Effects of Dinner Timing on Sleep Stage Distribution and EEG Power Spectrum in Healthy Volunteers

Association of Evening Eating with Sleep Quality and Insomnia among Adults in a Brazilian National Survey

Objective  To examine the association of evening eating clock time, its elapsed time to the midpoint of sleep (TEM), consumption of caffeine and sugary foods, and reporting dinner as the largest meal with sleep quality indicators and insomnia. Methods  Participants ( n  = 2,050;18-65y) were part of population-based research, with virtual data collection. Logistic regression models were fitted to assess differences in the ORs(95%CI) of sleep duration < 7 hours, sleep latency > 30 minutes, poor sleep quality, and insomnia (outcomes) with the evening diet-related variables. Linear regression analyses evaluated differences in sleep duration and latency associated with the same variables. Restricted cubic splines were used to study the shape of the association of eating event clock time and TEM with sleep duration and latency. Results  Each additional hour of evening eating clock time and of the TEM, respectively increased and decreased, the odds of sleep duration < 7/h [OR(95%CI):1.30(1.20,1.40); OR(95%CI):0.51(0.47,0.56)], sleep latency > 30min [OR(95%CI):1.14(1.07,1.22); 0.88(0.83,0.94)], poor sleep quality [OR(95%CI):1.21(1.13,1.30); 0.80(0.76,0.85)] and insomnia [OR(95%CI):1.12(1.04,1.20); 0.89(0.84,0.95)]. We found a dose-response association between evening eating (clock time and TEM) and sleep duration. The shortest latency was seen when evening eating was ∼20:00 and ∼7-8 hours before the midpoint of sleep. Participants who reported dinner as the largest meal and consumed caffeine and sugary foods/beverages after 18:00 presented higher odds of sleep duration < 7 hours, poor quality, and insomnia. Conclusions  Our findings indicate that an early-eating schedule has beneficial sleep effects and that it will be necessary to consider evening eating patterns and timing, along with the existing sleep and circadian hygiene, to improve sleep quality and circadian health.

Diet and sleep quality in chilean university students

OBJECTIVES

To evaluate an association between eating patterns and sleep quality in Chilean university students.

METHODS

A cross-sectional analytical study was conducted. Participants included students from 4 Chilean universities. Each student was administered survey Questionnaire on the frequency of healthy and unhealthy eating habits and Pittsburgh Sleep Quality Index and their weight and height were taken to obtain the Body Mass Index (BMI).

RESULTS

A total of 1,079 young university students, 80.26 % were women and the average age was 21.7 years. The 73.68 % have inadequate sleep quality. There is a significant differences in frequency between sleep quality and the intake of breakfast (p<0.001), fish (p<0.05) and dinner (p<0.05), that is, university students who reported optimal sleep consume breakfast and dinner on a daily basis and their fish intake is in line with nutritional recommendations. With respect to the association between sleep quality and healthy dietary patterns, it is observed a significant association (p<0.01) between optimal sleep and daily breakfast consumption in model 3 (Odds Ratio (OR): 0.61 (0.46-0.82)). Regarding unhealthy dietary patterns, a significant association (p<0.05) is observed in model 3 between sleep quality and alcohol consumption (OR: 1.42 (1.02-1.96)). Furthermore, a significant association between optimal sleep and salt consumption is observed in both model 2 (OR: 0.73 (0.54-0.99)) and model 3 (OR: 0.72 (0.53-0.97)). Finally, a significant relationship between not tobacco use and optimal sleep is observed (OR: 0.68 (0.48-0.96)).

CONCLUSION

A positive relationship between healthy diet and sleep quality was observed in university students, which certain dietary patterns, such as the consumption of breakfast and low salt consumption and alcohol, are crucial to talk about a good sleep quality in this population group.

Sex-specific chrono-nutritional patterns and association with body weight in a general population in Spain (GCAT study)

BACKGROUND

Altered meal timing patterns can disrupt the circadian system and affect metabolism. Our aim was to describe sex-specific chrono-nutritional patterns, assess their association with body mass index (BMI) and investigate the role of sleep in this relationship.

METHODS

We used the 2018 questionnaire data from the population-based Genomes for Life (GCAT) (n = 7074) cohort of adults aged 40-65 in Catalonia, Spain, for cross-sectional analysis and its follow-up questionnaire data in 2023 (n = 3128) for longitudinal analysis. We conducted multivariate linear regressions to explore the association between mutually adjusted meal-timing variables (time of first meal, number of eating occasions, nighttime fasting duration) and BMI, accounting for sleep duration and quality, and additional relevant confounders including adherence to a Mediterranean diet. Finally, cluster analysis was performed to identify chrono-nutritional patterns, separately for men and women, and sociodemographic and lifestyle characteristics were compared across clusters and analyzed for associations with BMI.

RESULTS

In the cross-sectional analysis, a later time of first meal (β 1 h increase = 0.32, 95% CI 0.18, 0.47) and more eating occasions (only in women, β 1 more eating occasion = 0.25, 95% CI 0.00, 0.51) were associated with a higher BMI, while longer nighttime fasting duration with a lower BMI (β 1 h increase=-0.27, 95% CI -0.41, -0.13). These associations were particularly evident in premenopausal women. Longitudinal analyses corroborated the associations with time of first meal and nighttime fasting duration, particularly in men. Finally, we obtained 3 sex-specific clusters, that mostly differed in number of eating occasions and time of first meal. Clusters defined by a late first meal displayed lower education and higher unemployment in men, as well as higher BMI for both sexes. A clear "breakfast skipping" pattern was identified only in the smallest cluster in men.

CONCLUSIONS

In a population-based cohort of adults in Catalonia, we found that a later time of first meal was associated with higher BMI, while longer nighttime fasting duration associated with a lower BMI, both in cross-sectional and longitudinal analyses.

Prefrontal, Frontal, and Temporal Theta EEG Asymmetries and Self-Reports of Emotional Regulation

Previous studies have shown that right-sided frontal alpha asymmetry (fAA) is an electroencephalography (EEG) marker for negatively valenced emotions and a marker for negative self-perceptions of a person's psychosocial interactions. Alpha activity is affected by the changes in visual stimulation associated with eye-opening and eye-closing; theta activity is not so affected. Therefore, this analysis investigates the relationship between an individual's theta asymmetry and self-perceptions of their psychosocial interactions. We used quantitative electroencephalographic (qEEG) data from eight right-handed male medical students aged between 19 and 38 years, recorded under eyes-open (EO) and eyes-closed (EC) conditions. Significant correlations were found between self-reported measures of psychosocial interactions via the Interactive Self-Report Inventory (ISI). The main finding was that greater left-sided frontal temporal asymmetry (fTA) under both EO and EC conditions was associated with lower "regulated" ISI scores and lower "dependent" ISI scores. Greater left-sided temporal theta asymmetry (tTA), under EC conditions, was associated with higher "anxious" ISI scores. Greater left-sided prefrontal theta symmetry (pfTA), under EO conditions, was associated with lower "relaxed" ISI scores. These findings suggest that theta asymmetries in the frontal, prefrontal, and temporal cortices may be indicative of negative emotional states. The results of this study underscore the potential of pfTA, fTA, and tTA to be used as biomarkers for cognitive-emotional balance. The implications for mental health interventions, particularly personalized therapeutic approaches, are significant.

The Effect of Prebedtime Behaviors on Sleep Duration and Quality in Children: Protocol for a Randomized Crossover Trial

BACKGROUND

It is recommended that children should avoid eating dinner, being physically active, or using screens in the hour before bed to ensure good sleep health. However, the evidence base behind these guidelines is weak and limited to cross-sectional studies using questionnaires.

OBJECTIVE

The aim of this randomized crossover trial was to use objective measures to experimentally determine whether recommendations to improve sleep by banning electronic media, physical activity, or food intake in the hour before bed, impact sleep quantity and quality in the youth.

METHODS

After a baseline week to assess usual behavior, 72 children (10-14.9 years old) will be randomized to four conditions, which are (1) avoid all 3 behaviors, (2) use screens for at least 30 minutes, (3) be physically active for at least 30 minutes, and (4) eat a large meal, during the hour before bed on days 5 to 7 of weeks 2 to 5. Families can choose which days of the week they undertake the intervention, but they must be the same days for each intervention week. Guidance on how to undertake each intervention will be provided. Interventions will only be undertaken during the school term to avoid known changes in sleep during school holidays. Intervention adherence and shuteye latency (time from getting into bed until attempting sleep) will be measured by wearable and stationary PatrolEyes video cameras (StuntCams). Sleep (total sleep time, sleep onset, and wake after sleep onset) will be measured using actigraphy (baseline, days 5 to 7 of each intervention week). Mixed effects regression models with a random effect for participants will be used to estimate mean differences (95% CI) for conditions 2 to 4 compared with condition 1.

RESULTS

Recruitment started in March 2024, and is anticipated to finish in April 2025. Following data analysis, we expect that results will be available later in 2026.

CONCLUSIONS

Using objective measures, we will be able to establish if causal relationships exist between prebedtime behaviors and sleep in children. Such information is critical to ensure appropriate and achievable sleep guidelines.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12624000206527; https://tinyurl.com/3kcjmfnj.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/63692.

Dietary and Lifestyle Strategies for Obesity

The prevalence of obesity globally has tripled over the last half century, and currently affects around 650 million adults and 340 million children and adolescents (ages 5-19 years). Obesity contributes towards >50 co-morbidities and premature mortality. Obesity is a highly stigmatised condition that is associated with much mental and emotional distress and dysfunction. Thus, obesity is a major contributor to healthcare expenditure globally. Traditionally, the management of obesity stratifies into three major groups that include metabolic (bariatric) surgery, pharmacotherapies, and lifestyle (primarily dietary) strategies. Although listed as a separate category, dietary strategies for obesity remain a central component of any management plan, and often complement other surgical and pharmacotherapeutic options. Indeed, the effectiveness of any management approach for obesity relies upon successful behavioural changes, particularly relating to eating behaviours. In this concise review, we explore the foundational pillars of dietary strategies for obesity: sleep, listening, routine, de-stressing and optimisation of social conditions. We then discuss the importance of balancing dietary macronutrients (including dietary fibre, carbohydrates, protein and ultra-processed foods [UPFs]) as a key dietary strategy for obesity. Although we focus on general principles, we should provide bespoke dietary strategies for our patients, tailored to their individual needs. Rather than judging the utility of a diet based simply on its associated magnitude of weight loss, we should adopt a more holistic perspective in which a dietary strategy is valued for its overall health benefits, including the nurturing of our gut microbiota, to enable them to nurture and protect us.

The Impact of Lunch Timing on Nap Quality

PURPOSE

Previous research has established that food intake is a biological regulator of the human sleep-wake cycle. As such, the timing of eating relative to sleep may influence the quality of sleep, including daytime naps. Here, we examine whether the timing of lunch (1 h vs. 2 h interval between lunch and a napping opportunity) impacts the quality of an afternoon nap.

METHODS

Using a randomized within-subject design over two separate experimental sessions (7 days apart), participants (n = 40, mean age = 25.8 years) consumed lunch 1 h and 2 h prior to an afternoon nap opportunity. Polysomnography and subjective self-reports were used to assess sleep architecture, sleepiness levels, and nap quality.

RESULTS

Results revealed no significant differences in subjective ratings of sleep quality and sleepiness, or in sleep architecture (total sleep time, sleep efficiency, sleep onset latency, sleep stages) between the 1 h and 2-h lunch conditions.

CONCLUSIONS

All sleep measures were similar when napping followed eating by either 1 h or 2 h, suggesting that eating closer to nap onset may not negatively impact sleep architecture and quality. Future research should continue to identify conditions that improve nap quality, given the well-documented benefits of naps to reduce sleep pressure and improve human performance.

Chrono-nutrition and sleep: lessons from the temporal feature of eating patterns in human studies - A systematic scoping review

An emerging field of research has revealed a bidirectional relationship between sleep and diet, highlighting the potential role of a healthy diet in improving sleep. However, the impact of chrono-nutrition on sleep remains less explored. Here we conducted a systematic scoping review, considering the multiple dimensions of chrono-nutrition, to describe the extent, range, and nature of the existing literature in this area (PROSPERO: CRD42021274637). There has been a significant increase in the literature exploring this topic over the past six years (almost 67 % of the evolving literature). A breakdown of the included studies was performed according to three major chrono-nutritional dimensions: meal timing [n = 35], irregular eating patterns [n = 84], and frequency of eating occasions [n = 3]. Meal timing included three sub-dimensions: breakfast skipping [n = 13], late eating [n = 16], and earlier vs later meals schedules [n = 6]. Irregular meal patterns included three sub-dimensions: diurnal fasting [n = 65], intermittent fasting [n = 16], and daily meal patterns [n = 3]. Frequency was the least studied dimension (n = 3). We provided a synthetic and illustrative framework underlining important preliminary evidence linking the temporal characteristics of eating patterns to various facets of sleep health. Nonetheless, much work remains to be done to provide chrono-nutrition guidelines to improve sleep health in the general population.

Association of sleep patterns and water intake with cognitive functions in adults in an urban environment

Objectives

To explore the behavior patterns of students and working adults regarding the duration and quality of sleep and water intake in an urban environment and to identify the relationship between nighttime sleep extent and water intake with mood and cognitive performance.

Methods

This was a descriptive correlational study conducted at Islamic International Medical College, Riphah University at the Pathology department from March to June 2022. A total of 160 participants with age range of 20 to 50 years completed a self-report questionnaire regarding sleep patterns, water intake, and perceptions of mood, concentration, and memory. Analyzed the relationship between sleep duration, water intake, mood, mindfulness/concentration, and memory using Kendall's Tau-b correlation coefficient in SPSS 22.

Results

A significant number (28.7%) of participants had a sleep duration of ≤ 6 hours, with 41.3% sleeping after midnight. 82.5% of the participants switch off-screen just before sleeping. 63.7% have a routine water intake of less than 2 L/day. An aberrant statistically significant negative correlation between total sleeping hours and mood (τb = -.313, p = 0.004) was identified, showing a negative effect on mood with a sleeping time of ≥ 9 hours when compared with the other two groups (6-9 hours, τb = - .689, p = 0.001, ≤ 6hours, τb = - .697, p = 0.001). A significant correlation between daily water intake and concentration was found, wherein a decrease in daily water intake showed a negative effect on concentration (τb = .289, p = 0.008).

Conclusions

Sleep duration and water intake patterns may affect mood and cognitive performance. Regular sufficient nighttime sleep and adequate hydration may help improve cognitive functioning and mood.

Sleep and circadian hygiene practices association with sleep quality among Brazilian adults

Objective

To investigate the association of sleep and circadian hygiene practices (sleep-promoting and sleep-disturbing behaviors) with sleep quality indicators.

Methods

Participants (n = 2050; 18-65 y) were part of virtual population-based research. Logistic regression models were fitted to assess differences in the OR (95% CI) of poor quality with sleep-promoting/disturbing practices (time-of-day of exercise, pre-bedtime routine, naps, electronic devices with illuminated screens, caffeine and alcohol consumption, and smoking). Linear regression analyses evaluated differences in sleep duration, latency, and awakenings associated with the same variables. Restricted cubic splines were used to study the shape of the association of screen time before bed with sleep duration, latency, and awakenings. Analyses were adjusted for age, sex, region, marital status, educational level, evening diet quality, and BMI.

Results

Evening use of electronic devices with illuminated screens showed a negative effect on all sleep parameters. Reporting dinner as the largest meal and evening caffeine consumption was associated with shorter sleep duration and longer sleep latency. Smokers had higher odds of longer latency. A protective effect of morning exercises was demonstrated on sleep quality, latency, and awakenings. Alcohol consumers presented lower odds of poor quality and lower frequency of awakenings. Pre-bedtime practices showed no or negative effect on sleep outcomes.

Conclusions

Recommendations to promote sleep quality and prevent sleep-related problems, with corresponding circadian health benefits, should include engaging in regular exercise, preferably in the morning, and avoiding naps, heavy meals close to bedtime, caffeine, smoking, and evening screen exposure.

Association between dinner timing and glucose metabolism in rural China: A large-scale cross-sectional study

OBJECTIVES

Meal timing is a major risk factor for metabolic disease. The aim of this study was to assess the relationship between dinner timing and glucose metabolism in the rural Chinese population.

METHODS

This cross-sectional study included 7701 participants from a Henan rural cohort study. Basic information was collected by in-person questionnaires. Multiple linear regression analysis was used to evaluate the relationship between dinner timing and fasting insulin (FINS), fasting plasma glucose (FPG), and homeostatic model assessment for insulin resistance (HOMA-IR). Restricted cubic spline was employed to investigate the dose-response relationship between dinner timing and FINS, FPG, and HOMA-IR. A generalized linear model was used to explore the interaction effect of age and dinner timing on FINS, FPG, and HOMA-IR.

RESULTS

After adjusting for confounding factors, FINS concentration was reduced by 0.482 mmol/L (P < 0.001) for each hour delay in dinner timing. Furthermore, the HOMA-IR index decreased by 0.122 mmol/L for each hour delay. The results indicated a noticeable trend of decreasing values associated with later dinner timing (FINS: Poverall association < 0.001, Pnonlinear association = 0.144; HOMA-IR: Poverall association = 0.001, Pnonlinear association = 0.186). The interaction between age and dinner time significantly correlated with FINS and HOMA-IR (P < 0.05). This relationship was statistically significant before 69 y (P < 0.05).

CONCLUSION

A significant association between dinner timing and glucose metabolism was observed in the rural Chinese population. Delayed dinner timing may be associated with lower fasting insulin. The negative effect of dinner timing on FINS and HOMA-IR was diminished with age.

A Delayed Evening Meal Enhances Sleep Quality in Young Rugby Players

The aim of this study was to examine the effect of delayed evening mealtime on sleep quality in young athletes. Twelve rugby players (age 15.8 ± 0.7 years) participated in a crossover within-participant design. Adolescents spent five consecutive days in each of two conditions, separated by a 2-week washout period: routine dinner (3.5 hr before bedtime) and late dinner (LD, 1.5 hr before bedtime). Other mealtimes as well as bedtime and wake-up time were usual and remained the same in both conditions. Their schedules, dietary intakes, and physical activity were controlled and kept constant throughout the study. Sleep was assessed using polysomnography on the first and the last nights in the individual rooms of the boarding school. An increase in total sleep time by 24 min (p = .001, d = 1.24) and sleep efficiency by 4.8% was obtained during LD (p = .001, d = 1.24). Improvement in sleep efficiency was mainly due to a lower wake after sleep onset (-25 min, p = .014, d = -3.20), a decrease of microarousals (-25%, p = .049, d = -0.64), and awakenings ≥90 s (-30%, p < .01, d = -0.97) in LD compared to routine dinner. There were no significant differences in sleep architecture except for a shorter slow-wave sleep (N3) latency (-6.9 min, p = .03, d = -0.778) obtained during LD. In this study, evening dinner 1.5 hr before bedtime leads to better quality and less fragmented sleep compared to evening dinner 3.5 hr before bedtime in young athletes.

Sleep, Physical Activity, and Diet of Adults during the Second Lockdown of the COVID-19 Pandemic in Greece

The aim of the present study was to evaluate the possible correlations between sleep, physical activity, and diet in the general population of Greece during the second lockdown due to COVID-19 pandemic. A web-based questionnaire including 28 items was completed by 494 adults (age 31.5 ± 12.4 years). Half of the participants (49.8%) reported good, 44.1% moderate, and 6.1% bad quality of sleep, whereas 17.2% answered that the quality of sleep improved, 56.5% did not change, and 26.3% worsened compared to a normal week. Compared to normal, sleep duration in lockdown increased by 0.24 h (95% CI; 0.13, 0.35; p < 0.001, d = 0.198). More under-weight (32.4%) and obese (34.1%) respondents reported worsened quality of sleep in lockdown compared with normal (25.6%) and overweight participants (22.7%) (p = 0.006, Cramer's φ = 0.191). A small effect for BMI group on sleep duration was observed (p = 0.011, η2 = 0.023), where overweight and obese slept less (-0.44 h and -0.66 h, respectively) than normal weight participants. Subjects with the highest percentage of increased food consumption reported decreased sleep duration (p = 0.012) and worsened sleep quality (p = 0.003). Compared with a normal week, physical activity of a high and moderate intensity decreased for 43.0% and 37.0% of participants, did not change in 32.9% and 36.1% of participants, and increased in 24.1% 26.9%, respectively, whereas walking time decreased in 31.3%, did not change in 27.3%, and increased in 41.5% of participants. Increased high and moderate intensity physical activity was related with an improvement in sleep quality (p < 0.001). Those with decreasing walking time reported the highest percentage of decreased sleep quality (p = 0.006) and worsened sleep quality (p = 0.016). In conclusion, both quality and quantity of sleep were impaired during the second lockdown and the observed changes were associated with diet and physical activity.