Shift workers' perceptions and experiences of adhering to a nutrition intervention at night whilst working: a qualitative study.

This study explored the feasibility of implementing a meal timing intervention during night shift work. Data were collected via semi-structured interviews. Interviews were coded inductively by two researchers independently, then three major themes were collaboratively developed. Subthemes from each major theme were mapped to the theoretical domains framework and the Capability Opportunity Motivation model of behaviour change. Seventeen night shift workers (rotating or permanent) aged between 25 and 65 years were interviewed. Participants predominately worked as health professionals. The feasibility of a simple meal timing intervention to avoid eating between 1 and 6 am on night shift is largely affected by three major influences (1) physical and emotional burden of shift work which drives food temptations; (2) the workplace context including the meal break environment, social and cultural context at work, and break scheduling; and (3) motivation of the individual. Facilitators to avoiding eating at night were, keeping busy, having co-worker support, management support, education of health benefits and/or belief that the intervention was health promoting. The barriers to avoiding eating at night were the emotional and physical toll of working at night leading to comfort eating and not having rest areas away from food environments. To support night shift workers with changing timing of meals, interventions at work should target both individual and organisational level behaviour change.

The Impact of Meal Timing on Risk of Weight Gain and Development of Obesity: a Review of the Current Evidence and Opportunities for Dietary Intervention.

PURPOSE OF REVIEW: The aim of this short review is to provide an updated commentary on the current literature examining the impact of meal timing on obesity and weight gain in adults. The potential mechanisms, including novel and emerging factors, behind timing of food intake across the 24-h period in the development of obesity, and dietary strategies manipulating meal timing to ameliorate weight gain are also explored. RECENT FINDINGS: Dietary patterns that feature meal timing outside of the regular daytime hours can contribute to circadian disruption as food is metabolised in opposition to internal daily rhythms and can feedback on the timekeeping mechanisms setting these rhythms. Epidemiological evidence examining the impact of late meal timing patterns is beginning to suggest that eating at night increases the risk of weight gain over time. Mechanisms contributing to this include changes to the efficiency of metabolism across the day, and dysregulation of appetite hormone and gut microbiota by mis-timed meals. When meals are eaten, in relation to the time of day, is increasingly considered of importance when implementing dietary change in order to address the growing burden of obesity, although further research is required in order to determine optimal patterns.

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).

Multivariate selection mediated by aridity predicts divergence of drought-resistant traits along natural aridity gradients of an invasive weed.

Geographical variation in the environment underpins selection for local adaptation and evolutionary divergence among populations. Because many environmental conditions vary across species' ranges, identifying the specific environmental variables underlying local adaptation is profoundly challenging. We tested whether natural selection mediated by aridity predicts clinal divergence among invasive populations of capeweed (Arctotheca calendula) that established and spread across southern Australia during the last two centuries. Using common garden experiments with two environmental treatments (wet and dry) that mimic aridity conditions across capeweed's invasive range, we estimated clinal divergence and effects of aridity on fitness and multivariate phenotypic selection in populations sampled along aridity gradients in Australia. We show that: (1) capeweed populations have relatively high fitness in aridity environments similar to their sampling locations; (2) the magnitude and direction of selection strongly differs between wet and dry treatments, with drought stress increasing the strength of selection; and (3) differences in directional selection between wet and dry treatments predict patterns of clinal divergence across the aridity gradient, particularly for traits affecting biomass, flowering phenology and putative antioxidant expression. Our results suggest that aridity-mediated selection contributes to trait diversification among invasive capeweed populations, possibly facilitating the expansion of capeweed across southern Australia.

Does rearranging meal times at night improve cardiovascular risk factors? An Australian pilot randomised trial in night shift workers.

BACKGROUND AND AIMS: Shift workers face an increased risk of cardiovascular disease (CVD), type-2 diabetes and obesity. Eating during the night is a likely contributing factor, as it coincides with the time at which postprandial metabolism is least efficient. In this pilot randomised crossover trial, we examine the effects of a short overnight fast on CVD risk markers (primarily postprandial triglyceride and glucose response) of night shift workers. METHODS AND RESULTS: Night shift workers with abdominal obesity underwent 4-week intervention and control periods, separated by ≥ 2 weeks washout. In the intervention period, an overnight fast (0100 h-0600 h) was implemented, by redistributing 24-h energy intake. Usual dietary habits were followed in the control period. Outcomes between intervention and control were compared using mixed effects linear regression models. Nineteen adults completed the trial [13 females, mean (±SD) age 41 ± 10 years, BMI 30.7 ± 5.7 kg/m2]. Postprandial triglyceride and glucose response post intervention were not different to post control. The overnight fast was well-tolerated by participants with an adherence rate of 95%, assessed by weekly 24-h dietary recalls. Exploratory analysis indicates lower mean body weight post intervention compared to post control (mean difference: -0.9 kg, 95% CI: -1.3 to -0.4). CONCLUSIONS: Night shift workers who habitually ate during their night shifts were able to rearrange their meal times to maintain a small overnight fast, which may have promoted small weight changes. This warrants further investigation into the role of meal timing in mitigating the metabolic consequences of night shift work. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (http://anzctr.org.au/) registered on the 30th May 2017 (ACTRN12617000791336).

Diurnal variation in gene expression of human peripheral blood mononuclear cells after eating a standard meal compared with a high protein meal: A cross-over study.

BACKGROUND & AIMS: Eating at night has been linked to impaired glucose metabolism and dyslipidaemia that is likely a consequence of an underlying disrupted circadian rhythm in metabolic processes. The aim of this study was to explore the gene expression differences after eating a standard test meal or high protein test meal at night compared with the same meal in the morning. METHODS: In a cross over design, 10 healthy adults fasted for >10 h and then completed four acute meal challenges at 8am and 8pm on non-consecutive days separated by a wash out, consuming either a high protein low carbohydrate test meal or an isocaloric standard protein and carbohydrate test meal. Fasting and two-hour postprandial blood samples were collected to measure gene expression. For a subset of five participants RNA sequencing was completed on the Illumina NextSeq500. RESULTS: The time of day a meal is consumed had an effect on which genes were differentially regulated in the acute postprandial period, with only 6.5% of differentially expressed genes the same both morning and night. More genes were involved in lipid metabolic pathways in the morning and immune pathways at night. RTqPCR analysis of target genes suggested that key regulatory genes responsible for nutrient sensing and lipid and glucose metabolism are differentially expressed at night. These may play a role in improved blood glucose control in peripheral tissues that is observed after eating in the morning but to a lesser extent or not at all at night. Modulation of the macronutrient composition of a meal led to changes in expression of genes involved in the circadian clock and metabolism. CONCLUSIONS: Investigating the differences in the transcriptomic response to food at night provides a greater understanding of the mechanisms underlying the changing metabolic phenotypes, characterised by circulating metabolic biomarkers, according to the time of day.

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.

Glycaemic response at night is improved after eating a high protein meal compared with a standard meal: A cross-over study.

BACKGROUND & AIMS: Eating at night, compared to day-time, results in a relative hyperglycaemia contributing to an increased risk of Type 2 diabetes for those who habitually eat at night, such as shift workers. Meal choice at night can adversely impact postprandial glycaemia. Meals high in protein have the capacity to favourably reduce night time perturbations in glucose. The aim of this study was to examine if a high protein meal attenuates postprandial glucose at night, compared with a standard protein meal. METHODS: In a 2 × 2 factor cross over design, healthy adults completed four acute meal challenges. Test meals were consumed at 8am and 8pm on separate occasions; a high protein (HP) meal (41% of energy from protein, 29% from carbohydrates) or isocaloric standard meal (15% from protein, 46% from carbohydrate). Bloods were sampled at fasting and for three hours postprandially and incremental area under the curve (iAUC) determined using the trapezoid rule. Freidman's test was conducted prior to post hoc Wilcoxon sign test, and significance set at p < 0.0083 after Bonferroni correction. RESULTS: Plasma glucose median (IQR) iAUC after the HP meal was similar to the standard meal when consumed in the morning (12.9 (19.9) vs. 36.4 (99.6)mmol/L.3 h, p = 0.028). The HP meal elicited a significantly lower glucose iAUC (59.6 (117.0)mmol/L.3 h) compared to the standard meal (208.8 (154.1)mmol/L.3 h) when consumed at night (p = 0.005). No significant differences in insulin responses were found between test meals, at either time of day (p = 0.100). CONCLUSION: A HP meal is effective in attenuating the postprandial glucose excursion observed with night eating by 71.4%, compared to a meal with a macronutrient composition within dietary guidelines. If eating at night, reducing the carbohydrate content of a meal, and replacing this with protein, can result in a more favourable postprandial metabolic response. TRIAL REGISTRATION: Trial ID number: ACTRN12617000294358, Website of trial registry: http://www.anzctr.org.au/.

The Impact of Time of Day on Energy Expenditure: Implications for Long-Term Energy Balance.

There is evidence to indicate that the central biological clock (i.e., our endogenous circadian system) plays a role in physiological processes in the body that impact energy regulation and metabolism. Cross-sectional data suggest that energy consumption later in the day and during the night is associated with weight gain. These findings have led to speculation that when, as well as what, we eat may be important for maintaining energy balance. Emerging literature suggests that prioritising energy intake to earlier during the day may help with body weight maintenance. Evidence from tightly controlled acute experimental studies indicates a disparity in the body's ability to utilise (expend) energy equally across the day and night. Energy expenditure both at rest (resting metabolic rate) and after eating (thermic effect of food) is typically more efficient earlier during the day. In this review, we discuss the key evidence for a circadian pattern in energy utilisation and balance, which depends on meal timing. Whilst there is limited evidence that simply prioritising energy intake to earlier in the day is an effective strategy for weight loss, we highlight the potential benefits of considering the role of meal timing for improving metabolic health and energy balance. This review demonstrates that to advance our understanding of the contribution of the endogenous circadian system toward energy balance, targeted studies that utilise appropriate methodologies are required that focus on meal timing and frequency.

Temporal pattern of eating in night shift workers.

Understanding shift workers dietary intake patterns may inform interventions targeted at lowering chronic disease risk. This study examined the temporal distribution of food intake as shift workers rotate between night shifts, day shift and/or days off to identify differences in energy intake, eating frequency, and adherence to dietary guidelines by shift type (night shift vs. day). Night shift (NS) workers completed a four-day food diary that included a minimum of two night shifts and one-day shift (DS)/day off (DO), recording all food, beverages and time of consumption. Comparisons were between shift types, using ANOVA for continuous data and generalized estimating equations for count data, data reported as mean (SE). When comparing NS and DSDO, there were no differences in energy intake (24 h) (8853 (702) vs. 9041 (605) kJ, n = 22) or adherence to dietary guidelines. There was no difference between the number of eating occasions on NS and DSDO (5.6(0.3) vs 5.1(0.6) occasions) but less energy per eating occasion at night (1661(125) vs 1933(159) kJ). When working NS compared with DSDO there was higher total sugar (%E, 19.1(2.0) vs 15.0(2.4)) and lower saturated fat (%E, 13.8(1.2) vs 15.7(1.3)). Further, DSDO were characterized by a pattern of three main meals and a prolonged fasting period. It is important to determine if reducing eating occasions and providing opportunities for fasting improves metabolic health.

Effect of Night Time Eating on Postprandial Triglyceride Metabolism in Healthy Adults: A Systematic Literature Review.

Eating at night time, as is frequent in shift workers, may contribute to increased cardiovascular disease (CVD) risk through a disruption in usual lipid metabolism, resulting in repeated and sustained hyperlipidemia at night. This systematic review aimed to investigate the impact of eating a meal at night compared with the same meal eaten during the day on postprandial lipemia. Six databases were searched: CINAHL Plus, Cochrane Library, EMBASE, Ovid MEDLINE, Informit, and SCOPUS. Eligible studies were original research cross-over design with a minimum fasting period of 5 h before testing preceded by a standardized control meal; measured postprandial triacylglycerol (TAG) for 5 h or greater; had meal time between 0700 h and 1600 h for day time and between 2000 h and 0400 h for night time; and had within-study test meals (food or drink) that were identical in macronutrient composition and energy. Two authors independently completed eligibility and quality assessment using the American Dietetic Association Quality Criteria Checklist for Primary Research. After removing duplicates, 4,423 articles were screened, yielding 5 studies for qualitative synthesis. All studies identified at least one parameter of the postprandial TAG response that was different as a result of meal time (e.g., the total concentration or the time course kinetics). Two studies reported a greater total TAG concentration (area under curve) at night compared with day, and 3 studies found no difference. Four studies reported that the kinetics of the postprandial time course of TAGs was different at night compared with during the day. Inconsistent reporting in the primary studies was a limitation of the review. Night eating may negatively affect postprandial lipemia and this review shows there is a need to rigorously test this using standardized methods and analysis with larger sample sizes. This is critical for informing strategies to lower CVD risk for shift workers.

Does modifying the timing of meal intake improve cardiovascular risk factors? Protocol of an Australian pilot intervention in night shift workers with abdominal obesity.

INTRODUCTION: Shift work is an independent risk factor for cardiovascular disease (CVD). Shift workers who are awake overnight and sleep during the day are misaligned with their body's endogenous circadian rhythm. Eating at night contributes to this increased risk of CVD by forcing the body to actively break down and process nutrients at night. This pilot study aims to determine whether altering meal timing overnight, in a shift working population, will impact favourably on modifiable risk factors for CVD (postprandial bplasma lipids and glucose concentration). METHODS AND ANALYSIS: A randomised cross-over study with two 4-week test periods, separated by a minimum of a 2-week washout will be undertaken. The effectiveness of redistributing energy intake overnight versus ad libitum eating patterns on CVD risk factors will be examined in night shift workers (n=20), using a standard acute test meal challenge protocol. Primary outcomes (postprandial lipids and glucose) will be compared between the two conditions: post-intervention and post-control period using analysis of variance. Potential effect size estimates to inform sample size calculations for a main trial will also be generated. ETHICS AND DISSEMINATION: Ethics approval has been granted by the Monash University Human Research Ethics Committee (2017-8619-10329). Outcomes from this study will determine whether eliminating food intake for a defined period at night (1-6 am) impacts favourably on metabolic risk factors for CVD in night shift workers. Collective results from this novel trial will be disseminated through peer-reviewed journals, and national and international presentations. The results are essential to inform health promotion policies and guidelines for shift workers, especially those who aim to improve their metabolic health. TRIAL REGISTRATION NUMBER: ACTRN12617000791336; Pre-results.

An approach to assessing data quality in an area probability survey using CBPR.

Community-based participatory research (CBPR) approaches attempt to engage community members in all aspects of research conducted in the community. Proponents of CBPR suggest that among the many advantages to using CBPR is higher acceptance of and cooperation in research endeavors than is usually achieved through more traditional research approaches. Using secondary analysis of sample disposition data from two area probability surveys of the same community areas, one involving community interviewers in a fully collegial CBPR study and the other using professional interviewers, this study finds that data collected using CBPR techniques may lead to higher cooperation and lower refusal rates than data collected by professional interviewers. However, when compared to external population indicators such as census data, the sample produced by CBPR interviewers overrepresents certain population groups whereas the survey data produced by professional interviewers may underrepresent key population groups.

Introducing systems change in the schools: the case of school luncheons and vending machines.

A major public health crisis facing America's society is the increase in child and youth obesity, which has seen a fourfold increase in the last four decades. Major concerns include what children eat for school lunch and what other foods are available in schools. This paper illustrates efforts towards systems change in the luncheon program and food vending machines in the Chicago Public Schools. We discuss the different factors that lead to such changes using the framework of the social ecological model and the soft systems methodology, and we analyze how the resulting innovation was implemented and evaluated. First, we present a theoretical perspective to explain factors that influence children's eating patterns from a systems approach. Second, we discuss the antecedent factors that lead to systems change. Finally, we examine challenges to systems change, such as resistance to change, different stakeholder priorities, lack of resources, institutional bureaucracy, and unrealistic funder expectations.