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

The Association Between Midpregnancy Food Intake Timing Patterns and Gestational Weight Gain

Background: This article aims to characterize midpregnancy food timing profiles and examine their association with gestational weight gain (GWG). Materials and Methods: This secondary data analysis of a randomized controlled trial of two gestational diabetes screening approaches included 641 individuals with primary exposures and outcomes data. Food timing indicators (i.e., first and last eating episode time, caloric midpoint time, and the total eating window) were assessed using two 24-hour dietary recalls conducted in midpregnancy. Latent profile analysis was used to identify distinct food timing profiles based on these indicators. Regression analyses explored the associations between individual food intake timing indicators, food timing profiles, and GWG. Results: We identified four food timing profiles: extended window eating (n = 133; earliest first eating episode and the longest eating window), restricted window eating (n = 120; latest first eating episode and shortest eating window), early eating (n = 188; earliest caloric midpoint), and typical eating (n = 200; food intake aligning with the sample median). Participants with a restricted window eating profile (vs. typical eating profile) had an increased risk of insufficient GWG (unadjusted relative risk [RR] = 1.85, 95% confidence interval [CI] 1.12, 3.05). Each hour increase in the timing of the last eating episode was associated with 0.39 kg (0.03, 0.75) higher GWG. Both associations were attenuated in adjusted models and no longer statistically significant in adjusted models. Conclusions: We identified four distinct midpregnancy food timing profiles, but these profiles were not independently associated with GWG. These findings suggest that midpregnancy food timing may not play a major role in GWG.

Association of meal timing with adiposity measures and gut microbiome characteristics in a cohort study: the Hispanic Community Health Study/Study of Latinos

BACKGROUND

Time-restricted eating may help control weight through caloric restriction, circadian rhythm, or influence on the gut microbiome (GMB). Physical activity (PA) also plays a role, as people with a longer eating window (EW, time between first and last daily intake) may be more active. The associations between meal timing, adiposity, PA, sedentary behavior (SB), and GMB characteristics are of interest in Hispanic/Latino persons, who experience a high burden of cardiometabolic diseases.

OBJECTIVES

We explored the relationship of EW with energy intake and accelerometer-measured activity and assessed whether a longer EW and later midpoint of intake (MOI, midpoint time of intake) are associated with adiposity and GMB differences in Hispanic/Latino adults.

METHODS

Using data from the prospective Hispanic Community Health Study/Study of Latinos (n = 11,778 participants with valid 24-h dietary recall and accelerometer data, no unplanned weight loss, and BMI ≥ 18.5 kg/m2; n = 1925 with GMB data), we explored the relationship between EW, SB, and energy intake. We used multivariable linear regression models to study the relationship between EW or MOI and adiposity measures and GMB characteristics, adjusted for clinical, behavioral, and demographic characteristics.

RESULTS

Those with longer EW tended to have less SB and greater energy intake, suggesting that some individuals may balance greater intake with greater expenditure. After adjustments including energy balance, each hour of EW was associated with 0.29% higher BMI (95% confidence interval [CI]: 0.07, 0.51; P = 0.011). Longer EW and caloric EW (EWC, EW, caloric meals only) were associated with several obesity-associated GMB taxa, such as Streptococcus (enriched, β: 0.04; 95% CI: 0.01, 0.07, for EW). MOI was not significantly associated with adiposity or GMB characteristics.

CONCLUSIONS

Shorter EW may promote healthy weight, but some individuals with longer compared with shorter EWs tend to have greater activity that could balance their greater energy intake. EW and EWC may influence GMB characteristics.

Clustering unhealthy lifestyle factors in Chinese children and adolescents with overweight or obesity

BACKGROUND

This study used latent class analysis (LCA) to examine the potential patterns of unhealthy lifestyle factors (ULFs) and their association with overweight and obesity in children and adolescents with overweight or obesity in China.

METHODS

We conducted three cross-sectional surveys, recruiting 7,927 children with obesity or overweight from September 2019 to January 2022. We used LCA to identify patterns of co-occurrence of ULFs based on seven types of behaviors. Multinomial logistic regression model was constructed to examine the association of fetal and neonatal factors with the clusters of ULFs.

RESULTS

Of 7,927 participants, 7,627 (96.78%) had at least one ULF, and 6,942 (87.57%) had two or more ULFs concurrently. Using LCA, four distinct clusters were identified based on the elbow point of the Akaike's information criterion (AIC), that is, "unhealthy food intake but long sleeping", "relative health", "healthy food intake but unhealthy eating-sleeping-sitting habits", and "unhealthy food intake and unhealthy sitting-activity habits". Moreover, several factors including sex, age, infancy feeding, parental obesity, and parental age were significantly associated with the clusters of ULFs.

CONCLUSIONS

We provide evidence on how multiple ULFs in combination may influence health among Chinese children and adolescents with overweight or obesity, and we agree that further external validations are warranted.

CLINICAL TRIAL NUMBER

Not applicable.

What Factors Influence Obesity in Spain? A Multivariate Analysis of Sociodemographic, Nutritional, and Lifestyle Factors Affecting Body Mass Index in the Spanish Population

AIM

This cross-sectional study examines sociodemographic, nutritional, and lifestyle factors affecting Body Mass Index (BMI) in the Spanish population, with a particular emphasis on obesity.

METHODS

A sample of 22,181 Spanish residents aged 18 years and older was recruited through digital and physical channels from August 2020 to November 2021. Data were collected using the validated NutSo-HH questionnaire, which includes sections on sociodemographic information, health perceptions, eating habits, and lifestyle factors.

RESULTS

Among respondents, 661 (3%) were underweight (BMI < 18.5 kg/m2), 14,562 (65.7%) were normal weight (18.5 kg/m2 ≤ BMI ≤ 25 kg/m2), 4825 respondents (21.8%) were overweight (25 kg/m2 < BMI ≤ 30 kg/m2), and 2133 (9.6%) were obese (BMI > 30 kg/m2), with significant differences across these groups in relation to diet and lifestyle behaviors. Principal Component Analysis (PCA) was employed to identify the primary variables influencing obesity, revealing that poor dietary habits (frequent consumption of fast food, fried foods, and ultra-processed items) were negatively correlated with healthy behaviors such as regular fish consumption and physical activity. The PCA plot indicated notable distinctions based on educational attainment and age, with individuals with lower educational levels displaying poorer nutritional patterns and younger participants exhibiting higher fast food consumption and poorer sleep quality. Statistical analyses confirmed that sociodemographic factors, including age, education, and income level, significantly influenced BMI. Some differences were also found according to the place of residence.

CONCLUSIONS

These findings underscore the need for targeted interventions that address both sociodemographic and lifestyle factors to mitigate obesity risk in Spain.

Time Restricted Eating: A Valuable Alternative to Calorie Restriction for Addressing Obesity?

PURPOSE OF REVIEW

In this review, we summarize the molecular effects of time-restricted eating (TRE) and its possible role in appetite regulation. We also discuss the potential clinical benefits of TRE in obesity.

RECENT FINDINGS

TRE is an emerging dietary approach consisting in limiting food intake to a specific window of time each day. The rationale behind this strategy is to restore the circadian misalignment, commonly seen in obesity. Preclinical studies have shown that restricting food intake only during the active phase of the day can positively influence several cellular functions including senescence, mitochondrial activity, inflammation, autophagy and nutrients' sensing pathways. Furthermore, TRE may play a role by modulating appetite and satiety hormones, though further research is needed to clarify its exact mechanisms. Clinical trials involving patients with obesity or type 2 diabetes suggest that TRE can be effective for weight loss, but its broader effects on improving other clinical outcomes, such as cardiovascular risk factors, remain less certain. The epidemic proportions of obesity cause urgency to find dietary, pharmacological and surgical interventions that can be effective in the medium and long term. According to its molecular effects, TRE can be an interesting alternative to caloric restriction in the treatment of obesity, but the considerable variability across clinical trials regarding population, intervention, and follow-up duration makes it difficult to reach definitive conclusions.

Interrelation Between BMI, Dietary Habits, Self-Rated Health, and Body Image Perception Among Korean Adolescents: The Korea Youth Risk Behavior Web-Based Survey (2022)

BACKGROUND/OBJECTIVES

Adolescent obesity is highly likely to lead to adult obesity and is associated with dietary habits, subjective health, and body image perception. This study aimed to analyze the relationships between BMI, dietary habits, subjective health perception, and body image perception among Korean adolescents using data from the 18th Korea Youth Risk Behavior Survey conducted in 2022 to explore strategies for reducing adolescent obesity rates.

METHODS

Data from 50,427 participants were analyzed, including BMI, seven lifestyle factors (intake frequencies of water, milk, fruit, soft drinks, vegetables, breakfast, and late-night snacks), and responses to one item each for subjective health perception and body image perception.

RESULTS

Higher intake frequencies of breakfast, fruits, soft drinks, and late-night snacks were associated with lower BMI (p < 0.001). However, among high school students, those with lower water and breakfast intake but higher soft drink and late-night snack intake exhibited an increasing trend in BMI. Subjective health perception and body image perception were interrelated, with subjective health perception influencing body image perception (p < 0.001).

CONCLUSIONS

Addressing nutritional issues within schools, including improving school meals, regulating accessible products, and providing nutritional intake guidelines, is essential. Additionally, developing tailored health education programs to promote healthy body image perceptions is necessary. This study can serve as a foundational resource for analyzing adolescent health and developing strategies to improve health behaviors in changing environments.

Chrononutrition patterns and their association with body weight: Differences across multiple chronotypes

INTRODUCTION

In recent years, the focus of research on obesity and its management has expanded beyond traditional dietary factors to include the timing of food intake - in relation to the body's circadian rhythms - known as chrononutrition. However, chrononutrition patterns remain largely unexplored in low-medium income countries. Our study aimed to investigate the association between chrononutrition patterns and BMI.

MATERIAL AND METHODS

Utilizing data from the virtual Survey SONAR-Brazil (n=2137,18-65 y), we defined the following chrononutrition patterns: 1. The clock time of the first, mid, and last eating events; 2. Morning and evening latencies (from wake-up time until the first eating event, and from the last eating event until bedtime); and 3. Eating window. Linear regression analyses assessed associations between chrononutrition variables and BMI. Quantile regression and restricted cubic splines were used to explore distributional correlations and association shapes.

RESULTS

Among all participants, BMI increased with each additional hour of the first eating event (β=0.17; 95% CI, 0.05,0.29; P=0.005), morning latency (β=0.27; 95% CI, 0.12,0.42; P<0.001), and eating midpoint (β=0.21; 95% CI, 0.05,0.38; P=0.01) and the effect was even stronger with higher BMI percentiles. There was no effect of eating times among intermediate and late chronotypes. However, among early types, positive associations were seen between the BMI and the timing of the first eating event, morning latency, and eating midpoint, as well as a negative association with evening eating.

CONCLUSIONS

Our findings suggest that delaying the first eating event, the eating midpoint, and extending morning latency are associated with higher BMI, particularly in early chronotypes. These results highlight the importance of aligning eating patterns with chronotypes and support personalized dietary recommendations.

Influence of lifestyle and the circadian clock on reproduction

Background

The biological reproductive process requires the precise coordination of annual and daily signals to adapt to environmental shifts. Humans and animals have developed shared neuroendocrine systems that have adapted to process daily and seasonal light signals within the hypothalamic-pituitary -gonadal axis. However, the stability of circadian and seasonal biological processes is at risk due to industrialization and contemporary round-the-clock lifestyles. These threats include skipping breakfast, excessive artificial illumination during inappropriate hours because of irregular work schedules, nighttime urban lighting, and widespread environmental pollution from endocrine-disrupting chemicals. This review aimed to explore the interplay between lifestyle factors, circadian rhythms, and reproductive functions.

Methods

This review examined the reciprocal influences of circadian clocks on reproductive hormones, exploring the underlying mechanisms and their implications for fertility and reproductive health. We emphasized key findings regarding molecular clock components, endocrine pathways, and the critical importance of synchronizing circadian rhythms with hormonal cycles.

Main Findings

The intersection of reproductive endocrinology and circadian biology reveals complex interactions between hormonal regulation and circadian rhythms. Circadian rhythm misalignments due to environmental factors, including late-night work and skipping breakfast, negatively impact endocrine and reproductive functions.

Conclusions

More strategies are needed to mitigate the effects of circadian disruption on reproductive functions.

Comparison of the Effects of Inappropriate Meal Timing-Induced and Genetic Models of Circadian Clock Disruption on Uterine mRNA Expression Profiles

BACKGROUND

Accumulating evidence reveals that inappropriate meal timing contributes to the development of lifestyle-related diseases. An underlying mechanism is thought to be the disruption of the intracellular circadian clock in various tissues based on observations in both systemic and tissue-specific clock gene-deficient mice. However, whether the effects of conditional clock gene knockout are comparable to those of inappropriate meal timing remains unclear.

OBJECTIVES

This study aimed to compare the effects of a recently developed 28-h feeding cycle model with those of a core clock gene Bmal1 uterine conditional knockout (Bmal1 cKO) model on uterine mRNA expression profiles.

METHODS

The models were generated by subjecting C57BL/6J mice to an 8-h/20-h feeding/fasting cycle for 2 wk and crossing Bmal1-floxed mice with PR-Cre mice. Microarray analyses were conducted using uterine samples obtained at the beginning of the dark and light periods.

RESULTS

The analyses identified 516 and 346, significantly 4-fold and 2-fold, up- or downregulated genes in the 28-h feeding cycle and Bmal1 cKO groups, respectively, compared with each control group. Among these genes, only 7 (1.4%) and 63 (18.2%) were significantly up- or downregulated in the other model. Moreover, most (n = 44, 62.9%) of these genes were oppositely regulated. These findings were confirmed by gene set enrichment analyses.

CONCLUSIONS

This study reveals that a 28-h feeding cycle and Bmal1 cKO differently affect gene expression profiles and highlights the need for considering this difference to assess the pathophysiology of diseases associated with inappropriate meal timing.

Association of late eating with colorectal adenomas: a cross-sectional study

PURPOSE

Colorectal cancer (CRC) is linked to lifestyle exposures. However, changes in the CRC rates among younger populations remain poorly understood and suggest the existence of yet unidentified factor(s) that may contribute to colon carcinogenesis. Here, we investigated the potential role of time of eating in the risk of pre-cancerous colonic neoplasms (tubular adenoma: TA).

METHODS

We enrolled 663 participants undergoing screening colonoscopies. Data on food timing, dietary intake, sleep/wake patterns, and chronotype were collected through structured questionnaires. Late eating was defined as the consumption of food or snack within a 3-hour window of sleep onset for at least four days a week. Pathology reports confirmed the histology of colonic polyps, and adenomas were further classified into risk categories.

RESULTS

A total of 644 patients met criteria for our study. There were 270 (42.2%) participants classified as late eaters. Compared to non-late eaters, the odds of TA were higher in late eaters (OR = 1.46, 95% CI = 1.05-2.03, p = 0.023), an association which was strengthened after adjusting for multiple confounders (OR 1.98, 95% CI 1.19-3.28, p = 0.008). Late eating remained an independent risk factor for high-risk as well as multiple TAs.

CONCLUSION

This study proposes late eating as a risk factor for colon tubular adenomas and underscores the potential role of less studied forms of circadian disruption imposed by time of eating in the development of colon neoplastic formation.

Meal Timing and Anthropometric and Metabolic Outcomes: A Systematic Review and Meta-Analysis

Importance

Meal timing strategies, such as time-restricted eating (TRE), reducing meal frequency, or altering calorie distribution across the day, have gained interest for their potential to enhance weight loss and metabolic health, particularly in managing chronic diseases, yet their long-term benefits are not known.

Objective

To evaluate the association between meal timing strategies (≥12 weeks) and anthropometric and metabolic indicators.

Data Sources

Medline, Embase, CINAHL, and Cochrane CENTRAL were searched from inception to October 17, 2023.

Study Selection

Randomized clinical trials, regardless of language and publication date, involving adults 18 years and older, evaluating within-day meal timing patterns for 12 or more weeks, and reporting anthropometric measures were included. Studies were excluded if participants had eating disorders, prior significant weight change, underwent bariatric surgery, were pregnant, or if controlled variables differed between groups.

Data Extraction and Synthesis

Study quality was determined via Risk of Bias 2.0 tool. Data were extracted independently by multiple reviewers. Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were used. Meta-analysis was performed using random-effects model on pooled continuous outcomes with 2 or more studies.

Main Outcome and Measures

Weight change in kilograms, reported as between-group mean difference with 95% CIs.

Results

Sixty-nine reports of 29 randomized clinical trials including 2485 individuals (1703 [69%] female; mean [SD] age, 44 [9.5] years; and mean [SD] body mass index, 33 [3.5]) were included. Study interventions included TRE (17 studies), meal frequency (8 studies), and calorie distribution (4 studies). There were some concerns of risk of bias for 7 studies and high concerns for 22 studies. Statistically significant weight change was observed in TRE when compared with control (-1.37 kg; 95% CI, -1.99 to -0.75 kg). Lower meal frequency and earlier caloric distribution were also both associated with greater change (-1.85 kg; 95% CI, -3.55 to -0.13 kg; and -1.75 kg; 95% CI, -2.37 to -1.13 kg, respectively).

Conclusions and Relevance

The findings of this meta-analysis suggest that TRE, lower meal frequency, and earlier caloric distribution in the day may reduce weight compared with standard care and/or nutritional advice; however, the effect sizes found were small and of uncertain clinical importance. High heterogeneity and risk of bias among included studies led to concerns about the certainty of the underpinning evidence. Further research, including trials with larger sample sizes, standardized interventions with prescribed or matched energy intake, and longer follow-up, are needed.

Gender differences in body composition, dietary patterns, and physical activity: insights from a cross-sectional study

Introduction

This study investigates the interplay between body composition, dietary patterns, and physical activity across genders, focusing on gender-specific differences in food preferences and eating behaviors. Understanding these interactions is crucial for developing targeted nutritional and lifestyle interventions.

Methods

A cross-sectional study was conducted with 1,333 participants (58.7% female, 41.3% male), aged 18-65 years. Participants were categorized into tertiles based on their fat mass to fat-free mass (FM-to-FFM) ratio. Data on dietary choices, eating behaviors, and physical activity were collected and analyzed to identify gender-specific trends.

Results

Significant gender-specific differences were observed in food preferences and eating behaviors. Males experienced greater hunger in the late afternoon, while females felt more hunger in the morning. Males showed a preference for processed and red meats, whereas females preferred cooked vegetables. Eating behaviors such as meal skipping, uncontrolled eating, nocturnal eating, and taste preferences (sweet or salty) varied distinctly between FM-to-FFM tertiles and genders. Higher FM-to-FFM ratios correlated with lower physical activity levels, particularly in strength training and general sports engagement.

Discussion

These findings highlight the complex interactions between body composition, dietary habits, and lifestyle factors, emphasizing gender-specific differences. The results suggest that body composition and BMI significantly impact health-related behaviors, necessitating tailored interventions to address these differences and promote healthier lifestyles.

Effects of (Poly)phenols on Circadian Clock Gene-Mediated Metabolic Homeostasis in Cultured Mammalian Cells: A Scoping Review

Circadian clocks regulate metabolic homeostasis. Disruption to our circadian clocks, by lifestyle behaviors such as timing of eating and sleeping, has been linked to increased rates of metabolic disorders. There is now considerable evidence that selected dietary (poly)phenols, including flavonoids, phenolic acids and tannins, may modulate metabolic and circadian processes. This review evaluates the effects of (poly)phenols on circadian clock genes and linked metabolic homeostasis in vitro, and potential mechanisms of action, by critically evaluating the literature on mammalian cells. A systematic search was conducted to ensure full coverage of the literature and identified 43 relevant studies addressing the effects of (poly)phenols on cellular circadian processes. Nobiletin and tangeretin, found in citrus, (-)-epigallocatechin-3-gallate from green tea, urolithin A, a gut microbial metabolite from ellagitannins in fruit, curcumin, bavachalcone, cinnamic acid, and resveratrol at low micromolar concentrations all affect circadian molecular processes in multiple types of synchronized cells. Nobiletin emerges as a putative retinoic acid-related orphan receptor (RORα/γ) agonist, leading to induction of the circadian regulator brain and muscle ARNT-like 1 (BMAL1), and increased period circadian regulator 2 (PER2) amplitude and period. These effects are clear despite substantial variations in the protocols employed, and this review suggests a methodological framework to help future study design in this emerging area of research.

Transfer with microbiota from lean donors prevents excessive weight gain and restores gut-brain vagal signaling in obese rats maintained on a high fat diet

Background

The collection of microorganisms, mainly bacteria, which live in the gastrointestinal (GI) tract are collectible known as the gut microbiota. GI bacteria play an active role in regulation of the host's immune system and metabolism, as well as certain pathophysiological processes. Diet is the main factor modulating GI microbiota composition and recent studies have shown that high fat (HF) diets induce detrimental changes, known as dysbiosis, in the GI bacterial makeup. HF diet induced microbiota dysbiosis has been associated with structural and functional changes in gut-brain vagally mediated signaling system, associated with overeating and obesity. Although HF-driven changes in microbiota composition are sufficient to alter vagal signaling, it is unknown if restoring normal microbiota in obesity can improve gut-brain signaling and metabolic outcomes. In this study, we evaluated the effect of lean gut microbiota transfer in obese, vagally compromised, rats on gut-brain communication, food intake, and body weight. Male Sprague-Dawley rats were maintained on regular chow, or 45% HF diet for nine weeks followed by three weeks of microbiota depletion using an antibiotic cocktail. The animals were then divided into four groups (n=10 each): LF - control group on regular chow, LF-LF - chow fed animals that received antibiotics and microbiota from chow fed animals, HF-LF - HF fed animals that received microbiota from chow fed animals, and HF-HF - HF fed animals that received microbiota from HF fed animals. Animals were gavaged with donor microbiota for three consecutive days on week one and once a week thereafter for three more weeks. HF-LF animals received inulin as a prebiotic to aid the establishment of the lean microbiome.

Results

We found that transferring a LF microbiota to HF fed animals (HF-LF) reduced caloric intake during the light phase when compared with HF-HF rats and prevented additional excessive weight gain. We did not observe significant changes in the density of vagal afferents terminating in the brainstem among the groups, however, HF-LF animals displayed an increase in postprandial activation of both primary sensory neurons innervating the GI tract and brainstem secondary neurons.

Conclusions

We concluded from these data that normalizing microbiota composition in obese rats improves gut-brain communication and restores normal feeding patterns which was associated with a reduction in weight gain.

A Narrative Review of the Significance of Popular Diets in Diabetes Mellitus Management

Diabetes mellitus is a collection of metabolic disorders marked by elevated levels of glucose in the blood due to irregularities in the generation or functioning of insulin. Medical nutrition therapy and weight loss are crucial elements in the management of diabetes and the prevention of complications. Several diets have become popular over time for the goal of achieving weight loss, but their popularity has declined due to a lack of reliable scientific evidence. This study classifies popular diets into three categories: diets that manage the composition of macronutrients, diets that restrict specific foods or food groups, and diets that manipulate meal timing. The review includes research studies that investigated the effects of popular diets on the prevention, management, and complications of diabetes. It is clear that different popular diets can have positive effects on both preventing and treating diabetes and preventing and treating complications related to diabetes. However, it is not practical to determine which diet is the most effective option for preventing or controlling diabetes. Thus, the main focus should be on common underlying factors that support well-being, such as decreasing the intake of refined grains and added sugar, choosing non-starchy vegetables, and giving priority to whole foods over processed foods whenever possible, until there is stronger evidence supporting the specific benefits of different dietary patterns.

Eating Habits and Lifestyle Factors Related to Childhood Obesity Among Children Aged 5-6 Years: Cluster Analysis of Panel Survey Data in Korea

BACKGROUND

Childhood obesity has emerged as a major health issue due to the rapid growth in the prevalence of obesity among young children worldwide. Establishing healthy eating habits and lifestyles in early childhood may help children gain appropriate weight and further improve their health outcomes later in life.

OBJECTIVE

This study aims to classify clusters of young children according to their eating habits and identify the features of each cluster as they relate to childhood obesity.

METHODS

A total of 1280 children were selected from the Panel Study on Korean Children. Data on their eating habits (eating speed, mealtime regularity, consistency of food amount, and balanced eating), sleep hours per day, outdoor activity hours per day, and BMI were obtained. We performed a cluster analysis on the children's eating habits using k-means methods. We conducted ANOVA and chi-square analyses to identify differences in the children's BMI, sleep hours, physical activity, and the characteristics of their parents and family by cluster.

RESULTS

At both ages (ages 5 and 6 years), we identified 4 clusters based on the children's eating habits. Cluster 1 was characterized by a fast eating speed (fast eaters); cluster 2 by a slow eating speed (slow eaters); cluster 3 by irregular eating habits (poor eaters); and cluster 4 by a balanced diet, regular mealtimes, and consistent food amounts (healthy eaters). Slow eaters tended to have the lowest BMI (P<.001), and a low proportion had overweight and obesity at the age of 5 years (P=.03) and 1 year later (P=.005). There was a significant difference in sleep time (P=.01) and mother's education level (P=.03) at the age of 5 years. Moreover, there was a significant difference in sleep time (P=.03) and the father's education level (P=.02) at the age of 6 years.

CONCLUSIONS

Efforts to establish healthy eating habits in early childhood may contribute to the prevention of obesity in children. Specifically, providing dietary guidance on a child's eating speed can help prevent childhood obesity. This research suggests that lifestyle modification could be a viable target to decrease the risk of childhood obesity and promote the development of healthy children. Additionally, we propose that future studies examine long-term changes in obesity resulting from lifestyle modifications in children from families with low educational levels.

Association of the timing of evening eating with BMI Z-score and waist-to-height ratio among preschool-aged children in Finland

Later timing of eating has been associated with higher adiposity among adults and children in several studies, but not all. Moreover, studies in younger children are scarce. Hence, this study investigated the associations of the timing of evening eating with BMI Z-score and waist-to-height ratio (WHtR), and whether these associations were moderated by chronotype among 627 preschoolers (3-6-year-olds) from the cross-sectional DAGIS survey in Finland. Food intake was measured with 3-d food records, and sleep was measured with hip-worn actigraphy. Three variables were formed to describe the timing of evening eating: (1) clock time of the last eating occasion (EO); (2) time between the last EO and sleep onset; and (3) percentage of total daily energy intake (%TDEI) consumed 2 h before sleep onset or later. Chronotype was assessed as a sleep debt-corrected midpoint of sleep on the weekend (actigraphy data). The data were analysed with adjusted linear mixed effects models. After adjusting for several confounders, the last EO occurring closer to sleep onset (estimate = -0·006, 95 % CI (-0·010, -0·001)) and higher %TDEI consumed before sleep onset (estimate = 0·0004, 95 % CI (0·00003, 0·0007)) were associated with higher WHtR. No associations with BMI Z-score were found after adjustments. Clock time of the last EO was not significantly associated with the outcomes, and no interactions with chronotype emerged. The results highlight the importance of studying the timing of eating relative to sleep timing instead of only as clock time.

Dietary trends and obesity in Saudi Arabia

Introduction

Dietary habits in Saudi Arabia have been shifting toward the Western diet, which is high in fat, salt, and sugar, leading to a high obesity rate. Different dietary strategies such as the Ketogenic Diet (KD), Intermittent Fasting (IF), Gluten Free Diet (GFD), and Calorie Restriction Diet (CRD) have shown an influential role in weight loss. This study aimed to compare trending diets and correlate different types of diet with obesity and lifestyle among adults in Saudi Arabia.

Methods

A cross-sectional study was performed on Saudis and non-Saudis over 18 years old. We used convenience sampling, an online questionnaire distributed via social media channels, including WhatsApp, LinkedIn, and Twitter. SPSS 28 software was applied for data analysis. The chi-square test was used to determine associations between different variables. Statistical significance was considered at a value of p less than 0.05.

Results

Most participants were females residing in the Eastern and Central regions of Saudi Arabia. Although most do not follow any dietary plan, they exhibited acceptable exercise and lifestyle. The minority of the study population followed different types of diet plans, such as KD, IF, and GFD. The purpose of most of the participants who have used these strategies was for weight loss but failed to sustain the dietary plan for more than 1 month.

Conclusion

Obesity remains a challenging issue in Saudi Arabia. Adherence to dietary regimes could help in controlling obesity. Increasing the awareness of the benefits of each dietary plan for health, choosing the appropriate one, and sustaining a balanced nutrition pattern.

Lifestyle, meal times, and sleep patterns changes in higher education professors during COVID-19: Association with non-communicable chronic diseases

BACKGROUND

In response to the COVID-19 pandemic, educational institutions had to swiftly adapt and transition to remote teaching in order to maintain academic activities. However, these changes presented a number of challenges for professors, which could have negative effects on their health.

OBJECTIVE

To analyze the association between changes in dietary and sleep habits, physical activity level, and sedentary behavior with the development of non-communicable diseases (NCDs) among Brazilian higher education professors during the pandemic period.

METHODS

This is a cross-sectional and retrospective study conducted using an online form. Generalized linear models, adjusted for age, sex, and body mass index, were used to verify the difference between pre-pandemic and pandemic periods. Logistic regression models were used to predict the odds ratio (OR) for the development of NCDs according to physical activity time, sedentary behavior time, dietary and sleep patterns.

RESULTS

A total of 936 professors residing across Brazil participated in the survey. The duration of sedentary behavior increased, sleep duration slightly decreased, and meal times shifted to earlier during the pandemic. A total of 22.9%of the participants reported the diagnosis of some NCDs during this period. Physical activity practice was associated with a lower risk of diseases during the pandemic, regardless of the intensity performed. On the other hand, late eating habits and excessive food consumption during the pandemic were associated with a higher risk.

CONCLUSION

The results provide data that can help in the development of public policies that promote health actions to minimize the consequences associated with the pandemic period.

Transfer of microbiota from lean donors in combination with prebiotics prevents excessive weight gain and improves gut-brain vagal signaling in obese rats

Gastrointestinal (GI) microbiota plays an active role in regulating the host's immune system and metabolism, as well as certain pathophysiological processes. Diet is the main factor modulating GI microbiota composition and studies have shown that high fat (HF) diets induce detrimental changes (dysbiosis) in the GI bacterial makeup. HF diet induced dysbiosis has been associated with structural and functional changes in gut-brain vagally mediated signaling system, associated with overeating and obesity. Although HF-driven changes in microbiota composition are sufficient to alter vagal signaling, it is unknown if improving microbiota composition after diet-induced obesity has been established can ameliorate gut-brain signaling and metabolic outcomes. In this study, we evaluated the effect of lean gut microbiota transfer in obese, vagally compromised, rats on gut-brain communication, food intake, and body weight. Male rats were maintained on regular chow or 45% HF diet for nine weeks followed by three weeks of microbiota depletion using antibiotics. The animals were then divided into four groups (n = 10 each): LF - control fed regular chow, LF-LF - chow fed animals that received microbiota from chow fed donors, HF-LF - HF fed animals that received microbiota from chow fed donors, and HF-HF - HF fed animals that received microbiota from HF fed donors. HF-LF animals received inulin as a prebiotic to aid the establishment of the lean microbiome. We found that transferring a LF microbiota to HF fed animals (HF-LF) reduced caloric intake during the light phase when compared with HF-HF rats and prevented additional excessive weight gain. HF-LF animals displayed an increase in postprandial activation of both primary sensory neurons innervating the GI tract and brainstem secondary neurons. We concluded from these data that improving microbiota composition in obese rats is sufficient to ameliorate gut-brain communication and restore normal feeding patterns which was associated with a reduction in weight gain.

Lifestyle management of hypertension: International Society of Hypertension position paper endorsed by the World Hypertension League and European Society of Hypertension

Hypertension, defined as persistently elevated systolic blood pressure (SBP) >140 mmHg and/or diastolic blood pressure (DBP) at least 90 mmHg (International Society of Hypertension guidelines), affects over 1.5 billion people worldwide. Hypertension is associated with increased risk of cardiovascular disease (CVD) events (e.g. coronary heart disease, heart failure and stroke) and death. An international panel of experts convened by the International Society of Hypertension College of Experts compiled lifestyle management recommendations as first-line strategy to prevent and control hypertension in adulthood. We also recommend that lifestyle changes be continued even when blood pressure-lowering medications are prescribed. Specific recommendations based on literature evidence are summarized with advice to start these measures early in life, including maintaining a healthy body weight, increased levels of different types of physical activity, healthy eating and drinking, avoidance and cessation of smoking and alcohol use, management of stress and sleep levels. We also discuss the relevance of specific approaches including consumption of sodium, potassium, sugar, fibre, coffee, tea, intermittent fasting as well as integrated strategies to implement these recommendations using, for example, behaviour change-related technologies and digital tools.

Temporal patterns of energy intake identified by the latent class analysis in relation to prevalence of overweight and obesity in Iranian adults

We aimed to identify temporal patterns of energy intake and investigate their association with adiposity. We performed a cross-sectional study of 775 adults in Iran. Information about eating occasions across the day was collected by three 24-h dietary recalls. Latent class analysis (LCA) was used to identify temporal eating patterns based on whether or not an eating occasion occurred within each hour of the day. We applied binary logistic regression to estimate the OR and 95 % CI of overweight and obesity (defined as BMI of 25-29·9 and ≥ 30 kg/m2, respectively) across temporal eating patterns while controlling for potential confounders. LCA grouped participants into three exclusive sub-groups named 'Conventional', 'Earlier breakfast' and 'Later lunch'. The 'Conventional' class was characterised by high probability of eating occasions at conventional meal times. 'Earlier breakfast' class was characterised by high probability of a breakfast eating occasion 1 h before the conventional pattern and a dinner eating occasion 1 h after the conventional pattern, and the 'Later lunch' class was characterised by a high probability of a lunch eating occasion 1 h after the conventional pattern. Participants in the 'Earlier breakfast' pattern had a lower likelihood of obesity (adjusted OR: 0·56, 95 % CI: 0·35, 0·95) as compared with the 'Conventional' pattern. There was no difference in the prevalence of obesity or overweight between participants in the 'Later lunch' and the 'Conventional' patterns. We found an inverse association between earlier eating pattern and the likelihood of obesity, but reverse causation may be a plausible explanation.

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.

Sweet treats before sleep disrupt the clock system and increase metabolic risk markers in healthy rats

AIM

Biological rhythms are endogenously generated natural cycles that act as pacemakers of different physiological mechanisms and homeostasis in the organism, and whose disruption increases metabolic risk. The circadian rhythm is not only reset by light but it is also regulated by behavioral cues such as timing of food intake. This study investigates whether the chronic consumption of a sweet treat before sleeping can disrupt diurnal rhythmicity and metabolism in healthy rats.

METHODS

For this, 32 Fischer rats were administered daily a low dose of sugar (160 mg/kg, equivalent to 2.5 g in humans) as a sweet treat at 8:00 a.m. or 8:00 p.m. (ZT0 and ZT12, respectively) for 4 weeks. To elucidate diurnal rhythmicity of clock gene expression and metabolic parameters, animals were sacrificed at different times, including 1, 7, 13, and 19 h after the last sugar dose (ZT1, ZT7, ZT13, and ZT19).

RESULTS

Increased body weight gain and higher cardiometabolic risk were observed when sweet treat was administered at the beginning of the resting period. Moreover, central clock and food intake signaling genes varied depending on snack time. Specifically, the hypothalamic expression of Nampt, Bmal1, Rev-erbα, and Cart showed prominent changes in their diurnal expression pattern, highlighting that sweet treat before bedtime disrupts hypothalamic control of energy homeostasis.

CONCLUSIONS

These results show that central clock genes and metabolic effects following a low dose of sugar are strongly time-dependent, causing higher circadian metabolic disruption when it is consumed at the beginning of the resting period, that is, with the late-night snack.

Type 2 Diabetes Mellitus and Sarcopenia as Comorbid Chronic Diseases in Older Adults: Established and Emerging Treatments and Therapies

Type 2 diabetes mellitus (T2DM) and sarcopenia (low skeletal muscle mass and function) share a bidirectional relationship. The prevalence of these diseases increases with age and they share common risk factors. Skeletal muscle fat infiltration, commonly referred to as myosteatosis, may be a major contributor to both T2DM and sarcopenia in older adults via independent effects on insulin resistance and muscle health. Many strategies to manage T2DM result in energy restriction and subsequent weight loss, and this can lead to significant declines in muscle mass in the absence of resistance exercise, which is also a first-line treatment for sarcopenia. In this review, we highlight recent evidence on established treatments and emerging therapies targeting weight loss and muscle mass and function improvements in older adults with, or at risk of, T2DM and/or sarcopenia. This includes dietary, physical activity and exercise interventions, new generation incretin-based agonists and myostatin-based antagonists, and endoscopic bariatric therapies. We also highlight how digital health technologies and health literacy interventions can increase uptake of, and adherence to, established and emerging treatments and therapies in older adults with T2DM and/or sarcopenia.

Evaluation of the "Shifting Weight using Intermittent Fasting in night-shift workers" weight loss interventions: a mixed-methods protocol

Introduction

Shift workers are at a greater risk for obesity-related conditions. The impacts of working at night presents a challenge for designing effective dietary weight-loss interventions for this population group. The Shifting Weight using Intermittent Fasting in night-shift workers (SWIFt) study is a world-first, randomized controlled trial that compares three weight-loss interventions. While the trial will evaluate the effectiveness of weight-loss outcomes, this mixed-methods evaluation aims to explore for who weight-loss outcomes are achieved and what factors (intervention features, individual, social, organisational and wider environmental) contribute to this.

Methods

A convergent, mixed-methods evaluation design was chosen where quantitative and qualitative data collection occurs concurrently, analyzed separately, and converged in a final synthesis. Quantitative measures include participant engagement assessed via: dietary consult attendance, fulfillment of dietary goals, dietary energy intake, adherence to self-monitoring, and rates for participant drop-out; analyzed for frequency and proportions. Regression models will determine associations between engagement measures, participant characteristics (sex, age, ethnicity, occupation, shift type, night-shifts per week, years in night shift), intervention group, and weight change. Qualitative measures include semi-structured interviews with participants at baseline, 24-weeks, and 18-months, and fortnightly audio-diaries during the 24-week intervention. Interviews/diaries will be transcribed verbatim and analyzed using five-step thematic framework analysis in NVivo. Results from the quantitative and qualitative data will be integrated via table and narrative form to interrogate the validity of conclusions.

Discussion

The SWIFt study is a world-first trial that compares the effectiveness of three weight-loss interventions for night shift workers. This mixed-methods evaluation aims to further explore the effectiveness of the interventions. The evaluation will determine for who the SWIFt interventions work best for, what intervention features are important, and what external factors need to be addressed to strengthen an approach. The findings will be useful for tailoring future scalability of dietary weight-loss interventions for night-shift workers.Clinical trial registration: This evaluation is based on the SWIFt trial registered with the Australian New Zealand Clinical Trials Registry [ACTRN 12619001035112].

Intermittent fasting for the prevention of cardiovascular disease: implications for clinical practice

Cardiovascular disease remains one of the most prevalent and preventable chronic conditions worldwide. Nutrition plays an important role in reducing several risk factors associated with cardiovascular disease. Intermittent fasting has been rapidly gaining interest among patients with cardiometabolic disease as a nutritional strategy for improving cardiovascular outcomes. However, research had yet to determine whether intermittent fasting provides greater cardiometabolic benefits compared to continuous daily caloric restriction. A recent Cochrane review has synthesised the benefits of intermittent fasting for the prevention of cardiovascular disease but is limited by its interpretation of the findings for clinical practice. This commentary aims to critically appraise the methods used within the review by Allaf et al, 2021 and expand upon the findings to determine its implications for clinical practice.

Breakfast Skipping is associated with More Deleterious Lifestyle Behaviors among Japanese Men: The TRF-Japan Study Using the Original "Taberhythm" Smartphone Application

Background

Time-restricted eating has been increasingly recognized as a promising option to reduce food intake and combat obesity. Especially in Asian countries such as Japan, because of the wide variety of food choices available, a dietary approach that emphasizes meal timing can be more practical and easier to implement and adhere to, compared with approaches that focus on specific dietary content, such as low-fat or low-carbohydrate diets.

Objectives

We aimed to identify eating patterns among Japanese men and women using a smartphone application (app) called "Taberhythm." In addition, we sought to evaluate the relationship of breakfast eating habits with lifestyle behaviors and body mass index, and determine whether sex differences were present.

Methods

A total of 3369 smartphone users were eligible to participate in this observational study. Users recorded 1 mo of lifestyle logs using the app; 254 participants (178 women, 38 ± 12 y old, body mass index 23.3 ± 4.9 kg/m2) had sufficient records to calculate daily fasting duration and sleep duration, and were eligible for the analyses.

Results

Fasting duration was ∼12.6 h and was longer in women than men, among participants who never skipped breakfast. Breakfast skipping was associated with longer screen time, and more frequent snacking, only in men. Men with irregular breakfast eating patterns had a longer duration of fasting after awakening that was associated with obesity.

Conclusions

We investigated eating patterns among Japanese people using a smartphone app and revealed that skipping breakfast was more deleterious in men than in women.

Healthy Eating for Elective Major Orthopedic Surgery: Quality, Quantity, and Timing

Improvements to enhanced recovery pathways in orthopedic surgery are reducing the time that patients spend in the hospital, giving an increasingly vital role to prehabilitation and/or rehabilitation after surgery. Nutritional support is an important tenant of perioperative medicine, with the aim to integrate the patient's diet with food components that are needed in greater amounts to support surgical fitness. Regardless of the time available between the time of contemplation of surgery and the day of admission, a patient who eats healthy is reasonably more suitable for surgery than a patient who does not meet the daily requirements for energy and nutrients. Moreover, a successful education for healthy food choices is one possible way to sustain the exercise therapy, improve recovery, and thus contribute to the patient's long-term health. The expected benefits presuppose that the patient follows a healthy diet, but it is unclear which advice is needed to improve dietary choices. We present the principles of healthy eating for patients undergoing major orthopedic surgery to lay the foundations of rational and valuable perioperative nutritional support programs. We discuss the concepts of nutritional use of food, requirements, portion size, dietary target, food variety, time variables of feeding, and the practical indications on what the last meal to be consumed six hours before the induction of anesthesia may be together with what is meant by clear fluids to be consumed until two hours before. Surgery may act as a vital "touch point" for some patients with the health service and is therefore a valuable opportunity for members of the perioperative team to promote optimal lifestyle choices, such as the notion and importance of healthy eating not just for surgery but also for long-term health benefit.

A Decade of Dietary Assessment Methodology Research at the National Institutes of Health, 2012-2021

BACKGROUND

Assessment of individual and population-level dietary intake is critical for public health surveillance, epidemiology, and dietary intervention research. In recognition of that need, the National Insitutes of Health (NIH) has a history of funding research projects designed to support the development, implementation, and refinement of tools to assess dietary intake in humans.

OBJECTIVES

This report provides data and information on NIH-funded dietary intake assessment methodological research over the period of 2012-2021.

METHODS

Data were extracted from an internal NIH data system using the Research, Condition, and Disease Categorization (RCDC) spending category for Nutrition. Data were then examined to identify research focused on dietary assessment tools or methods to capture or analyze dietary intake.

RESULTS

Over the decade of 2012-2021, NIH supported 46 grants and 2 large contracts specific to dietary assessment methods development. The top 6 Institutes and Offices funding dietary assessment methods research were identified. Most projects were limited to adults. Projects ranged from novel methods to capture dietary intake, and refinement of analytical methods, to biomarkers of dietary intake. One key contract supported the automated self-administered 24-h dietary assessment tool (ASA24), a widely used, free tool available to the research community for assessing dietary intake.

CONCLUSIONS

NIH's support for dietary assessment methods development over this 10-y period was small but grew over time with an expanding number and variety of methods, data sources, and technological advancements in the assessment of dietary intake. NIH remains committed to supporting research seeking to advance the field of dietary assessment methods research.

Association between Late-Eating Pattern and Higher Consumption of Ultra-Processed Food among Italian Adults: Findings from the INHES Study

Late eating is reportedly associated with adverse metabolic health, possibly through poor diet quality. We tested the hypothesis that meal timing could also be linked to food processing, an independent predictor of health outcomes. We analysed data on 8688 Italians (aged > 19years) from the Italian Nutrition & HEalth Survey (INHES) established in 2010-2013 throughout Italy. Dietary data were collected through a single 24 h dietary recall, and the NOVA classification was used to categorize foods according to increasing levels of processing: (1) minimally processed foods (e.g., fruits); (2) culinary ingredients (e.g., butter); (3) processed foods (e.g., canned fish); (4) ultra-processed foods (UPFs; e.g., carbonated drinks, processed meat). We then calculated the proportion (%) of each NOVA group on the total weight of food eaten (g/d) by creating a weight ratio. Subjects were classified as early or late eaters based on the population's median timing for breakfast, lunch and dinner. In multivariable-adjusted regression models, late eaters reported a lower intake of minimally processed food (β = -1.23; 95% CI -1.75 to -0.71), a higher intake of UPF (β = 0.93; 0.60 to 1.25) and reduced adherence to a Mediterranean Diet (β = -0.07; -0.12 to -0.03) as compared to early eaters. Future studies are warranted to examine whether increased UPF consumption may underpin the associations of late eating with adverse metabolic health reported in prior cohorts.

Extended Inter-Meal Interval Negatively Impacted the Glycemic and Insulinemic Responses after Both Lunch and Dinner in Healthy Subjects

This study aimed to investigate the glycemic and insulinemic effects of lunch timing based on a fixed feeding window, and the effects of apple preload on postprandial glucose and insulin responses after nutrient-balanced lunch and the subsequent high-fat dinner in healthy participants. Twenty-six participants completed four randomized, crossover experimental trials: (1) early standardized lunch at 12:00 (12S); (2) apple preload to 12S (12A+S); (3) late standardized lunch at 14:00 (14S); and (4) apple preload to 14S (14A+S); wherein twenty participants’ blood samples were collected for insulin analysis following the lunch trails. In each experimental trial, each participant equipped with a continuous glucose monitor (CGM) was provided with a standardized breakfast and a high-fat dinner to be consumed at 8:00 and 18:00, respectively. The late lunch (14S) resulted in significantly elevated glucose peak, delayed insulin peak time, decreased insulin sensitivity, and increased insulin resistance following the lunch; also decreased glycemic response following the subsequent dinner and larger blood glucose fluctuation over the 24-h period compared with the 12S. The 14A+S significantly reduced the glucose peak, the insulin peak time and the glycemic variability following the lunch, also the 24-h glycemic variability compared with the 14S. The insulin sensitivity was significantly improved in the 12A+S, compared with that of the 12S. In conclusion, the present study found that an extra 2-h inter-meal fasting before and after lunch resulted in elevated glycemic response in both macronutrient-balanced meal and high-fat meal in healthy subjects. The negative impact of a late lunch could be partly reversed by the apple preload, without a trade-off of insulin secretion.

Frequency of Eating in the US Population: A Narrative Review of the 2020 Dietary Guidelines Advisory Committee Report

Background

A person's daily nutrient intake and overall nutritional status are determined by a complex interplay of the types and amounts of foods ingested in combination with the timing and frequency of eating.

Objectives

The aim was to summarize frequency of eating occasion data examined by the 2020 Dietary Guidelines Advisory Committee, the macronutrient contributions they provide, and meal frequency relative to dietary quality among the US population (≥2 y), with a focus on sex, age, race/Hispanic origin, and income.

Methods

Demographic and 24-h recall data from the 2013-2016 NHANES were examined. An eating occasion was defined as "any ingestive event (e.g., solid food, beverage, water) that is either energy yielding or non-energy yielding"; all eating occasions were further divided into discrete meals and snacks. Frequency of meals and snacks was defined as "the number of daily EOs [eating occasions]," respectively. Diet quality was assessed via the Healthy Eating Index (HEI)-2015.

Results

Most Americans consume 2 (28%) to 3 (64%) meals on a given day and >90% consume 2 to 3 snacks on that day. Adult, Hispanic, and non-Hispanic Black and lower-income (<131% family poverty-to-income ratio) Americans had a lower frequency of eating than children or adolescents, non-Hispanic White, and non-Hispanic Asian Americans and higher-income Americans, respectively. Americans who reported 3 meals on a given day consumed a diet higher in dietary quality than Americans who consumed 2 meals on a given day (HEI-2015: 61.0 vs. 55.0), regardless of population subgroup.

Conclusions

The frequency of the types of eating occasions differs according to age, race and Hispanic origin, and income. Dietary quality is associated with the number of meals consumed. Healthy dietary patterns can be constructed in a variety of ways to suit different life stages, cultural practices, and income levels; improved diet quality and careful consideration of nutrient density when planning meals are warranted.

Sustained effect of habitual feeding time on daily rhythm of core body temperature in mice

Background and aim

Circadian clocks in most peripheral tissues are entrained mainly by feeding. Therefore, this study aimed to investigate whether the daily rhythm of core body temperature (CBT), including the effect of diet-induced thermogenesis, varies according to habitual feeding time.

Methods

Wild-type and uncoupling protein 1 (UCP1) knockout mice were fed only during the first 4 h (Breakfast group) or the last 4 h of the dark period (Dinner group) for 17 days. On day 18, both groups were fed twice for 2 h, at the same starting times. Locomotor activity and CBT were measured continuously during the experiment.

Results

On day 18, CBT increased at the beginning of each feeding period, regardless of the group and strain. However, the CBT increase induced by the first meal decreased sharply in the Breakfast group and mildly in the Dinner group; the opposite was observed after the second meal. In UCP1 knockout, but not wild-type, mice, the total amount of CBT was significantly lower in the Dinner group than in the Breakfast group. These effects were mostly independent of the locomotor activity and food intake.

Conclusion

These results reveal that the effect of habitual feeding time on the daily rhythm of CBT is sustained at least until the following day. These effects may be mediated by both UCP1-dependent and -independent mechanisms.