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This thesis investigates meal strategies to improve metabolism at night. It finds that changing the nutrient composition of a meal at night can improve post meal blood sugar levels, and established that the timing of food influences which genes are expressed in response to eating.

Supplemental material, SupplementaryTable1 for Effect of Night Time Eating on Postprandial Triglyceride Metabolism in Healthy Adults: A Systematic Literature Review by Maxine P. Bonham, Elleni Kaias, Iona Zimberg, Gloria K. W. Leung, Rochelle Davis, Tracey L. Sletten, Hazel Windsor-Aubrey and Catherine E. Huggins in Journal of Biological Rhythms

Building effective policy advocacy campaigns, creating programs that support sustainable systemic changes, and engaging parents to identify and advocate for critical issues are all key to supporting healthy schools and communities., Stanford Social Innovation Review, 17(3), A6-A8

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. An understanding of the mechanisms causing metabolic disruption after eating at night is important for prevention and management of disease risk factors. The aim of this study was to explore the transcriptomic differences in nutrient metabolism after eating a meal at night compared with the same meal in the morning. In a cross over design, 10 healthy adults fasted for >10 hours and then completed two acute meal challenges at 8am and 8pm on non-consecutive days separated by a wash out. Fasting and postprandial blood samples were collected to assess glucose and insulin responses. For a subset of five participants RNA sequencing was completed on the Illumina NextSeq500. Total RNA was extracted from peripheral blood mononuclear cells at fasting (baseline) and 2 h after the test meal, the quality of all samples was above RIN 8 (AATI Fragment Analyzer). Differential expression analysis was completed using the DESeq2 package. False discovery rate correction was applied at the pathway analysis level, conducted in PathVisio. Postprandial blood glucose was significantly higher at 8pm vs. 8am (208.8(154.1)mmol/L.3hr vs 36.4(99.6)mmol/L.3hr, p = 0.005) no concurrent changes in insulin responses were observed (p = 0.100). Under fasting conditions, 704 genes were differentially expressed between morning and night, with 60% of these genes being down regulated at night. The meal challenges were associated with changes in gene expression. Compared with fasting, in the morning 552 genes were differentially expressed, and 532 genes were differentially expressed in the evening, however only 7% were commonly differentially regulated at both times of day. Pathway analysis of the differentially expressed genes identified that more immune system and signal transduction pathways were enriched after eating at night compared with morning, where as a greater number of pathways involved in lipid metabolism were enriched in the morning. The time of day a meal is consumed has an effect on which genes are differentially regulated in the acute postprandial period, and the biological pathways they are involved in. Investigating the differences in the transcriptomic response to food at night provides a greater understanding of the mechanisms underlying the phenotypic dissimilarities observed in circulating metabolic biomarkers according to the time of day.

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. Summary 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.

IntroductionShift 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 analysisA 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 disseminationThe 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 numberAustralian New Zealand Clinical Trials Registry (ACTRN-12619001035112).

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. Refereed/Peer-reviewed

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. Refereed/Peer-reviewed