Exploring Australian night shift workers' food experiences within and outside of the workplace: a qualitative photovoice study.

OBJECTIVE: Night shift workers are at a 20 to 40 % increased risk of metabolic diseases, which may be associated with their disrupted eating patterns. This qualitative study explores factors that influence night shift workers' eating habits, within and outside of the workplace, to identify target areas for health promotion strategies. PARTICIPANTS AND SETTING: Eligible participants resided in Australia, working at least three overnight shifts per month. DESIGN: The photovoice method was used, whereby participants were asked to take photos that represent their typical eating habits. These photos were incorporated as prompts in a semi-structured interview, which explored factors influencing eating habits on night shifts and days-off and perceptions and enablers to healthy eating. RESULTS: Ten participants completed the study. Thematic analysis generated four main themes, which were mapped onto the Social Ecological Model (SE Model). Aligned with the SE Model, our results show night shift workers' eating habits are influenced by intrapersonal, interpersonal and (work) organisational levels. Participants reported that at work, appropriate food preparation facilities are required to enable healthy food choices. Poor shift work rostering leads to prolonged fatigue on days-off, limiting their ability and motivation to engage in healthy eating. Consequently, night shift workers seem to require additional supports from their social networks and enhanced food literacy skills, in order to adopt/ maintain healthy eating behaviours. CONCLUSIONS: Night shift work creates individual and environmental barriers to healthy eating, which are present during and outside of work. Health promotion strategies for this population should include multiple approaches to address these barriers.

Study protocol for the Shifting Weight using Intermittent Fasting in night shift workers (SWIFt) study: a three-arm randomised controlled trial comparing three weight loss strategies in night shift workers with obesity.

INTRODUCTION: Shift workers are at an increased risk of developing obesity and type 2 diabetes. Eating and sleeping out of synchronisation with endogenous circadian rhythms causes weight gain, hyperglycaemia and insulin resistance. Interventions that promote weight loss and reduce the metabolic consequences of eating at night are needed for night shift workers. The aim of this study is to examine the effects of three weight loss strategies on weight loss and insulin resistance (HOMA-IR) in night shift workers. METHODS AND ANALYSIS: A multisite 18-month, three-arm randomised controlled trial comparing three weight loss strategies; continuous energy restriction; and two intermittent fasting strategies whereby participants will fast for 2 days per week (5:2); either during the day (5:2D) or during the night shift (5:2N). Participants will be randomised to a weight loss strategy for 24 weeks (weight loss phase) and followed up 12 months later (maintenance phase). The primary outcomes are weight loss and a change in HOMA-IR. Secondary outcomes include changes in glucose, insulin, blood lipids, body composition, waist circumference, physical activity and quality of life. Assessments will be conducted at baseline, 24 weeks (primary endpoint) and 18 months (12-month follow-up). The intervention will be delivered by research dietitians via a combination of face-to-face and telehealth consultations. Mixed-effect models will be used to identify changes in dependent outcomes (weight and HOMA-IR) with predictor variables of outcomes of group, time and group-time interaction, following an intention-to-treat approach. ETHICS AND DISSEMINATION: The study protocol was approved by Monash Health Human Research Ethics Committee (RES 19-0000-462A) and registered with Monash University Human Research Ethics Committee. Ethical approval has also been obtained from the University of South Australia (HREC ID: 202379) and Ambulance Victoria Research Committee (R19-037). Results from this trial will be disseminated via conference presentations, peer-reviewed journals and student theses. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry (ACTRN-12619001035112).

Effects of macronutrient manipulation on postprandial metabolic responses in overweight males with high fasting lipids during simulated shift work: A randomized crossover trial.

BACKGROUND & AIMS: Meals consumed out of synchronisation with normal circadian rhythms are associated with metabolic dysregulation. Changes in macronutrient composition of meals can improve metabolic responses during the day. Therefore, we aimed to investigate whether macronutrient manipulation of meals alters postprandial glucose and lipid responses and the expression of circadian genes during the night. METHODS: In a randomised crossover trial, 16 overweight males with high fasting lipids were fed isocaloric meals (2.7 MJ) at 0000 h. The meals differed primarily in total fat and total sugars content (control (8% total sugar, 5% saturated fat) vs test (16% total sugar, 26% saturated fat)). Postprandial blood samples were collected for glucose, insulin (3 h) and triglycerides (6 h) and analysed as incremental area under the curve (iAUC). RNA was extracted at 0 h, 2 h and 4 h and changes in expressions of the circadian genes clock and Per 1-3 analysed. RESULTS: Postprandial glucose (p = 0.04) and insulin iAUC (p = 0.02) were significantly higher after consumption of the test meal compared to the control meal. Postprandial triglyceride iAUC was not statistically different between the two meal types (p = 0.72). No change in circadian gene expression was observed after the two meals. CONCLUSIONS: Our results showed that macronutrient composition affects postprandial metabolic response at night. It emphasizes the need to consider the role and effects of night time eating, when developing metabolic disease prevention strategies for shift workers. STUDY ID NUMBER: ACTRN12618001115224. WEBSITE OF TRIAL REGISTRY: http://www.anzctr.org.au/. Retrospectively registered after data collection.