Role of chronotype in dietary intake, meal timing, and obesity: a systematic review

The Role of the Chronotype in Developing an Excessive Body Weight and Its Complications-A Narrative Review

The chronotype, the personal predisposition towards morning or evening activities, significantly influences health conditions, sleep, and eating regulations. Individuals with evening chronotypes are often at a higher risk for weight gain due to misalignment between their natural tendencies of functioning and social schedules, resulting in insufficient sleep, disruptions in eating habits, and decreased physical activity levels. Often, impaired glucose tolerance and changes in melatonin, adiponectin, and leptin secretion, along with alterations in the clock gene functions in subjects with evening preferences, may be predisposed to obesity. These disturbances contribute to metabolic dysregulation, which may lead to the subsequent onset of obesity complications, such as hypertension, type 2 diabetes, sleep apnea, and liver diseases. Targeting critical components of the circadian system and synchronizing people's chronotypes with lifestyle conditions could deliver potential strategies for preventing and treating metabolic disorders. Thus, it is recommended to take a personalized chronobiological approach to maintain a normal body weight and metabolic health. Nevertheless, future studies are needed to identify the clear mechanisms between the chronotype and human health. This article provides a narrative review and discussion of recent data to summarize studies on the circadian rhythm in the context of obesity. The manuscript represents a comprehensive overview conducted between August and November 2024 using the National Library of Medicine browser (Medline, Pub-Med, Web of Science).

Association of dietary insulin index (DII) and dietary insulin load (DIL) with circadian rhythm and quality of sleep among overweight and obese women: a cross-sectional study

BACKGROUND

Obesity is a global issue, with over 1.9 billion adults overweight. Disruption of circadian rhythms (CR) leads to obesity and metabolic disorders. Dietary nutrition significantly impacts sleep disorders and disruption in CR, influencing hormones and inflammation, which can contribute to insomnia. The dietary insulin index (DII) and dietary insulin load (DIL) are important factors in determining sleep quality. The current study aims to investigate the association between DII and DIL with CR and sleep quality among with overweight and obesity women.

METHODS

A case-control study involved 280 overweight/obese women aged 25-40 from Tehran University Medical Science. They were assessed for dietary intake, physical activity, and sleep using validated questionnaires. The study also assessed body composition, bioelectrical impedance analysis, biochemical components, anthropometric components, and blood pressure. Socio-demographic and lifestyle characteristics, such as age, educational level, physical activity, and smoking habits, were also assessed through questionnaires.

RESULT

In the crude and adjustment models, high adherence of DII compared with lower adherence increased the odds of poor sleep quality index among participants. This significant association remained even after adjustment for confounding variables (P < 0.05), such that the odds of poor sleep quality index was 1.92 times higher.

CONCLUSION

This study showed high adherence to DII and DIL may cause CR disruption. Furthermore, higher adherence to DII lead to poor sleep quality in women.

Chronotype, temporal patterns of eating and diet composition on work and work-free days

Temporal patterns of eating and diet composition are influenced by factors including circadian preference (chronotype) and work schedule, yet their combined influence is unknown. We investigated relationships between chronotype, temporal eating patterns (duration of eating window (DEW), time of first (FEO) and last (LEO) eating occasions), and diet composition on workdays (WD) and work-free days (FD). Non-shift workers (n = 39) completed the Chrononutrition Questionnaire (CNQ) (age: 38.8 ± 17.2 years, BMI: 24.8 ± 4.78 kg/m2, 82% female) that captures chronotype and temporal eating patterns, and returned work diaries (work schedule) and 7-day food diaries (diet composition) after 2 weeks. Twenty-nine participants provided dietary data for at least two work and work-free days. Later chronotype was associated with later FEO on FD (rs = 0.45, p = 0.004), later LEO on FD (rs = 0.60, p < 0.001) and WD (rs = 0.61, p < 0.001), and longer DEW on WD (rs = 0.37, p = 0.024). Relationships between chronotype and diet composition were small. Later FEO was associated with higher % energy from fat (rs = 0.39, p = 0.043) and lower fibre intake (rs = -0.69, p < 0.001) on WD. Later chronotypes had shorter and later eating windows on FD than WD. Our findings suggest that relationships between chronotype, temporal eating patterns, and diet composition differ by day type. Further investigation may inform dietary strategies that are day-specific.

Exploring factors influencing late evening eating and barriers and enablers to changing to earlier eating patterns in adults with overweight and obesity

Late evening eating is a potential risk factor for overconsumption and weight gain. However, there is limited qualitative research investigating the complex factors that influence late evening eating in adults living with obesity. Identifying the factors that influence late evening eating can inform interventions to reduce late evening eating and associated health risks. Therefore, this study aimed to: i) explore factors that contribute to eating late, and ii) apply the Capability, Opportunity, and Motivation Behaviour (COM-B) model to understand the barriers and enablers to changing to earlier food intake timings in UK adults who report eating late. Semi-structured interviews with seventeen participants [32.47 ± 6.65 years; 34.68 ± 7.10 kg/m2; 71% female (n = 12); 41% White (n = 7)] investigated reasons for late evening eating and the potential barriers and enablers to changing to earlier eating patterns. Thematic analysis identified four main contributors to late evening eating: 1) internal signals (e.g., feeling hungry in the evening); 2) external and situational factors (e.g., work schedules and the food-rich environment); 3) social factors (e.g., interactions with family) and 4) behavioural and emotional factors (e.g., personal preferences and negative feelings in the evening). Time constraints and work schedules were identified as main barriers to changing to earlier eating patterns. Whereas, having high motivation (e.g., contentment with eating earlier in the evening) and interpersonal support were identified as main enablers to eating earlier. This study provides in-depth insights into the psychological, social, and environmental factors contributing to late evening eating. The findings highlight potential targets for future interventions to facilitate earlier eating times in individuals at risk of overweight and obesity.

Chrononutrition and metabolic health in children and adolescents: a systematic review and meta-analysis

CONTEXT

Obesity has emerged as a global health issue for the pediatric population, increasing the need to investigate physiopathological aspects to prevent the appearance of its cardiometabolic complications. Chrononutrition is a field of research in nutritional sciences that investigates the health impact of 3 different dimensions of feeding behavior: regularity of meals, frequency, and timing of food intake.

OBJECTIVE

We carried out a systematic review and meta-analysis to investigate the association between chrononutrition in children and adolescents and the risk of overweight/obesity or a cluster of metabolic abnormalities related to glucose and lipid metabolism, blood pressure, and cardiovascular disease risk.

DATA EXTRACTION

A literature search was performed using PubMed, EMBASE, and The Cochrane Library for relevant articles published before August 2022.

DATA ANALYSIS

A total of 64 articles were included in the narrative synthesis (47 cross-sectional and 17 cohort studies), while 16 studies were included in the meta-analysis. Meta-analysis showed that non-daily breakfast consumers (≤6 d/wk) had a higher risk of overweight/obesity (odds ratio [OR], 1.45; 95% confidence interval [CI], 1.08-1.82] compared with daily breakfast eaters (7 d/wk). Similarly, irregular breakfast consumption (only 0-to-3 times/wk) increased the risk of abdominal obesity (waist-to-height ratio ≥ 0.5) compared with regular consumption (5-to-7 times/wk) (OR, 1.38; 95% CI, 1.26-1.49). There was evidence to suggest that a regular frequency of meal consumption (≥4 times/d) is preventive against overweight/obesity development compared with fewer meals (≤3 times/d) (OR, 0.83; 95% CI, 0.70-0.97). In the narrative synthesis, snacking habits showed controversial results, while food timing was the most understudied dimension.

CONCLUSION

Overall, our data indicate a potential implication of chrononutrition in affecting pediatric metabolic health; however, the evidence of this association is limited and heterogeneous. Further prospective and intervention studies with a consistent approach to categorize the exposure are needed to elucidate the importance of chrononutrition for pediatric metabolic health.

Eating frequency, timing of meals, and sleep duration before and after a randomized controlled weight loss trial for breast cancer survivors

PURPOSE

To examine eating frequency, timing of meals, and sleep duration before and after a weight loss intervention for breast cancer survivors.

METHODS

Female breast cancer survivors (n = 159; 55 ± 9 years; 31.4 ± 5.0 kg/m2; stage I-III, median [IQR] 9.5 [5.5] months post-diagnosis) participated in a randomized controlled trial of a 12-month weight loss intervention versus usual care. Eating frequency, proportion of daily calories consumed after 5 PM, eating after 8 PM, nightly fasting duration, and sleep duration were estimated and categorized based on existing associations with factors influencing breast cancer prognosis and breast cancer outcomes. These behaviors at baseline were compared to women from an Australian national survey with similar age and BMI range. Mixed-effects linear regression models were used to examine the changes in health behaviors from baseline to 18 months between intervention and usual care groups.

RESULTS

Before the trial, eating after 8 PM (67%) was higher, and short nightly fasting duration (< 13 h, 83%) and long sleep duration (> 9 h/day, 26%) were marginally higher, in breast cancer survivors than women in the national survey (52%, 75%, and 17%, respectively). "Less optimal" eating behaviors and sleep duration tended to co-occur. Behaviors remained unchanged over the 18-month follow-up, irrespective of the study group (p > 0.05; Cohen's effect sizes < 0.3).

CONCLUSIONS

Later timing of eating and long sleep duration were prevalent in breast cancer survivors and continued following a weight loss intervention.

IMPLICATIONS FOR CANCER SURVIVORS

Future multi-behavior interventions in breast cancer survivors should consider specific messages to target eating timing behaviors and sleep.

The association between diet and sleep with internalising symptoms in young athletes: a serial multiple mediation models

Introduction

Athletes frequently experience anxiety and depression at rates similar to or higher than non-athletes. A balanced diet can alleviate athletes internalizing symptoms. Moreover, diet and sleep are all associated with internalising symptoms. Our study investigates how sleep quality mediates the impact of dietary habits on internalizing symptoms in athletes.

Methods

The current cross-sectional study involved 758 Chinese young athletes. The adapted Australian Athletes Diet Index was used to assess dietary patterns, and sleep was measured using the Athletes Sleep Screening Questionnaire. The Generalised Anxiety Disorder 7 scale and the Patient Health Questionnaire 9-item scale were used to assess symptoms of anxiety and depression. Structural Equation Modelling (SEM) analysis was used to examine the mediating role of sleep quality in young athletes. Raw scores of chronotypes, sleep quality, anxiety and depression were calculated for the statistical analysis.

Results

No significant indirect effects were found in adolescents. In adult athletes, diet mediated the relationship between chronotype and sleep quality (β = -0.028, p  <  0.001). Sleep quality mediated the association between diet and anxiety (β = -0.060, p = 0.001), and depression (β = -0.076, p = 0.001). Additionally, diet and sleep quality mediated the association between chronotypes and anxiety (β = -0.028, p = 0.001), and depression (β = -0.028, p = 0.001).

Conclusion

Sleep quality mediated the relationship between dietary patterns and internalising symptoms in young adult athletes. Additionally, diet and sleep quality mediated the association between chronotypes and internalising symptoms in young adult athletes.

Exploring the associations between chronotype, meal frequency, and physical activity: A population-based study in adults

Chronotype is an established concept designed to capture the internal clock's phase in real-life conditions. It is vital in many aspects of daily life and can interfere considerably with numerous factors in a given population. Recognizing nonmodifiable and modifiable factors is crucial for identifying covariates of interest when studying the link between chronotype and health status. To date, chronotype and its related factors have not been extensively investigated. The present study aimed to explore the association of chronotypes with meal frequency, physical activity, and demographic factors among the Saudi population. This cross-sectional web-based questionnaire involved 1369 adults (aged 18 years and above) from the general public in Saudi Arabia and was conducted between March and May 2019. Chronotype was assessed using the reduced version of the original Horne and Ostberg morningness-eveningness questionnaire (MEQ). Meal frequencies and demographics data (age, gender, marital status, place of residence, educational level, employment status, income) were obtained. Physical activity level was also obtained using the international physical activity questionnaire. The MEQ scores group individuals into three categories: morning-type, neither-type, and evening-type. The neither-type individuals represented 41.6% (95% confidence interval [CI], 37.5% - 45.6%) of the study population, followed by the morning-type (34.1%; 95% [CI], 29.8% - 38.4%), then the evening-type (24.3%, 95% [CI], 19.6% - 28.9%). Chronotype was significantly associated with age, marital status, employment status and monthly income (All p < 0.05). Significant associations between chronotype with meal frequencies (number of meals per day, breakfast frequency, lunch frequency, and dinner frequency) and physical activity were also observed (All p < 0.05). This study highlights that meal frequencies and physical activity levels are associated with chronotype distribution. Furthermore, demographics, including age, marital status, employment status, and income, were associated with chronotype distribution.

Temporal patterns of food consumption and their association with cardiovascular risk in rotating shift workers

OBJECTIVE

We aimed to evaluate the association of temporal patterns of food consumption with cardiovascular disease (CVD) risk.

METHODS

This cross-sectional study included male rotating shift workers in an iron ore extraction company. Data on food consumption was collected using a 24 h recall, applied by trained interviewers. The variables for temporal patterns of food consumption were: eating window, eating at night, number of meals and omission of breakfast. CVD-risk was measured by calculating the Framingham coronary heart disease risk score (FCRS), and classified as low risk or intermediate to high risk. Descriptive, univariate and multivariate logistic regression analyses examined the association between variables related to temporal patterns of food consumption and CVD-risk.

RESULTS

The study assessed 208 workers, the majority with 20-34 years (45.1%), non-white (77.2%), and 5 years or more in shift work (76.0%). Most participants had a feeding window exceeding 12 h (63.9%), consumed meals until 10 p.m. (68.1%), had five or more meals per day (54.8%), and did not skip breakfast (86.5%). Regarding CVD-risk, 43.8% of the participants were classified with intermediate to high risk for CVD. In the multivariate model, a feeding window (OR: 2.32; 95%CI: 1.01-5.35), eating after 10 p.m. (OR: 3.31; 95%CI: 1.01-11.0), and skipping breakfast (OR: 2.58; 95%CI: 1.07-6.19) increased the likelihood of intermediate to high CVD-risk. Conversely, having five or more meals per day decreased the odds (OR: 0.27; 95%CI: 0.08-0.92).

CONCLUSION

Eating window longer than 12 h, eating after 10 p.m., less than four meals a day and omission of breakfast, are associated with cardiovascular risk in shift workers.

The effect of circadian timing program for evening-chronotype individuals with obesity on obesity management and sleep quality: A randomized controlled trial

OBJECTIVES

The study aimed to investigate the effect of the circadian timing program (SİZAP) developed for evening-chronotype individuals with obesity on obesity management and sleep quality.

METHODS

This single-site, randomized controlled trial with an experimental research design was registered in ClinicalTrials.gov. It was reported in accordance with the "Consolidated Standards of Reporting Trials" (CONSORT) randomized controlled trial guidelines. The study sample consisted of 38 evening-chronotype individuals with first-degree obesity, with 19 individuals in each study group. The intervention group's sleep hygiene training was conducted and their lifestyle changes were ensured through SİZAP. The control group followed their normal daily lifestyle. No intervention was made in terms of the dietary practices of both groups. Study data were collected using the personal information form, the anthropometric measurement form, the Horne and Ostberg Morning and Evening Questionnaire (MEQ), the Impact of weight on quality of life-lite (IWQOL-lite), the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS), the sleep diary, and the data tracked via the website and smart bracelets.

RESULTS

It was determined that the participants in the SİZAP group had a statistically significant decrease in the anthropometric measurements and daytime sleepiness (p < 0.05). The sleep quality scores and the scores of the bodily functions sub-dimension of the quality of life scale were significantly better in the intervention group than in the control group (p < 0.05).

CONCLUSION

It was found that SİZAP is effective in obesity management in evening-chronotype individuals and increases weight loss success and sleep quality.

The association between diet quality and chrononutritional patterns in young adults

PURPOSE

Young adults eat erratically and later in the day which may impact weight and cardiometabolic health. This cross-sectional study examined relationships between chrononutritional patterns and diet quality in two young adult populations: a university and community sample.

METHODS

Three days of dietary data were collected including food images captured using wearable cameras. Chrononutritional variables were extracted: time of first and last eating occasions, caloric midpoint (time at which 50% of daily energy was consumed), number of eating occasions per day, eating window, day-to-day variability of the above metrics, and evening eating (≥20:00h). The Healthy Eating Index for Australian Adults scored diet quality. Statistical analyses controlled for gender, body mass index, and socio-economic status.

RESULTS

No significant associations between chrononutritional patterns and diet quality were found for all participants (n = 95). However, differences in diet quality were found between university (n = 54) and community (n = 41) samples with average diet quality scores of 59.1 (SD 9.7) and 47.3 (SD 14.4), respectively. Of those who extended eating ≥20:00 h, university participants had better diet quality (62.9±SE 2.5 vs. 44.3±SE 2.3, p < 0.001) and discretionary scores (7.9±SE 0.9 vs. 1.6±SE 0.6, p < 0.001) than community participants. University participants consumed predominately healthful dinners and fruit ≥20:00h whereas community participants consumed predominately discretionary foods.

CONCLUSION

For the general young adult population, meal timing needs to be considered. Food choices made by this cohort may be poorer during evenings when the desire for energy-dense nutrient-poor foods is stronger. However, meal timing may be less relevant for young adults who already engage in healthy dietary patterns.

Chronotype in relation to free and total testosterone in men

In the current study, we examined the association between eveningness and testosterone levels in men. Specifically, we differentiated between free and total testosterone fractions, with free testosterone being recognized as the most bioavailable form of this hormone. We collected blood samples from 298 men aged 18-44 to assess total and free testosterone. Additionally, we measured sleep timing variables using the Munich Chronotype Questionnaire. The main result of the current study indicated that evening chronotype was associated with higher levels of free testosterone, but was unrelated to total testosterone. Sleep loss was unrelated to the both testosterone fractions. We expanded prior findings by utilizing a more comprehensive testosterone assay what indicated that evening chronotype is primarily associated with the most bioavailable form of testosterone (i.e. free testosterone) in adult men.

Effect of timed dosing of usual antihypertensives according to patient chronotype on cardiovascular outcomes: the Chronotype sub-study cohort of the Treatment in Morning versus Evening (TIME) study

Background

Timing drug administration to endogenous circadian rhythms may enhance treatment efficacy. In the Chronotype sub-study of the Treatment in Morning versus Evening (TIME) clinical trial we examined whether timing of usual antihypertensive medications according to patient chronotype (a behavioural marker of personal circadian rhythm) may influence clinical cardiovascular outcomes.

Methods

This was a cohort sub-study of TIME, a prospective, randomised, open-label, blinded-endpoint, UK clinical trial of morning versus evening dosing of usual antihypertensive medications and cardiovascular outcomes. On August 3rd, 2020, all active TIME participants were invited to complete a validated chronotype questionnaire. Chronotype was quantitatively assessed as the mid sleep time on free days corrected for sleep debt on workdays (MSFsc). We analysed associations between chronotype and antihypertensive dosing time and explored their combined effect on cardiovascular outcomes (a composite endpoint of hospitalisation for non-fatal myocardial infarction (MI) or non-fatal stroke, and single components) using proportional hazard time-to-event models adjusted for baseline covariates. These were used to specifically test for interactions between dosing time and chronotype.

Findings

Between August 3, 2020, and March 31, 2021, 5358 TIME participants completed the online questionnaire. 2778 were previously randomised to morning dosing and 2580 to evening dosing of their usual antihypertensives. Chronotype was symmetrically distributed around a median MSFsc of 3:07 am. The composite endpoint increased for later MSFsc (later chronotype) dosed in the morning but not in those dosed in the evening (hazard ratios 1.46 [95% CI 1.14-1.86] and 0.96 [95% CI 0.70-1.30] per hour of MSFsc, respectively; interaction p = 0.036). Later chronotype was associated with increased risk of hospitalisation for non-fatal MI in the morning dosing group, and reduced risk in the evening dosing group (hazard ratios 1.62 [95% CI 1.18-2.22] and 0.66 [95% CI 0.44-1.00] per hour of MSFsc, respectively; interaction p < 0.001). No interaction between chronotype and antihypertensive dosing time was observed for stroke events.

Interpretation

Alignment of dosing time of usual antihypertensives with personal chronotype could lower the incidence of non-fatal MI compared to a 'misaligned' dosing time regimen. Future studies are warranted to establish whether synchronizing administration time of antihypertensive therapy with individual chronotype reduces risk of MI.

Funding

The TIME study was funded by the British Heart Foundation (CS/14/1/30659) with support from the British and Irish Hypertension Society.

Consumption of fruits and vegetables and its association with sleep duration among Finnish adult population: a nationwide cross-sectional study

Introduction

Sleep and diet are crucial determinants of overall health and wellbeing, with the potential to mutually influence each other. This study examined the association between sleep duration and fruits and vegetables (FV) consumption among Finnish adults.

Methods

The study analyzed data from the National FinHealth 2017 Study involving 5,043 adults aged 18 years and above. Participants reported their habitual sleep duration, and dietary consumption through a validated self-administered questionnaire. Confounders such as demographic, socio-economic factors, and chronotype were considered. A sensitivity analysis, which excluded energy under-reporters, was conducted to validate the findings.

Results

Mean dietary consumption was compared across three sleep duration categories (short, normal, long), revealing that short sleepers consumed 37 g/d fewer FV, and long sleepers consumed 73 g/d fewer FV than normal sleepers. Binary logistic regression analyses consistently demonstrated significant negative association between FV consumption and both short and long sleep duration across all models, even when adjusted for a range of covariates. Linear regression analyses revealed a positive but non-significant association between sleep duration and FV consumption that became significant when excluding energy under-reporters, particularly in model 1.

Discussion

This study suggests a consistent pattern where deviation from normal sleep duration was associated with decreased FV consumption, suggesting the need for considering sleep patterns in dietary intervention. The substantial role of accurate energy reporting in explaining these associations is highlighted. Further research, including longitudinal studies, is needed to better understand the mechanisms underlying these associations.

Biological clock regulation by the PER gene family: a new perspective on tumor development

The Period (PER) gene family is one of the core components of the circadian clock, with substantial correlations between the PER genes and cancers identified in extensive researches. Abnormal mutations in PER genes can influence cell function, metabolic activity, immunity, and therapy responses, thereby promoting the initiation and development of cancers. This ultimately results in unequal cancers progression and prognosis in patients. This leads to variable cancer progression and prognosis among patients. In-depth studies on the interactions between the PER genes and cancers can reveal novel strategies for cancer detection and treatment. In this review, we aim to provide a comprehensive overview of the latest research on the role of the PER gene family in cancer.

Digital Dietary Behaviors in Individuals With Depression: Real-World Behavioral Observation

BACKGROUND

Depression is often accompanied by changes in behavior, including dietary behaviors. The relationship between dietary behaviors and depression has been widely studied, yet previous research has relied on self-reported data which is subject to recall bias. Electronic device-based behavioral monitoring offers the potential for objective, real-time data collection of a large amount of continuous, long-term behavior data in naturalistic settings.

OBJECTIVE

The study aims to characterize digital dietary behaviors in depression, and to determine whether these behaviors could be used to detect depression.

METHODS

A total of 3310 students (2222 healthy controls [HCs], 916 with mild depression, and 172 with moderate-severe depression) were recruited for the study of their dietary behaviors via electronic records over a 1-month period, and depression severity was assessed in the middle of the month. The differences in dietary behaviors across the HCs, mild depression, and moderate-severe depression were determined by ANCOVA (analyses of covariance) with age, gender, BMI, and educational level as covariates. Multivariate logistic regression analyses were used to examine the association between dietary behaviors and depression severity. Support vector machine analysis was used to determine whether changes in dietary behaviors could detect mild and moderate-severe depression.

RESULTS

The study found that individuals with moderate-severe depression had more irregular eating patterns, more fluctuated feeding times, spent more money on dinner, less diverse food choices, as well as eating breakfast less frequently, and preferred to eat only lunch and dinner, compared with HCs. Moderate-severe depression was found to be negatively associated with the daily 3 regular meals pattern (breakfast-lunch-dinner pattern; OR 0.467, 95% CI 0.239-0.912), and mild depression was positively associated with daily lunch and dinner pattern (OR 1.460, 95% CI 1.016-2.100). These changes in digital dietary behaviors were able to detect mild and moderate-severe depression (accuracy=0.53, precision=0.60), with better accuracy for detecting moderate-severe depression (accuracy=0.67, precision=0.64).

CONCLUSIONS

This is the first study to develop a profile of changes in digital dietary behaviors in individuals with depression using real-world behavioral monitoring. The results suggest that digital markers may be a promising approach for detecting depression.

A tendency toward evening chronotype associates with less healthy diet among preschoolers: cross-sectional findings from the DAGIS study

Study Objectives

Evidence suggests that adolescents and adults with a later chronotype have poorer sleep habits and are more susceptible to unhealthy behaviors, but little is known about these associations in younger children. The objective of the study was to (1) identify and compare individual chronotype tendencies among preschool-aged children and (2) investigate associations of sleep dimensions and chronotype with diet.

Methods

Participants were 636 3-6 years old (mean ± SD age: 4.74 ± 0.89 years, 49% girls) preschoolers from the cross-sectional Increased Health and Well-Being in Preschoolers (DAGIS) study in Finland. Sleep duration, sleep variability (in duration and midpoint), social jetlag, and midsleep on weekends adjusted for sleep debt (MSWEadj) were measured with 7-day actigraphy. Morning, intermediate, and evening chronotype tendencies were defined based on the lowest and highest 10th percentile cutoffs of MSWEadj. Food, energy, and macronutrient intake were assessed from 3-day records. Associations between sleep dimensions and diet were assessed with regression models.

Results

MSWEadj was 1:13 ± 14 minutes for morning (n = 64), 2:25 ± 28 minutes for intermediate (n = 560), and 3:38 ± 15 minutes for evening (n = 64) chronotype tendency. Children with an evening chronotype tendency had greater social jetlag and sleep variability. Having an evening chronotype tendency was associated with higher added sugar, higher sugary food consumption, and lower vegetable consumption compared to intermediate tendency types. A later chronotype (MSWEadj) was associated with higher sugary food consumption, as well as lower vegetable and fiber intake. Sleep duration, social jetlag, and sleep variability were not associated with diet.

Conclusions

Several less healthy sleep and diet behaviors were observed among children with later chronotypes. Future public health interventions aimed towards children would benefit from taking into account chronotype.

Eating time variation from weekdays to weekends and its association with dietary intake and BMI in different chronotypes: findings from National Health and Nutrition Examination Survey (NHANES) 2017-2018

Evidence suggests that differences in meal timing between weekends and weekdays can disrupt the body's circadian rhythm, leading to a higher BMI. We aimed to investigate the associations between mealtime variation from weekdays to weekends (eating midpoint jetlag), dietary intake and anthropometric parameters, based on individuals' chronotype. The study utilised data from National Health and Nutrition Examination Survey 2017-2018. Food consumption was estimated by weighted average of participants' food intake on weekdays and weekends. Eating midpoint jetlag, defined as the difference between the midpoint of the first and last mealtimes on weekends and weekdays, was calculated. Chronotype was assessed by participants' mid-sleep time on weekends, adjusted for sleep debt. Linear regression analysis was conducted to investigate the associations between variables. The sample was categorised into chronotype tertiles. Among individuals in the third chronotype tertile, there was a positive association between eating midpoint jetlag and BMI (β = 1·2; 95 % CI (1·13, 1·27)). Individuals in the first tertile showed a positive association between eating midpoint jetlag and energy (β = 96·9; 95 % CI (92·9, 101·7)), carbohydrate (β = 11·96; 95 % CI (11·2, 12·6)), fat (β = 3·69; 95 % CI (3·4, 3·8)), cholesterol (β = 32·75; 95 % CI (30·9, 34·6)) and sugar (β = 8·84; 95 % CI (8·3, 9·3)) intake on weekends. Among individuals with an evening tendency, delaying meals on weekends appears to be linked to a higher BMI. Conversely, among individuals with a morning tendency, eating meals later on weekends is associated with higher energetic intake on weekends.

Does time-restricted eating add benefits to calorie restriction? A systematic review

OBJECTIVE

A growing body of evidence has supported the health benefits of extended daily fasting, known as time-restricted eating (TRE); however, whether the addition of TRE enhances the known benefits of calorie restriction (CR) remains unclear.

METHODS

PubMed, Scopus, the Cochrane Library, and Google Scholar were searched through April 2023. This systematic review includes randomized controlled trials (RCTs) that compared CR + TRE with CR alone in energy-matched conditions of at least 8 weeks in duration that assessed changes in body weight and cardiometabolic disease risk factors in adults with overweight and/or obesity.

RESULTS

Seven studies were identified (n = 579). Two studies reported greater weight loss and reductions in diastolic blood pressure with CR + TRE compared with CR alone after 8 to 14 weeks, whereas one study reported greater improvements in triglycerides and glucose tolerance with CR + TRE (3 days/week) compared with CR alone following 26 weeks. One study reported significant increases in homeostatic model assessment of insulin resistance (HOMA-IR) levels with CR + TRE versus CR alone after 8 weeks. There were no statistically significant differences in any other outcome variable between the two interventions.

CONCLUSIONS

The addition of TRE to CR regimens resulted in greater weight loss and improvements in cardiometabolic risk factors in some studies; however, the majority of studies did not find additional benefits.

Association of Nightly Fasting, Meal Frequency, and Skipping Meals with Metabolic Syndrome among Kuwaiti Adults

Mounting evidence suggests that meal timing and frequency are associated with cardiometabolic health by influencing circadian rhythms. However, the evidence is inconsistent and limited, especially in non-Western cultures. This cross-sectional study aims to investigate the association between temporal habits of dietary intake, such as nightly fasting duration and meal frequency, and metabolic syndrome among Kuwaiti adults. A 24-hour recall was used to assess temporal habits of dietary intake. Meal frequency was defined as the number of daily eating episodes. The study included a total of 757 adults aged 20 years and older. The participants' mean age was 37.8 ± 12.3 years. After adjusting for all confounders, higher meal frequency was found to be associated with a lower prevalence of metabolic syndrome in adults (OR, 0.43; 95%CI, 0.19-0.96) and a lower prevalence of elevated triglycerides in men only (OR, 0.23; 95%CI, 0.09-0.60). No association was found between nightly fasting and metabolic syndrome, but a longer fasting duration was associated with a lower prevalence of elevated triglycerides (OR, 0.19; 95%CI, 0.06-0.63). The findings suggest that having frequent meals and longer durations of nightly fasting may help decrease the risk of metabolic syndrome and elevated triglycerides.

Social and circadian rhythm dysregulation and suicide: A systematic review and meta-analysis

This systematic review of 52 studies provides a quantitative synthesis of the empirical literature on social and circadian rhythm correlates of suicidal thoughts and behaviors (STB). Small-to-medium pooled effect sizes were observed for associations between evening chronotype and STB and suicidal ideation (SI), although the pooled effect size diminished when accounting for publication bias. Three studies employed longitudinal designs and suggested eveningness was predictive of future STB, with a small-to-medium effect size. Social rhythm irregularity was also a significant correlate of STB with pooled effect sizes in the medium range. Overall circadian rhythm disruption was not associated with STB, although certain circadian rhythm metrics, including mean daytime activity, circadian rhythm sleep-wake disorder diagnosis, and actigraphy-assessed amplitude were associated with STB. Pooled effect sizes for these indices were in the medium to large range. There is a need for additional longitudinal research on actigraphy-based circadian parameters and objective markers of circadian phase (i.e., dim-light melatonin onset) to gain a clearer understanding of associations of endogenous circadian function and STB beyond that which can be captured via self-report.

Is the Caloric Midpoint Associated with Food Cravings and Food Intake in Pregnant Women?

Objective: The field of chrononutrition suggests that mealtime can influence food intake. Previous studies have linked the caloric midpoint - defined as the time at which 50% of the daily energy is consumed - with different aspects of food consumption. However, its relationship with food craving remains unexplored. This cross-sectional study aimed to investigate the association between caloric midpoint, food craving, and food consumption in pregnant women.Methods: The study comprised 233 pregnant women classified as early eaters (caloric midpoint ≤ 1:00pm) and late eaters (caloric midpoint >1:00pm). Food craving were assessed using Food Craving Trait and State Questionnaires. Energy and nutrient intake, as well as mealtimes, were assessed using a 24-h food recall.Results: No association between caloric midpoint and food craving was found. However, late eaters consumed more calories (2039.47 kcal vs 1843.44 kcal; p < 0.001), carbohydrates (255.06 g vs 211.12 g; p = 0.002), total fat (73.1 g vs 64.8 g; p = 0.003), monounsaturated fat (21.33 mg vs 18.59 mg; p = 0.002) and saturated fat (24.37 mg vs 22.21 mh; p = 0.01) and had higher consumption of calories and macronutrients in the first (calories: 275.63 vs 213.41, p = 0.007; carbohydrate: 170.42 vs 142.54, p = 0.01; total fat: 56.49 vs 50.17, p = 0.04) and second (calories: 213.21 vs 151.59, p = 0.04; carbohydrate: 130.44 vs 96.6, p = 0.04; protein: 15.17 vs 13.71, p = 0.03) afternoon snack, dinner (calories: 576.89 vs 412.4, p < 0.001; carbohydrate: 230.76 vs 169.45, p < 0.001; protein: 80.48 vs 68.9, p = 0.02; total fat: 212.77 vs 147.12, p < 0.001) and late-night snack (calories: 135.75 vs 68.3, p = 0.04; total fat: 13.23 vs 22.45, p = 0.04) than early eaters.Conclusion: Pregnant women who concentrate their meals at later times consumed more calories, macro and micronutrients throughout the day and in the night meals when compared to early eaters.

Differences in nutritional profile by chronotype among 12-h day shift and night shift nurses

Acute care nurses may suffer substantial fatigue if working night shift or if assigned a shift contrasting their preferred sleep-wake patterns, called chronotype. Nurses are at higher risk for diet-related, metabolic diseases compared to other healthcare professionals. Yet, the impact of preferred chronotype and mismatch to assigned shift on nutritional intake and risk for metabolic disease among acute care nurses is unclear. This observational study analyzed dietary data from 52 acute care nurses. Participants completed the revised morningness-eveningness questionnaire which gives a total score between 4 and 26. Lower scores (<12) were flagged as evening type (E-type), higher scores (>17) defined as morning type (M-type), and scores between 12 and 17 were categorized as neither types (N-type). N-type participants were considered chronotype matched when assigned to either shift, whereas E-types were only considered matched if assigned to night shift, and M-types matched only if assigned to day shift. Participants also recorded all dietary intake for 7 d (reflecting a typical workweek) in the MyFitnessPal phone application. Findings indicated that eveningness nurses had markers of MetS, including a significantly larger body mass index and waist circumference than N-types (p < 0.05). E-types also consumed, on average, more calories than other chronotypes (m = 1833.7 kcal), although this was not a statistically significant finding. Mismatched day (n = 7, 13.4%) and night (n = 5, 9.6%) nurses in our sample consumed, on average, more calories (m = 1935.1 kcal, m = 1981.2 kcal, respectively) than matched day (n = 24, 46.2%, m = 1642.6 kcal) or night (n = 16, 30.8%, m = 1599.1 kcal) nurses, although this finding was not statistically significant. Mismatched day nurses consumed significantly less fiber than day matched nurses (median = 10.9 g versus median = 18.5 g, p = 0.04), while night mismatched consumed significantly more fiber compared to night matched (median = 21 g versus median = 12.2 g, p = 0.05) nurses. Participant diets overall did not follow recommendations by the United States Department of Agriculture (USDA), who consumed a higher percentage of calories from saturated fats and a smaller percentage of calories from fiber, habits which increase risk for metabolic syndrome. Further research surrounding nutritional pathways utilizing larger samples is needed to uncover relationships with metabolic syndrome especially for eveningness-type nurses or if working a shift mismatched with preferred chronotype.

Catch-up sleep on free days and body mass index: results from the seventh Korea National Health and Nutrition Examination Survey, 2016

STUDY OBJECTIVES

We aimed to identify the relationship between duration of categorized catch-up sleep on free days (CUS) and measured body mass index (BMI) in adults using the data from the seventh Korean National Health and Nutrition Examination Survey (KNHANES VII), 2016.

METHODS

CUS duration was classified as ≤ 0, > 0-1, > 1-2, and > 2 hours. Being overweight or obese was defined as having a BMI ≥ 25.0 kg/m2 or ≥ 30.0 kg/m2, respectively.

RESULTS

Of 6,382 participants aged 19-80 years in the KNHANES VII survey of 2016, 201 and 583 participants were excluded because of shift-working and insufficient data, respectively. Of 5,598 participants, CUS was observed in 2,274 (44.9%) participants, of which 3,324 (55.1%), 1,043 (19.4%), 724 (14.7%), and 507 (10.8%) had CUS of ≤ 0, > 0-1, > 1-2, and > 2 hours, respectively; the prevalence of obesity was 5.6%, 5.6%, 4.8%, and 6.1%, respectively. The association between BMI and CUS duration showed a significant negative association in the CUS ≤ 0 hours group (beta [95% confidence interval], -0.394 [-0.646, -0.143], P = .002); however, other CUS groups did not show any significant association with BMI (CUS > 0-1 hours: -0.196 [-1.258, 0.865], P = .716; CUS > 1-2 hours, -0.542 [-1.625, 0.541], P = .325; CUS > 2 hours, -0.113 [-0.459, 0.233], P = .519).

CONCLUSIONS

Our findings provide an understanding of the relationship between CUS and BMI and can serve as an instructive basis for the management of BMI.

CITATION

Lee HJ, Cho S, Lee SH, Kim SJ, Kim KM, Chu MK. Catch-up sleep on free days and body mass index: results from the seventh Korea National Health and Nutrition Examination Survey, 2016. J Clin Sleep Med. 2024;20(1):39-47.

Sleep, activity, and diet in harmony: unveiling the relationships of chronotype, sleep quality, physical activity, and dietary intake

Introduction

This cross-sectional study aims to explore the intricate relationships among chronotype, sleep quality, physical activity, and dietary intake in a diverse cohort of 3,072 (50.2% female) participants residing in İstanbul, Türkiye.

Methods

This study utilized established measurement tools, including the Morningness-Eveningness Questionnaire (MEQ) to assess chronotype, the Pittsburgh Sleep Quality Index (PSQI) to evaluate sleep quality, the International Physical Activity Questionnaire Short Form (IPAQ-SF) to measure physical activity, and a 24-h dietary recall method to assess dietary intake.

Results

The findings of this study revealed compelling associations. Firstly, a robust association was observed between sleep quality and chronotype (OR: 2.265; 95% CI: 1.954-2.626; p < 0.001) as well as physical activity (OR: 0.836; 95% CI: 0.750-0.932; p = 0.002). Specifically, evening chronotypes are more likely to have poor sleep quality, while highly active individuals tend to report lower sleep quality. Transitioning from inactivity to high activity was associated with a 16.4% increase in the odds of transitioning from normal to poor sleep, while a shift from an evening to a morning chronotype was linked to a substantial 126.5-fold increase in the odds of moving from poor to normal sleep. Additionally, morning chronotypes also display distinctive dietary patterns, characterized by higher energy, protein, and fat intake, and reduced carbohydrate intake. Poor sleep quality is associated with increased energy and macronutrient consumption.

Discussion

These findings underscore the intricate relationships of chrononutrition within the context of sleep quality, physical activity, and dietary choices. The study underscores the significance of personalized interventions to effectively address specific health behaviors, highlighting the complexity of chrononutrition's role in promoting overall health and wellbeing.

Spent coffee grounds and its antioxidant dietary fiber promote different colonic microbiome signatures: Benefits for subjects with chronodisruption

Chronodisruption, commonly displayed by people living with obesity (PLO), is linked to colonic microbiota dysbiosis, and may increase the risk of many chronic non-communicable diseases, whereas dietary interventions-called chrononutrition may mitigate it. We evaluated the in vitro effects of spent coffee grounds (SCG), and their antioxidant dietary fiber (SCG-DF) on the colonic microbiota of an obese donor displaying dysbiosis and chronodisruption. Basal microbiota pattern was associated with an increased risk of non-communicable chronic diseases. Both samples decrease species richness and increase microbiota diversity (p < 0.05; Chao and Shannon index, respectively), positively enhancing Firmicutes/Bacteroidetes index (SCG, p < 0.04; SCG-DF, p < 0.02). SCG and SCG-DF modulated the microbiota, but SCG-DF induced greater changes, significantly increasing. p_Actonobacterias (SCG p < 0.04; SCG-DF, p < 0.02), and reducing g_Alistipes; s_putredinis, g_Prevotella;s_copri. The highest increase was displayed by p_Proteobacteria (f_Desulfovibrionaceae and f_Alcanigenaceae, p < 0.05), while g_Haemophilus; s_parainfluenzae decreased (p < 0.05). However, neither SCG nor SCG-DF modulated g_Alistipes (evening-type colonic microbial marker) beneficially. SCG and SCG-DF reduced (p < 0.05) g_Lachnospira, a microbial evening-type marker, among other microbial populations, of an obese donor displaying chronodisruption and dysbiosis. SCG and SCG-DF displayed a prebiotic effect with the potential to mitigate diseases linked to chronodisruption.

Temporal associations between nightly sleep with daytime eating and activity levels in free-living young adults

STUDY OBJECTIVES

This study aimed to quantify the temporal associations between nightly sleep quantity and timing with daytime eating behavior and activity levels in free-living (i.e. non-experimental) settings.

METHODS

Generally healthy young adults (N = 63; 28.9 ± 7.1 years) completed concurrent sleep (wrist actigraphy), eating (photo-assisted diet records), and activity (waist actigraphy) assessments over 14 days. Multilevel models quantified the associations between nightly sleep (total sleep time, timing of sleep and wake onset) with next-day eating behavior (diet quality, caloric intake, timing of eating onset/offset, eating window duration) and activity levels (total physical activity, sedentary time). Associations in the reverse direction (i.e. eating and activity predicting sleep) were explored. Models adjusted for demographic and behavioral confounders and accounted for multiple testing.

RESULTS

At within- and between-subject levels, nights with greater-than-average total sleep time predicted a shorter eating window the next day (all p ≤ 0.002). Later-than-average sleep and wake timing predicted within- and between-subject delays in next-day eating onset and offset, and between-subject reductions in diet quality and caloric intake (all p ≤ 0.008). At within- and between-subject levels, total sleep time was bidirectionally, inversely associated with sedentary time (all p < 0.001), while later-than-average sleep and wake timing predicted lower next-day physical activity (all p ≤ 0.008).

CONCLUSIONS

These data underscore the complex interrelatedness between sleep, eating behavior, and activity levels in free-living settings. Findings also suggest that sleep exerts a greater influence on next-day behavior, rather than vice versa. While testing in more diverse samples is needed, these data have potential to enhance health behavior interventions and maximize health outcomes.

The Relationship between Breakfast and Sleep and Cardiovascular Risk Factors

Despite extensive research on the individual effects of breakfast and sleep on health outcomes, there has been limited investigation into their combined effects. We aimed to evaluate the relationship between breakfast-eating behavior and sleep timing on cardiovascular disease (CVD) risk factors. A total of 16,121 participants (6744 men and 9377 women) aged 19 years or older were selected from the Korea National Health and Nutrition Examination Surveys (2016-2018, 2021). We classified participants into four groups: early sleep + regular breakfast eaters (group 1), late sleep + regular breakfast eaters (group 2), early sleep + infrequent breakfast eaters (group 3), and late sleep + infrequent breakfast eaters (group 4). In men, group 4 had a lower prevalence of obesity than group 1 (OR 0.78, 95%CI 0.62-0.97), and groups 2, 3, and 4 had a higher prevalence of metabolic syndrome (MetS) than group 1 (OR 1.43, 1.62, and 1.47, respectively). In women, group 4 had a lower prevalence of dyslipidemia than group 1 (OR 0.59, 95%CI 0.44-0.80), and group 2 had a higher prevalence of MetS than group 1 (OR 1.24, 95%CI 1.03-1.50). The combination of skipping breakfast and late sleep timing was associated with the higher prevalence of MetS particularly in men. Moreover, the relationship between breakfast and sleep timing on CVD risk factors differed by sex and age group.

The prevalence of temporomandibular disorder and temporomandibular morphology among diverse chronotype profiles

This study investigates the influence of chronotype on the prevalence of temporomandibular joint disorders (TMD) and the morphology of temporomandibular joint (TMJ). According to the Morningness-Eveningness Questionnaire-Self-Assessment, the participants were divided into morning group (n = 30), intermediate group (n = 83), and evening group (n = 30). Thirty participants were randomly selected from the intermediate group for subsequent examination and measurements. The morphology of TMJs was investigated using questionnaire and clinical examination form in Diagnostic Criteria for Temporomandibular Disorder. Meanwhile, the morphological results of TMJs were measured from cone-beam computed tomography images. The prevalence rate of TMD in the morning group (23%) was significantly lower than that in the intermediate group (56.7%), while there was no difference between the evening (53.4%) and intermediate groups. As to morphological measurements, there was no significant difference among three groups in mediolateral width of condylar process, anteroposterior width of condylar process, radius of condyle, medial joint space, lateral joint space, condylar stress angle, horizontal condylar inclination, width of glenoid fossa, depth of glenoid fossa, and posterior joint space, while there was a significant difference in horizontal condylar angle (p = 0.00490), articular eminence inclination (p < .0001), anterior joint space (p = 0.0163), and superior joint space (p = 0.0004). The morphology of TMJ in the morning group was better than that in the evening and intermediate groups. An association was found between TMD prevalence, temporomandibular morphology, and chronotype.

Chronotype is associated with addiction-like eating behavior, mindful eating and ultra-processed food intake among undergraduate students

This study aimed to investigate the relationships between chronotype and addiction-like eating behavior, mindful eating and ultra-processed food consumption among undergraduate students. Specific and validated scales were used in order to evaluate chronotype, addiction-like eating behavior and mindful eating (N = 605). Dietary intake was determined by food frequency questionnaire and percentage energy from ultra-processed food was calculated. Self-reported weights and heights were obtained from the participants. Mean scores of scales, social jetlag, energy intake, ultra-processed food intake and BMI were compared by chronotypes. Associations between chronotype, addiction-like eating behavior, mindful eating, ultra-processed food consumption and BMI were determined by Pearson's test. The relationships between chronotype and addiction-like eating behavior, mindful eating and ultra-processed food intake were assessed by linear regression models and adjusted for sex, BMI, energy intake, season, smoking and alcohol consumption. Evening-type participants had higher scores of social jetlag (2.01 ± 0.09), appetitive drive (26.02 ± 0.63), low dietary control (20.50 ± 0.41), addiction-like eating behavior (46.52 ± 0.85), lower scores of recognition (21.91 ± 0.43) and higher percentage energy from ultra-processed food (32.24 ± 1.26%). Chronotype score showed negative associations with addiction like eating behavior (β=-0.247, p < 0.001) and ultra-processed food consumption (β=-0.247, p < 0.001), and a positive association with recognition (β = 0.124, p < 0.001). Results suggest that chronotype is inversely associated with addiction-like eating behavior and ultra-processed food consumption, and positively associated with mindful eating among undergraduate students.

Chronotype, Unhealthy Lifestyle, and Diabetes Risk in Middle-Aged U.S. Women : A Prospective Cohort Study

BACKGROUND

Evening chronotype may promote adherence to an unhealthy lifestyle and increase type 2 diabetes risk.

OBJECTIVE

To evaluate the role of modifiable lifestyle behaviors in the association between chronotype and diabetes risk.

DESIGN

Prospective cohort study.

SETTING

Nurses' Health Study II.

PARTICIPANTS

63 676 nurses aged 45 to 62 years with no history of cancer, cardiovascular disease, or diabetes in 2009 were prospectively followed until 2017.

MEASUREMENTS

Self-reported chronotype using a validated question from the Morningness-Eveningness Questionnaire. The lifestyle behaviors that were measured were diet quality, physical activity, alcohol intake, body mass index (BMI), smoking, and sleep duration. Incident diabetes cases were self-reported and confirmed using a supplementary questionnaire.

RESULTS

Participants reporting a "definite evening" chronotype were 54% (95% CI, 49% to 59%) more likely to have an unhealthy lifestyle than participants reporting a "definite morning" chronotype. A total of 1925 diabetes cases were documented over 469 120 person-years of follow-up. Compared with the "definite morning" chronotype, the adjusted hazard ratio (HR) for diabetes was 1.21 (CI, 1.09 to 1.35) for the "intermediate" chronotype and 1.72 (CI, 1.50 to 1.98) for the "definite evening" chronotype after adjustment for sociodemographic factors, shift work, and family history of diabetes. Further adjustment for BMI, physical activity, and diet quality attenuated the association comparing the "definite evening" and "definite morning" chronotypes to 1.31 (CI, 1.13 to 1.50), 1.54 (CI, 1.34 to 1.77), and 1.59 (CI, 1.38 to 1.83), respectively. Accounting for all measured lifestyle and sociodemographic factors resulted in a reduced but still positive association (HR comparing "definite evening" vs. "definite morning" chronotype, 1.19 [CI, 1.03 to 1.37]).

LIMITATIONS

Chronotype assessment using a single question, self-reported data, and homogeneity of the study population.

CONCLUSION

Middle-aged nurses with an evening chronotype were more likely to report unhealthy lifestyle behaviors and had increased diabetes risk compared with those with a morning chronotype. Accounting for BMI, physical activity, diet, and other modifiable lifestyle factors attenuated much but not all of the increased diabetes risk.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Seasonal and Regional Differences in Eating Times in a Representative Sample of the Brazilian Population

Human food intake and its timing are a complex behavior that can be influenced by a variety of factors, some of which may vary from season to season or from region to region. In this study, our aim was to investigate the seasonal variation in food intake times, with a particular focus on how these may vary across different regions of a country. We conducted an analysis of data from 20,622 adults from the National Household Budget Survey (POF-IBGE), encompassing complete food diaries collected from individuals residing in Brazil, and thereby ensuring representation across different latitudes. Each participant's daily food intake was reported for two non-consecutive days at different times in the same week using food diaries. An ANOVA revealed a later food intake time in the evening in high-latitude regions compared to low-latitude regions. The Sidak post-hoc test showed a significant interaction effect between region and season, demonstrating a pattern of early First Intake Time and Eating Midpoint in the Northeast region during spring/summer. Additionally, we observed an independent effect of the region, as early food intake times were found in low-latitude regions. These findings offer a basis for discussing food intake times among individuals living in different regions located on distinct latitudes.

Differences in Dietary Intake, Eating Occasion Timings and Eating Windows between Chronotypes in Adults Living with Type 2 Diabetes Mellitus

Chronotype studies investigating dietary intake, eating occasions (EO) and eating windows (EW) are sparse in people with type 2 Diabetes mellitus (T2DM). This analysis reports data from the CODEC study. The Morningness-Eveningness questionnaire (MEQ) assessed chronotype preference. Diet diaries assessed dietary intake and temporal distribution. Regression analysis assessed whether dietary intake, EW, or EO differed by chronotype. 411 participants were included in this analysis. There were no differences in energy, macronutrient intake or EW between chronotypes. Compared to evening chronotypes, morning and intermediate chronotypes consumed 36.8 (95% CI: 11.1, 62.5) and 20.9 (95% CI: -2.1, 44.1) fewer milligrams of caffeine per day, respectively. Evening chronotypes woke up over an hour and a half later than morning (01:36 95% CI: 01:09, 02:03) and over half an hour later than intermediate chronotypes (00:45 95% CI: 00:21; 01:09. Evening chronotypes went to sleep over an hour and a half later than morning (01:48 95% CI: 01:23; 02:13) and an hour later than intermediate chronotypes (01:07 95% CI: 00:45; 01:30). Evening chronotypes' EOs and last caffeine intake occurred later but relative to their sleep timings. Future research should investigate the impact of chronotype and dietary temporal distribution on glucose control to optimise T2DM interventions.

Chronotype and Cardiometabolic Parameters in Patients with Bipolar Disorder: Preliminary Findings

Cardiometabolic alterations are very common in bipolar disorder (BD). The aim of this study was to investigate the relationship between chronotype and cardiometabolic parameters in patients with a primary diagnosis of BD. This study is an observational clinical investigation including 170 subjects consecutively admitted to the Psychiatric Inpatient Unit of the IRCCS Ospedale Policlinico San Martino (Genoa, Italy), recruited over a period of 48 months. A psychometric tool assessing chronotype was administered and blood tests were performed. Furthermore, the atherogenic coefficient ((total cholesterol-HDL cholesterol)/HDL cholesterol), and Castelli risk index-I (total cholesterol/HDL cholesterol) and -II (LDL cholesterol/HDL cholesterol) were calculated. Patients with BD and an eveningness chronotype showed a higher body mass index, total and low-density lipotrotein cholesterol compared to patients with BD and an intermediate or morning chronotype. Furthermore, the Atherogenic Coefficient and Castelli Risk-Index I-II were found to be higher in bipolar patients with an evening chronotype. The role of chronotype in the development of obesity and cardiovascular risk is, therefore, a relationship worth being investigated, especially in the context of BD, to ameliorate the clinical and therapeutic approach, aiming at increasing the quality of life and reducing the mortality.

Interventions to Address Cardiovascular Risk in Obese Patients: Many Hands Make Light Work

Obesity is a growing public health epidemic worldwide and is implicated in slowing improved life expectancy and increasing cardiovascular (CV) risk; indeed, several obesity-related mechanisms drive structural, functional, humoral, and hemodynamic heart alterations. On the other hand, obesity may indirectly cause CV disease, mediated through different obesity-associated comorbidities. Diet and physical activity are key points in preventing CV disease and reducing CV risk; however, these strategies alone are not always sufficient, so other approaches, such as pharmacological treatments and bariatric surgery, must support them. Moreover, these strategies are associated with improved CV risk factors and effectively reduce the incidence of death and CV events such as myocardial infarction and stroke; consequently, an individualized care plan with a multidisciplinary approach is recommended. More precisely, this review explores several interventions (diet, physical activity, pharmacological and surgical treatments) to address CV risk in obese patients and emphasizes the importance of adherence to treatments.

Chronotype as a predictor of weight loss and body composition improvements in women with overweight or obesity undergoing a very low-calorie ketogenic diet (VLCKD)

BACKGROUND & AIM

Recent studies reported that chronotype play a role in the development of metabolic comorbidities and in determining dietary habits in obesity. However, little is known if chronotype could predict the efficacy of nutritional approaches for obesity. The aim of this study was to investigate whether chronotype categories can have a role in determining the efficacy of very low-calorie ketogenic diet (VLCKD) in terms of weight loss and changes of body composition in women with overweight or obesity.

METHODS

In this retrospective study we analyzed data from 248 women (BMI 36.03 ± 5.20 kg/m2, aged 38.76 ± 14.05 years) clinically referred for weight loss and who completed a VLCKD program. In all women, we assessed anthropometric parameters (weight, height, and waist circumference), body composition and phase angle (through bioimpedance analysis, Akern BIA 101) at the baseline and after 31 days of active phase of VLCKD. Chronotype score was assessed using Morningness-Eveningness questionnaire (MEQ) at baseline.

RESULTS

After 31 days of active phase of VLCKD all enrolled women experienced significant weight loss (p < 0.001) and reduction of BMI (p < 0.001), waist circumference (p < 0.001), fat mass (kg and %) (p < 0.001), and free fat mass (kg) (p < 0.001). Women with evening chronotype experienced significantly less weight loss (p < 0.001) and reduced fat mass (kg and %) (p < 0.001), increased fat free mass (kg and %) (p < 0.001) and phase angle (p < 0.001) than women with morning chronotype. In addition, chronotype score correlated negatively with percentage changes in weight (p < 0.001), BMI (p < 0.001), waist circumference (p < 0.001) and fat mass (p < 0.001) and positively with fat free mass (p < 0.001) and phase angle (p < 0.001) from baseline to the 31st day of active phase of VLCKD. Using a linear regression model, chronotype score (p < 0.001) was the main predictors of weight loss achieved with VLCKD.

CONCLUSION

Evening chronotype is associated with a lower efficacy in terms of weight loss and improvements of body composition after VLCKD in obesity.

Breakfast Frequency and Sleep Quality in College Students: The Multiple Mediating Effects of Sleep Chronotypes and Depressive Symptoms

Sleep disorders, which are prominent problems among college students, may be associated with skipping breakfast. Therefore, we aimed to explore the role of sleep chronotypes and depressive symptoms as mediators in the relationship between breakfast frequency and sleep quality. A cross-sectional survey enrolling random samples of 712 college students was conducted by the Questionnaire Star online platform. Statistical description and correlation analysis were performed by SPSS 25.0, and a chain mediation test was performed by model 6 in PROCESS 3.5. The result of the article demonstrated that breakfast frequency can affect sleep quality through two mediating pathways: ① sleep chronotypes, with a mediating effect of 32%; and ② depressive symptoms, with a mediating effect of 52.4%. However, the chain mediating effects of sleep chronotypes and depressive symptoms was not significant, and neither was the direct effect of breakfast frequency on sleep quality. Breakfast frequency can indirectly affect sleep quality by adjusting sleep chronotypes and depressive symptoms. Regular breakfast can increase morning and intermediate sleep chronotypes, reduce depressive symptoms, and thus improve sleep quality.

Working Memory in Overweight Boys during Physical Education Classes

This study examined the effect of small-sided football games (SSFG) and small-sided Ultimate Frisbee games (SSUFG) on working memory, response times, and feeling mood of boys with overweight. Twenty-eight boys (age 12.23 ± 1.58 years) participated in two trials during physical education lessons (20-min SSFG and 20-min SSUFG) in a counterbalanced, randomized crossover design. The response times and feeling mood were measured for all participants post-exercise through the Sternberg paradigm and feeling scale. For the response times, the paired samples t-test revealed a significantly better reaction time after SSUFG at the "One item level" of the Sternberg paradigm (p = 0.014, Hedges' g = 0.27, small effect) and (p = 0.010, Hedges' g = 0.74, medium effect), at "Three item level" (p = 0.000106, Hedges' g = 1.88, very large effect). The SSFG also showed vigor at the "Five item level" (p = 0.047, Hedges' g = 0.61, medium effect). For the feeling mood, the feeling score was significantly higher after the SSUFG session than the SSFG session and the increase in feeling scores observed after switching from SSFG to SSUFG was significantly different (p < 0.001) from the decrease observed in feeling scores after switching from SSUFG to SSFG. Therefore, the results of the study allow the teacher to introduce new sports and reflect on the motor tasks he or she proposes for boys with overweight during physical education classes.

How Fast Do “Owls” and “Larks” Eat?

Chronotype is a reflection of an individual’s preference for sleeping, eating and activity times over a 24 h period. Based on these circadian preferences, three chronotype categories have been identified: morning (MC) (lark), intermediate (IC) and evening (EC) (owl). Chronotype categories have been reported to influence dietary habits; subjects with EC are more prone to follow unhealthy diets. In order to better characterize the eating habits of subjects with obesity belonging to three different chronotype categories, we investigated eating speed during the three main meals in a population of subjects with overweight/obesity. For this purpose, we included 81 subjects with overweight/obesity (aged 46.38 ± 16.62 years; BMI 31.48 ± 7.30 kg/m2) in a cross-sectional, observational study. Anthropometric parameters and lifestyle habits were studied. Chronotype score was assessed using the Morningness–Eveningness questionnaire (based on their scores, subjects were categorized as MC, IC or EC). To investigate the duration of main meals, a dietary interview by a qualified nutritionist was conducted. Subjects with MC spend significantly more time on lunch than subjects with EC (p = 0.017) and significantly more time on dinner than subjects with IC (p = 0.041). Furthermore, the chronotype score correlated positively with the minutes spent at lunch (p = 0.001) and dinner (p = 0.055, trend toward statistical significance). EC had a fast eating speed and this, in addition to better characterizing the eating habits of this chronotype category, could also contribute to the risk of developing obesity-related cardiometabolic diseases.

Beyond sleep: A multidimensional model of chronotype

Chronotype can be defined as an expression or proxy for circadian rhythms of varied mechanisms, for example in body temperature, cortisol secretion, cognitive functions, eating and sleeping patterns. It is influenced by a range of internal (e.g., genetics) and external factors (e.g., light exposure), and has implications for health and well-being. Here, we present a critical review and synthesis of existing models of chronotype. Our observations reveal that most existing models and, as a consequence, associated measures of chronotype have focused solely or primarily on the sleep dimension, and typically have not incorporated social and environmental influences on chronotype. We propose a multidimensional model of chronotype, integrating individual (biological and psychological), environmental and social factors that appear to interact to determine an individual's true chronotype with potential feedback loops between these factors. This model could be beneficial not only from a basic science perspective but also in the context of understanding health and clinical implications of certain chronotypes as well as designing preventive and therapeutic approaches for related illnesses.

Highlighting the importance of healthy sleep patterns in the risk of adult asthma under the combined effects of genetic susceptibility: a large-scale prospective cohort study of 455 405 participants

BACKGROUND

Individuals with asthma usually have comorbid sleep disturbances; however, whether sleep quality affects asthma risk is still unclear. We aimed to determine whether poor sleep patterns could increase the risk of asthma and whether healthy sleep patterns could mitigate the adverse effect of genetic susceptibility.

METHODS

A large-scale prospective study was performed in the UK Biobank cohort involving 455 405 participants aged 38-73 years. Polygenic risk scores (PRSs) and comprehensive sleep scores, including five sleep traits, were constructed. A multivariable Cox proportional hazards regression model was used to investigate the independent and combined effects of sleep pattern and genetic susceptibility (PRS) on asthma incidence. Subgroup analysis across sex and sensitivity analysis, including a 5-year lag, different covariate adjustments and repeat measurements were performed.

RESULTS

A total of 17 836 individuals were diagnosed with asthma during over 10 years of follow-up. Compared with the low-risk group, the HRs and 95% CIs for the highest PRS group and the poor sleep pattern group were 1.47 (95% CI: 1.41 to 1.52) and 1.55 (95% CI: 1.45 to 1.65), respectively. A combination of poor sleep and high genetic susceptibility led to a twofold higher risk compared with the low-risk combination (HR (95% CI): 2.22 (1.97 to 2.49), p<0.001). Further analysis showed that a healthy sleep pattern was associated with a lower risk of asthma in the low, intermediate and high genetic susceptibility groups (HR (95% CI): 0.56 (0.50 to 0.64), 0.59 (0.53 to 0.67) and 0.63 (0.57 to 0.70), respectively). Population-attributable risk analysis indicated that 19% of asthma cases could be prevented when these sleep traits were improved.

CONCLUSIONS

Individuals with poor sleep patterns and higher genetic susceptibility have an additive higher asthma risk. A healthy sleep pattern reflected a lower risk of asthma in adult populations and could be beneficial to asthma prevention regardless of genetic conditions. Early detection and management of sleep disorders could be beneficial to reduce asthma incidence.

The relationship between chronotype and obesity: A systematic review

Referring to the hours during a day when a person's physical and cognitive functions are active, the chronotype indicates the differences in individual preferences in sleep timing and other behaviors. The fact that the evening chronotype has been associated with adverse health outcomes has raised the issue of relationship between chronotype and obesity. This study aims to synthesize the evidence regarding the relationship between chronotype and obesity. As part of the study, the PubMed, OVID-LWW, Scopus, Taylor & Francis, ScienceDirect, MEDLINE Complete, Cochrane Library and ULAKBIM databases were screened for the articles published between January 01, 2010 and December 31, 2020. The quality of each study was assessed independently by the two researchers using the "Quality Assessment Tool for Quantitative Studies." Upon evaluating the screening results, a total of seven studies, one of high quality and six of medium quality, were included in the systematic review. The rate of the minor allele (C) genes, which have been associated with obesity, and SIRT1-CLOCK genes, which have an additional effect in favor of resistance against weight loss, is higher in individuals of evening chronotype, and such individuals have been observed to have significantly higher resistance to weight loss. The evening chronotype individuals have been associated with a higher homeostasis model assessment (HOMA) value, higher plasma ghrelin levels, and a tendency toward a higher body mass index (BMI). The evening chronotypes have been reported to adhere less to a healthy diet and have more unhealthy behaviors and eating patterns. A diet adjusted to the chronotype has been seen to be more effective than conventional hypocaloric diet therapy in terms of anthropometric parameters. Most people who eat their main meals late are of evening chronotype, and such people have been determined to lose significantly less weight than those who eat early. It has been shown that bariatric surgery is less effective in weight loss in evening chronotype patients than in morning chronotype patients. The evening chronotypes are less successful in adapting to weight loss treatments and long-term weight control than the morning chronotypes.

Time-related meal patterns and breakfast quality in a sample of Iranian adults

BACKGROUND

Some evidence shows that meal timing is associated with diet quality. We aimed to investigate the relationship between meal timing and breakfast quality in a sample of Iranian adults.

METHODS

This cross-sectional study was conducted on 850 men and women living in Tehran, Iran. Dietary data was recorded by three non-consecutive 24-h dietary recalls. The Breakfast Quality Index (BQI) was calculated. Time-related meal patterns included the interval between the first and last meal (eating and fasting window), frequency of meals, length of sleep, and time of first and last eating occasion. The multiple linear regression analysis was used to identify the relationships between time-related meal patterns and BQI.

RESULTS

The mean (95% CI) of BQI was 4.52 (4.45-4.65) and the maximum was 8. Bread, cheese, vegetables, fruits, energy, and carbohydrate intake showed positive associations with BQI scores. Longer fasting time showed a positive association with fruits (β (CI 95%)) (0.11 (0.0003-0.005), and vegetable consumption (0.12 (0.009-0.07)) and BQI score (0.39 (0.001-0.06)). Time of first eating occasions indicated a negative association with protein and fat intake and BQI score. Time of last eating occasions showed a positive association with vegetables consumption and BQI score. The longer length of sleep was associated with a higher BQI score. The frequency of meals was significantly and positively related to energy and macronutrients intake and BQI.

CONCLUSION

Earlier first and last meal, longer sleep length, longer fasting window, and a greater meal frequency were associated with a better breakfast quality.

The association of meal-specific food-based dietary inflammatory index with cardiovascular risk factors and inflammation in a sample of Iranian adults

BACKGROUND

This study aimed to evaluate the association of meals-specific food-based dietary inflammatory index (FDII), with cardiovascular (CVD) risk factors and inflammation among Iranian adults.

METHODS

In this cross-sectional study, we recruited 816 participants living in Tehran via two-staged cluster sampling. Three non-consecutive 24-h dietary recalls (two working days and one day off) were obtained from individuals to specify the main meals and meal-specific FDIIs. Anthropometric measures were done. Insulin and high-sensitivity c-reactive protein (hs-CRP) were measured. Multiple linear regressions were used to investigate the association of FDII with Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), hs-CRP, Triglyceride Glucose Index (TyG), and Lipid Accumulation Product Index (LAP).

RESULTS

The range of FDIIs for breakfast, lunch, and dinner were (-2.47,1.98), (-2.66,3.23) and (-4.09,3.13) in order, and the mean age was 42.2 ± 10.5 years. We found that there was no significant association between FDII and hs-CRP level in the three meals (β = -0.003; 95% CI: -0.030, 0.025 for breakfast,β = -0.020; 95% CI: -0.041, 0.001 for lunch, and β = 0.006; 95% CI: -0.016, 0.028 for dinner) after adjusting for age, sex, education, occupation, maritage, physical activity, smoking, morningness-eveningness score, energy, body mass index, and other FDIIs. Also, we found no significant association between breakfast, lunch, and dinner-specific FDII and HOMA-IR (β = -0.368, -0.223, 0.122), TyG index (β = -0.009, 0.060, -0.057) and LAP (β = 2.320, -0.278, -0.297).

CONCLUSIONS

We found no associations between meal-based FDII scores and CVD and inflammation. Further research of prospective nature is needed to confirm these findings.

Adaptation and Validation of the Malay-Chrononutrition Profile Questionnaire to Assess Chrononutrition Behavior of Young Adults in Malaysia

Background

Chrononutrition studies how biological rhythms and nutrition are associated with human health. However, a validated assessment in Malaysia is still absent.

Objectives

To create a translation of the Chrononutrition Profile Questionnaire (CPQ), test its validity and reliability, and determine the general chrononutrition behaviors among Malaysian young adults.

Methods

The Malay-CPQ was distributed to respondents through online platforms (n = 110), and data analyses were performed. The data were analyzed for their validity using content validity index (CVI) and face validity index (FVI), whereas intraclass correlation coefficient (ICC) was used to determine test-retest reliability.

Results

Our results showed both CVI and FVI of Malay-CPQ were 1, indicating excellent content translation, while the ICC values ranged from moderate to good (0.50-0.90). The Cronbach α values for all items ranged from moderate to good (0.50-0.90), and the Bland-Altman analysis showed a P value >0.05, indicating agreement of the item between repeated measurements. The chrononutrition behaviors among Malaysian young adults presented fair to good scores for all behavior patterns: eating window, breakfast skipping, evening eating, night eating, and largest meal, except evening latency, being mostly at the poor score (>80% responses).

Conclusions

The Malay-CPQ is a valid and reliable tool to assess the Malaysian chrononutrition profile. However, further testing on Malay-CPQ should be conducted in a different setting in Malaysia for cross-validation studies.

Morning individuals in Saudi Arabia have higher self-regulation of eating behavior compared to evening types

Chronotype is a manifestation of an individual's circadian system, which can be presented as a preference for morningness or eveningness. Evening chronotype has been linked to unhealthy dietary habits. These habits are partially from poor self-regulation of eating behavior (SREB). SREB is a goal-directed process that helps resist food temptation and achieve desired dietary outcomes. It is unclear whether chronotype is associated with SREB. This study aims to investigate the association between chronotypes and SREB. A total of 599 adults (18-50 years) enrolled in this cross-sectional study. Participants received an online questionnaire that collected sociodemographic, anthropometrics, chronotype through the validated reduced Morningness-Eveningness Questionnaire (rMEQ) and SREB using the SREB Questionnaire. ANOVA, Chi-square and multivariate logistic regression were used. In adjusted models, morning types had 85% higher SREB compared to evening types (p = 0.003, OR = 1.85). Evening types found fried foods (p = 0.003), chips (p = 0.005) and French fries (p = 0.018) more tempting than morning types. These findings show a link between chronotype and SREB. Strategies focusing on SREB may help evening types improve dietary habits. Further studies are required to clarify the underlying mechanisms for these associations. This may have important implications for lifestyle and behavioral change policy.

Effects of Time-Restricted Feeding and Ramadan Fasting on Body Weight, Body Composition, Glucose Responses, and Insulin Resistance: A Systematic Review of Randomized Controlled Trials

Time-restricted feeding (TRF) and Ramadan fasting (RF) have been recently associated with several health outcomes. However, it is not yet clear if they are superior to existing treatments in terms of glucose metabolism, insulin action, and weight loss. This review aims to summarize the current data on the effects of these regimes on body weight, body composition, and glycemia. An electronic search was conducted in PUBMED and SCOPUS databases up to August 2022. Twenty-four records met the inclusion criteria and underwent a risk-of-bias assessment. The main outcomes were: (a) TRF may result in moderate weight loss in individuals with overweight/obesity; when TRF is combined with caloric restriction, weight loss is >5% of the initial body weight, (b) 14 h of fasting may be as effective as 16 h in terms of weight loss, and (c) TRF may lead to improved insulin sensitivity and glycemic responses/variability throughout the day in individuals with overweight/obesity. Concerning RF, only two studies were available and thus, conclusions were not drawn. TRF may be an effective nutritional approach for weight loss, and the amelioration of glycemic control and insulin sensitivity in individuals with overweight/obesity. However, more long-term, well-designed studies are needed.

Prediction of Dropout in a Randomized Controlled Trial of Adjunctive Light Treatment in Patients with Non-Seasonal Depression and Evening Chronotype

The current study examined the possible predictors of dropout during a five-week light treatment (LT) with a gradual advance protocol in 93 patients with unipolar non-seasonal depression and evening chronotypes by comparing their clinical characteristics and performing a logistic regression analysis. Nineteen out of ninety-three (20%) subjects (80% female, 46.5 ± 11.7 years old) dropped out during the 5-week light treatment. Treatment non-adherence (i.e., receiving LT for less than 80% of the prescribed duration) over the first treatment week predicted a five-fold increase in risk of dropout during light therapy (OR: 5.85, CI: 1.41–24.21) after controlling for potential confounders, including age, gender, treatment group, rise time at the baseline, patient expectation, and treatment-emergent adverse events. There is a need to incorporate strategies to enhance treatment adherence and retention in both research and clinical settings. Chinese clinical trial registry (ChiCTR-IOR-15006937).