention. Interviews/diaries will be transcribed verbatim and analyzed using five-step thematic framework analysis in NVivo. Results from the quantitative and qualitative data will be integrated via table and narrative form to interrogate the validity of conclusions.

Discussion

The SWIFt study is a world-first trial that compares the effectiveness of three weight-loss interventions for night shift workers. This mixed-methods evaluation aims to further explore the effectiveness of the interventions. The evaluation will determine for who the SWIFt interventions work best for, what intervention features are important, and what external factors need to be addressed to strengthen an approach. The findings will be useful for tailoring future scalability of dietary weight-loss interventions for night-shift workers.Clinical trial registration: This evaluation is based on the SWIFt trial registered with the Australian New Zealand Clinical Trials Registry [ACTRN 12619001035112].

Dietary Patterns under the Influence of Rotational Shift Work Schedules: A Systematic Review and Meta-Analysis

Workers employed in rotating shift schedules are at a higher metabolic risk compared with those in regular day and fixed shift schedules; however, the contribution of diet is unclear. This systematic review aimed to investigate how rotating shift work schedules affect dietary energy intake and dietary patterns compared with regular day and fixed shift schedules. In addition, intraperson energy intake and dietary pattern comparisons within rotating shift schedules were investigated. Database searches were conducted on MEDLINE, Cochrane, CINAHL, PSYCinfo, EMBASE, and Scopus, in addition to manual search of bibliographic references, to identify articles. Two separate meta-analyses compared dietary intake between day work and rotating shift work schedules and within the rotational shift work group (morning/day and night shifts). Differences in dietary patterns were synthesized narratively. Thirty-one studies (n = 18,196 participants) were included in the review, and meta-analyses were conducted with 24-hour mean energy intake data from 18 (n = 16,633 participants) and 7 (n = 327 participants) studies, respectively. The average 24-hour energy intake of rotating shift workers was significantly higher than that of workers in regular daytime schedules [weighted mean difference (WMD): 264 kJ; 95% confidence interval (CI): 70, 458 kJ; P < 0.008; I2 = 63%]. However, the mean difference in 24-hour energy intake between morning/day shifts compared with night shifts within rotational shift schedules was not statistically significant (WMD: 101 kJ; 95% CI: -651, 852 kJ; P = 0.79; I2 = 77%). Dietary patterns of rotating shift workers were different from those of day workers, showing irregular and more frequent meals, increased snacking/eating at night, consumption of fewer core foods, and more discretionary foods. This review highlights that dietary intake in rotational shift workers is potentially higher in calories and features different eating patterns as a consequence of rotating shift work schedules. This review was registered at PROSPERO as ID 182507.

The emerging importance of tackling sleep-diet interactions in lifestyle interventions for weight management

Sleep habits are directly related to risk of obesity, and this relationship may be partly mediated through food choices and eating behaviour. Short sleep duration, impaired sleep quality and suboptimal sleep timing are all implicated in weight gain and adverse cardiometabolic health, at least partly mediated through their associations with diet quality. Short-term sleep restriction leads to increased energy intake, and habitually short sleepers report dietary intakes that indicate a less healthy diet compared with adequate sleepers. Evidence is emerging that sleep extension interventions in short sleepers may reduce intake of sugars and overall energy intake. Poor sleep quality, night shift work patterns and social jetlag are also associated with lower diet quality and consumption of energy-dense foods. Incorporating sleep advice into weight management interventions may be more effective than energy-restricted diets and exercise advice alone. However, there are a lack of intervention studies that aim to lengthen sleep, improve sleep quality or adjust irregular sleep timing to investigate the impact on dietary intakes and eating behaviour in participants aiming to lose weight or maintain weight loss. Finally, future research should take account of individual characteristics such as age, sex, life stage and changing working practices when designing combined lifestyle interventions including sleep behaviour change for health and well-being.