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.

Unusual meal timing has been associated with a higher prevalence of chronic disease. Those at greater risk include shift workers and evening chronotypes. This study aimed to validate the content of a Chrononutrition Questionnaire for shift and non-shift workers to identify temporal patterns of eating in relation to chronotype. Content validity was determined using a Delphi study of three rounds. Experts rated the relevance of, and provided feedback on, 46 items across seven outcomes: meal regularity, times of first eating occasion, last eating occasion, largest meal, main meals/snacks, wake, and sleep, which were edited in response. Items with greater than 70% consensus of relevance were accepted. Rounds one, two, and three had 28, 26, and 24 experts, respectively. Across three rounds, no outcomes were irrelevant, but seven were merged into three for ease of usage, and two sections were added for experts to rate and comment on. In the final round, all but one of 29 items achieved greater than 70% consensus of relevance with no further changes. The Chrononutrition Questionnaire was deemed relevant to experts in circadian biology and chrononutrition, and could represent a convenient tool to assess temporal patterns of eating in relation to chronotype in future studies.

The world is becoming increasingly urbanised, impacting human interactions with natural environments (NEs). NEs take a number of forms, ranging from pristine, modified, to built NEs, which are common in many urban areas. NEs may include nature-based solutions, such as introducing nature elements and biological processes into cities that are used to solve problems created by urbanisation. Whilst urbanisation has negative impacts on human health, impacting mental and physical wellbeing through a number of mechanisms, exposure to NEs may improve human health and wellbeing. Here, we review the mechanisms by which health can be improved by exposure to NEs, as explained by Stress Reduction Theory, Attention Restoration Theory, and the ‘Old Friends’/biodiversity hypothesis. Such exposures may have physiological and immunological benefits, mediated through endocrine pathways and altered microbiota. Citizen Science, which often causes exposure to NEs and social activity, is being increasingly used to not only collect scientific data but also to engage individuals and communities. Despite being a named component of scientific and environmental strategies of governments, to our knowledge, the intrinsic health benefits of Citizen Science in NEs do not form part of public health policy. We contend that Citizen Science programs that facilitate exposure to NEs in urban areas may represent an important public health policy advance.

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).

Introduction: Addressing physical inactivity is a promising dementia risk reduction strategy due to its direct benefits for brain health, and indirect benefits for other modifiable dementia risk factors. A potential limitation of previous interventions is that they often overlook how increasing physical activity affects other behaviours throughout the 24-hour day, such as sleep and sedentary behaviour, which are also important for brain health. Further, interventions are rarely tailored to the individual, considering their needs, preferences and constraints that may serve as barriers or facilitators to behaviour change. The current phase I randomised controlled trial, Small Steps , aims to investigate feasibility, acceptability and preliminary effectiveness of a personalised 24-hr time-use intervention to improve lifestyle and cognitive health in older adults. Methods and analysis: Participants aged ≥65 years from Adelaide, South Australia will be recruited and randomised to either the Extended or Condensed program. During the first 12 weeks, participants in the Extended program will use a tailored website to set personalised weekly goals to move towards their ‘optimal’ 24-hr day for brain health, facilitated by weekly website ‘check-ins’ and weekly phone calls with a research staff member. Participants randomised to the Condensed program will have access to the website educational resources only but will not undergo personalised goal setting or telephone calls. Following the introductory phase (first 12 weeks), phone calls will be gradually withdrawn for the Extended program. Primary (feasibility and acceptability) and secondary outcomes (changes in time use, cognitive function and behaviour change metrics) will be assessed 12, 24 and 36 weeks after the beginning of the intervention. Conclusions: Given the major and growing financial and social burdens associated with dementia, if successful, this trial will be the first to facilitate effective knowledge translation and personalisation of 24-hr time-use intervention approaches for dementia risk-reduction. Ethics and dissemination: Ethics approval has been obtained from the University of South Australia’s Human Research Ethics Committee (205989). Study findings will be disseminated through peer-reviewed journal articles, conference presentations, media releases and community engagement. Trial registration number: The clinical trial protocol was registered at ClinicalTrials.gov (unique protocol ID: NCT06291909 ). STRENGTHS AND LIMITATIONS OF THIS STUDY: The Small Steps study will investigate the feasibility, acceptability and preliminary effectiveness of a personalised 24-hour time-use intervention to improve lifestyle and cognitive health in 88 community-dwelling older adults. Participants randomised to the Extended program (intervention) will be supported to improve their physical activity, sleep and sedentary behaviour patterns for 12 weeks with weekly researcher phone calls and website check-ins. Intervention goals will be personalised to the individual based on their current time use, projected ‘optimal’ time use, and their preferences and constraints associated with 24-hr time use. The intervention was co-designed with a separate cohort of community-dwelling older adults and allied health professionals. Recruitment will be based on self-report physical activity levels, which may result in recruitment of participants who have underestimated their activity levels and limit the generalisability of the findings.

Purpose: This study aimed to explore dietary profiles of a night shift working population with overweight/obesity and the impact of different shift work schedules (rotating vs. fixed night) on their diet. Methods: Participants from a randomised controlled trial (SWIFt trial) provided 7-day food diaries at study enrolment. Mean energy intakes (EI), and mean percentage of EI as nutrients (macronutrients, saturated fat, added sugar, alcohol) grams of fibre and milligrams of sodium, were assessed against recommendations for Australian adults. Energy intake was assessed for underreporting. Regression analyses were performed on nutrient intakes whilst controlling for individual and lifestyle factors (age, gender, BMI, physical activity, shift work exposure, occupation and shift schedule). Results: The diet of night shift workers ( N = 245, aged 46.8 ± 9.8 (mean ± SD) years and 53% female) was characterised as high in fat, saturated fat and sodium, while low in carbohydrate and fibre compared with recommendations, regardless of shift work schedule. However, the mean 24 h EI of rotating shift workers was higher than fixed night workers (9329 ± 2915 kJ/day vs. 8025 ± 2383 kJ/day, p < 0.001), even after assessing plausible EI reporters only ( n = 130) (10968 ± 2411 kJ/day vs. 9307 ± 2070 kJ/day, p < 0.001). Furthermore, those performing rotating schedules presented with higher sodium and alcohol consumption. Conclusion: These findings support the evidence of shift work being associated with poorer dietary profiles, which likely contribute towards worsened metabolic health amongst night shift workers. Dietary strategies that target problematic eating habits and address unique challenges of working shift schedules are needed to mitigate metabolic health risk in shift working populations.