Eating patterns of US adults: Meals, snacks, and time of eating

Time-restricted eating affects human adipose tissue fat mobilization

OBJECTIVE

Time-restricted eating (TRE), a dietary approach that confines food intake to specific time windows, has shown metabolic benefits. However, its impact on body weight loss remains inconclusive. The objective of this study was to investigate the influence of early TRE (eTRE) and delayed TRE (dTRE) on fat mobilization using human adipose tissue (AT) cultures.

METHODS

Subcutaneous AT was collected from 21 participants with severe obesity. We assessed fat mobilization by measuring glycerol release in AT culture across four treatment conditions: control, eTRE, dTRE, and 24-h fasting.

RESULTS

TRE had a significant impact on lipolysis (glycerol release [mean (SD)] in micromoles per hour per gram: control, 0.05 [0.003]; eTRE, 0.10 [0.006]; dTRE, 0.08 [0.005]; and fasting, 0.17 [0.008]; p < 0.0001). Both eTRE and dTRE increased lipolysis compared with the control group, with eTRE showing higher glycerol mobilization than dTRE during the overall 24-h time window, especially at the nighttime/habitual sleep episode (p < 0.0001). Further analysis of TRE based on fasting duration revealed that, independently of the time window, glycerol release increased with fasting duration (in micromoles per hour per gram: 8 h = 0.08 [0.001]; 12 h = 0.09 [0.008]; and 16 h of fasting = 0.12 [0.011]; p < 0.0001).

CONCLUSIONS

This study provides insights into the potential benefits of TRE on fat mobilization and may guide the design of future dietary strategies for weight management and metabolic health.

The impact of exercise on food-related inhibitory control- do calories, time of day, and BMI matter? Evidence from an event-related potential (ERP) study

A growing body of research suggests exercise improves inhibitory control functions. We tested if exercise-related inhibitory control benefits extend to food-related inhibitory control and differ by calorie content, time of day, and weight status. One hundred thirty-eight individuals were pseudo-randomly assigned to a morning or evening group. Each subject participated in two lab sessions where they completed questionnaires (rest session) or walked on a treadmill at 3.8mph (exercise session) for 45 min. After each session, participants completed both a high-calorie and low-calorie go/no-go task while N2 and P3 event-related potentials (ERP), both neural indicators of inhibitory control, were measured. Participants also rated food images for valence and arousal. While N2 and P3 difference amplitudes were larger to high-calorie than low-calorie foods, neither exercise nor time of day affected results. Individuals had faster response times after exercise without decreases in accuracy. Arousal and valence for high-calorie foods were lower after exercise and lower for all foods after morning compared to evening exercise. In a subset of individuals with obesity and normal-weight individuals, individuals with obesity had larger N2 difference amplitudes after morning exercise, while normal-weight individuals had larger P3 difference amplitudes to high-calorie foods after exercise. Results suggest moderate exercise did not affect food-related inhibitory control generally, although morning exercise may be beneficial in improving early recruitment of food-related inhibitory control in individuals with obesity. Moderate exercise, particularly in the morning, may also help manage increased attention allocated to food.

Indices of Sleep Health Are Associated With Timing and Duration of Eating in Young Adults

BACKGROUND

Limited data exist examining whether timing and/or duration of eating behaviors throughout the day affect sleep health.

OBJECTIVE

The aim of this study was to identify the relationship between eating behaviors and sleep in young adults without chronic diseases or conditions.

DESIGN

This was a cross-sectional study using 7 days of baseline data from a randomized crossover trial.

PARTICIPANTS/SETTING

Participants included 52 young adults. The study took place in West Lafayette, Indiana, between April 2017 and May 2018.

MAIN OUTCOME MEASURES

Timing and duration of eating were assessed via 3 nonconsecutive, 24-hour dietary recalls. Bedtime, wake time, total sleep time, sleep latency, sleep efficiency, and wake after sleep onset were measured over 7 days via wrist actigraphy and sleep diaries.

STATISTICAL ANALYSES PERFORMED

Two-way analyses of variance were applied to assess group differences based on timing of consumption (early vs late eating) and duration of eating (long: >13 hours, short: <11 hours, or standard: 11-13 hours) with post-hoc pairwise comparisons.

RESULTS

Main effects of timing of consumption, but not duration of eating, were detected for wake time, bedtime, and sleep efficiency (all, P < .05). Specifically, participants with later eating patterns that included breakfast skipping had later wake times and later bedtimes than those with earlier eating patterns. In addition, those who had later eating patterns that included breakfast skipping and nighttime eating experienced lower sleep efficiency (mean [SE], 77.0% [2.3%]) vs those who consumed breakfast and no nighttime eating (mean [SE], 84.6% [1.4%]; P < .001) and those who skipped breakfast but had no nighttime eating (mean [SE], 84.2% [2.5]; P < .05). Those who consumed breakfast but also had nighttime eating had a mean (SE) sleep efficiency of 82.4% (1.4%) (P = .09).

CONCLUSIONS

The timing of eating was associated with sleep-wake onset and sleep efficiency. This study provides the preliminary characterization of eating behaviors relative to sleep-wake cycles and highlights the need for experimental studies to understand whether manipulating the timing of eating occasions to better align with sleep-wake cycles could improve sleep health.

Evaluation of daily eating patterns on overall diet quality using decision tree analyses

BACKGROUND

Preliminary evidence suggests that meal timing is associated with higher quality diets. Less is known about whether types of food consumed during specific eating episodes (i.e., day-level eating patterns) predict diet quality.

OBJECTIVES

We investigated the association between day-level eating patterns and diet quality.

METHODS

Decision tree models were built using 24-h dietary recall data from the National Health and Nutrition Examination Survey 2015 and 2017 cycles in a cross-sectional study. Sixteen food groups and 12 eating episodes (e.g., breakfast, lunch) were included as input parameters. Diet quality was scored using the Healthy Eating Index-2020 and categorized as higher or lower quality diets based on the median score. Mean decrease in impurity (MDI) ± standard deviation determined the relative contribution that day-level eating patterns had on diet quality; higher values represented greater contributions.

RESULTS

We analyzed 12,597 dietary recalls from 9347 United States adults who were aged 18 y and older with ≥1 complete recall. Meals (breakfast, lunch, dinner) and respective snacking episodes had the greatest variety of dietary groups that contributed to the Healthy Eating Index-2020 score. Any whole-grain intake at breakfast predicted a higher quality diet (MDI = 0.08 ± 0.00), followed by lower solid fat intake (<8.94 g; MDI = 0.07 ± 0.00) and any plant protein intake at dinner (MDI = 0.05 ± 0.00).

CONCLUSIONS

Day-level eating patterns were associated with diet quality, emphasizing the relevance of both food type and timing in relation to a high-quality diet. Future interventions should investigate the potential impact of targeting food type and timing to improve diet quality.

Chrononutrition and Cardiometabolic Health: An Overview of Epidemiological Evidence and Key Future Research Directions

Chrononutrition is a rapidly evolving field of nutritional epidemiology that addresses the complex relationship between temporal eating patterns, circadian rhythms, and metabolic health, but most prior research has focused on the cardiometabolic consequences of time-restricted feeding and intermittent fasting. The purpose of this topical review is to summarize epidemiological evidence from observational and intervention studies regarding the role of chrononutrition metrics related to eating timing and regularity in cardiometabolic health preservation and cardiovascular disease prevention. Observational studies are limited due to the lack of time-stamped diet data in most population-based studies. Findings from cohort studies generally indicate that breakfast skipping or the later timing of the first eating occasion, a later lunch and dinner, and a greater proportion of caloric intake consumed in the evening are associated with adverse cardiometabolic outcomes, including higher risk for coronary heart disease, hypertension, type 2 diabetes, obesity, dyslipidemia, and systemic inflammation. Randomized controlled trials are also limited, as most in the field of chrononutrition focus on the cardiometabolic consequences of time-restricted feeding. Overall, interventions that shift eating timing patterns to earlier in the day and that restrict evening caloric intake tend to have protective effects on cardiometabolic health, but small sample sizes and short follow-up are notable limitations. Innovation in dietary assessment approaches, to develop low-cost validated tools with acceptable participant burden that reliably capture chrononutrition metrics, is needed for advancing observational evidence. Culturally responsive pragmatic intervention studies with sufficiently large and representative samples are needed to understand the impact of fixed and earlier eating timing schedules on cardiometabolic health. Additional research is warranted to understand the modifiable determinants of temporal eating patterns, to investigate the role of chrononutrition in the context of other dimensions of diet (quantity, quality, and food and nutrition security) in achieving cardiometabolic health equity, and to elucidate underlying physiological mechanisms.

Self-Reported Weekend Temporal Eating Patterns of American Adults Differ From Weekday: National Health and Nutrition Examination Surveys: 2015-2020 Prepandemic

BACKGROUND

Weekend-weekday differences in time of ingestive events may be implicated in adverse metabolic and health outcomes. However, little is known about the nature of weekend-weekday differences in temporal eating behaviors of the US adult population.

OBJECTIVE

The study aimed to examine weekend-weekday differences in temporal and energy characteristics of ingestive events self-reported by American adults.

DESIGN

Observational; within-person comparative.

PARTICIPANTS/SETTING

The data were from the National Health and Nutrition Examination Surveys (NHANES) 2015-March 2020 (pre-pandemic) for ≥20-year-old adults who provided 1 weekday (M-Th) and 1 weekend (F, S, Su) 24-h dietary recall (n = 3564 men and 3823 women).

MAIN OUTCOME MEASURES

Prespecified primary temporal outcomes were recalled: time of ingestive events, and the duration of ingestive and fasting windows. Secondary outcomes included frequency and energy characteristics of ingestive events.

STATISTICAL ANALYSIS PERFORMED

Gender-specific, survey-weighted, multiple linear regression models that accounted for complex survey design with dummy covariates for weekend/weekday, mode of recall administration (in-person on day 1 and telephone on day 2), and a respondent-specific fixed intercept.

RESULTS

In both men and women, the weekend recalled time of first ingestive event, breakfast, and lunch were later than weekday (P ≤ .0008); however, no statistically significant differences were observed in time of dinner and the last eating episode. The mean weekend ingestive window (interval between the time of first and last eating events of the day) was shorter by 24 minutes (95% confidence interval [CI], -32, -11) in men and 18 minutes (95% CI, -20, -15) in women, and the mean overnight fasting window was correspondingly longer (P ≤ .0001). No statistically significant differences were observed between weekend and weekday frequency of ingestive events. Energy density of weekend food selections reported by women, and of beverages by men, was found to be higher than weekday (P ≤ .002).

CONCLUSIONS

Weekend ingestive patterns were characterized by later time of first ingestive event, breakfast, and lunch, and selection of higher-energy-density foods and beverages.

Dynamics of self-control during choice and post-choice consumption quantity

Observed choices between options representing a relative vice and a relative virtue have commonly been used as a measure of eating self-control in the literature. However, even though self-control operations may manifest across the post-choice consumption stage, either similarly or in different ways from the choice stage, most prior research has ignored consumption quantity of the chosen option. While the behavior of choosing a virtue instead of a vice does manifest self-control, we examine how this plays out in post-choice consumption. Specifically, we find that when processing resources are limited, after having chosen a virtue food, unrestrained eaters ironically consumed greater quantities and therefore more calories than restrained eaters (Study 1). This reflects more persistent self-control in the post-choice consumption stage among restrained eaters than unrestrained eaters, and occurs because choosing a virtue lowers accessibility of the self-control goal among unrestrained eaters relative to restrained eaters (Study 2), thereby increasing intake of the virtuous food. In contrast, subsequent to having chosen a vice, unrestrained eaters and restrained eaters did not show any such difference in intake (Study 1) or goal accessibility (Study 2). Together, these results reveal that persistence of self-control in the post-choice consumption stage depends on individuals' dietary restraint and their initial exercise of self-control in the choice decision. The mere act of choosing a virtue satisfies unrestrained eaters' self-control goal and leads to increased food intake, whereas the same act keeps the same goal activated among restrained eaters who reduce intake of the chosen virtue. Put differently, persistent self-control across choice and quantity decisions is observed only when those with a dietary goal show successful self-control enactment in the choice stage. We therefore highlight that the operation of self-control can be dynamic within a consumption episode, and thus, choice and post-choice quantity are both informative of self-control.

Construct validity and test-retest reliability of a chrononutrition questionnaire for shift work and non-shift work populations

The irregular eating patterns of both shift workers and evening chronotypes adversely affect cardiometabolic health. A tool that conveniently captures temporal patterns of eating alongside an indicator of circadian rhythm such as chronotype will enable researchers to explore relationships with diverse health outcome measures. We aimed to investigate the test-retest reliability and convergent validity of a Chrononutrition Questionnaire (CNQ) that captures temporal patterns of eating and chronotype in the general population (non-shift workers, university students, retirees, unemployed individuals) and shift work population. Participants attended two face-to-face/virtual sessions and completed the CNQ and food/sleep/work diaries. Outcomes included subjective chronotype, wake/sleep/mid-sleep time, sleep duration, meal/snack regularity, meal/snack/total frequency, times of first/last/largest eating occasions (EO), main meal (MM) 1/2/3, and duration of eating window (DEW). 116 participants enrolled (44.5 ± 16.5 years, BMI: 27.3 ± 5.8 kg/m2, 73% female, 52% general population); 105 completed the study. Reliability was acceptable for chronotype, sleep, and all temporal eating patterns except on night shifts. Convergent validity was good for chronotype and sleep except for certain shift/shift-free days. Generally, meal/snack regularity and frequency, and times of first/last EO showed good validity for the general population but not shift workers. Validity was good for DEW (except work-free days and afternoon shifts) and times of MM 1/2/3 (except afternoon and night shifts), while time of largest EO had poor validity. The CNQ has good test-retest reliability and acceptable convergent validity for the general and shift work population, although it will benefit from further validation, especially regarding regularity, frequency, and times of first and last eating occasions across more days amongst a larger sample size of shift workers. Use of the CNQ by researchers will expand our current understanding of chrononutrition as relationships between timing of food intake and the multitude of health outcomes are examined.

Daily Duration of Eating for Children and Adolescents: A Systematic Review and Meta-Analysis

Time-limited eating is a dietary intervention whereby eating is limited to a specific window of time during the day. The usual eating windows of adults, and how these can be manipulated for dietary interventions, is well documented. However, there is a paucity of data on eating windows of young people, the manipulation of which may be a useful intervention for reducing obesity. This paper reviewed the existing literature on the eating windows of children and adolescents, aged 5-18 years, plus clock times of first and last intakes and variations by subgroup. Two databases (Medline and Embase) were searched for eligible papers published between February 2013 and February 2023, with forward searching of the citation network of included studies on Web of Science. Articles were screened, and data extracted, in duplicate by two independent reviewers. Ten studies were included, with both observational and experimental designs. Narrative synthesis showed large variations in eating windows with average values ranging from 9.7 h to 16.4 h. Meta-analysis, of five studies, showed a pooled mean daily eating window of 11.3 h (95% CI 11.0, 11.7). Large variations in eating windows exist across different study populations; however, the pooled data suggest that it may be possible to design time-limited eating interventions in paediatric populations aimed at reducing eating windows. Further high-quality research, investigating eating windows and subsequent associations with health outcomes, is needed.

The effect of time of eating on cardiometabolic risk in primary and secondary prevention of cardiovascular disease

Continuous energy restriction is currently considered the first-line dietary therapy for weight loss in individuals with obesity. Recently, interventions which alter the eating window and time of eating occasions have been explored as means to achieve weight loss and other cardiometabolic improvements such as a reduction in blood pressure, glycaemia, lipids and inflammation. It is unknown, however, whether these changes result from unintentional energy restriction or from other mechanisms such as the alignment of nutrient intake with the internal circadian clock. Even less is known regarding the safety and efficacy of these interventions in individuals with established chronic noncommunicable disease states, such as cardiovascular disease. This review examines the effects of interventions which alter both eating window and time of eating occasions on weight and other cardiometabolic risk factors in both healthy participants and those with established cardiovascular disease. We then summarise the state of existing knowledge and explore future directions of study.

Effect of Intermittent Fasting on Cardiometabolic Health in the Chinese Population: A Meta-Analysis of Randomized Controlled Trials

The efficacy of intermittent fasting (IF), as an emerging weight management strategy, in improving cardiometabolic health has been evaluated in various populations, but that among Chinese individuals has not been systematically studied. A comprehensive search on multiple databases was performed to identify eligible randomized controlled trials (RCTs) up to October 2022. The primary outcome was post-intervention weight loss, and secondary outcomes included changes in cardiometabolic indicators. Effect estimates were meta-analyzed using a random-effects model. In total, nine RCTs with 899 Chinese participants were included. Time-restricted eating was the most adopted IF protocol in this study (six out of nine), followed by alternate-day fasting. The IF intervention significantly reduced body weight, body mass index, body fat mass, homeostatic model assessment of insulin resistance, low-density lipoprotein cholesterol, and triglycerides when compared with control groups. However, no statistically significant reductions in waist circumference, total cholesterol, high-density lipoprotein cholesterol, fasting glucose, systolic blood pressure, and diastolic blood pressure were found. To sum up, IF can be a weight management strategy and may improve the cardiometabolic health of Chinese adults, but more long-term trials using different IF strategies are required to generate robust evidence of its efficacy.

Gut microbes modulate (p)ppGpp during a time-restricted feeding regimen

IMPORTANCE

Mammals do not eat continuously, instead concentrating their feeding to a restricted portion of the day. This behavior presents the mammalian gut microbiota with a fluctuating environment with consequences for host-microbiome interaction, infection risk, immune response, drug metabolism, and other aspects of health. We demonstrate that in mice, gut microbes elevate levels of an intracellular signaling molecule, (p)ppGpp, during the fasting phase of a time-restricted feeding regimen. Disabling this response in a representative human gut commensal species significantly reduces colonization during this host-fasting phase. This response appears to be general across species and conserved across mammalian gut communities, highlighting a pathway that allows healthy gut microbiomes to maintain stability in an unstable environment.

Comparison of Meal Patterns Across Common Racial Groups in the UK and the USA, Examining Associations with Weight Status and Diet Quality: a Secondary Analysis of NDNS and NHANES Datasets

OBJECTIVE

Understanding diets of population subgroups is essential for monitoring health of diversifying populations, but currently, meal patterns of many population subgroups are not widely known. This paper aimed to identify meal patterns of racial groups in the UK and USA, considering if racial groups exhibit similar patterns of intake irrespective of location and relationships between meal patterns and health parameters.

DESIGN

Data were extracted from the UK (National Diet and Nutrition Survey) and the USA (National Health and Nutrition Examination Survey) national dietary surveys. Temporal and content meal patterns among racial groups in the UK and USA (White, Black, Asian and Other, n = 1780 and n = 4339, respectively) were examined. Kruskal-Wallis tests were applied to understand differences across groups. Logistic regression models identified associations between meal patterns and body mass index and diet quality.

RESULTS

Black groups consumed fewer eating occasions than White and Other groups in both countries, while UK racial groups consumed significantly more snacks than USA groups. Food group contribution to eating occasion consumption was similar across countries where Asian groups in the USA and UK had the lowest meat intake at lunch and dinner. Meal frequency was positively associated with diet quality.

CONCLUSIONS

Overall, meal patterns differ across racial groups within a single country, and some differences were observed within groups of the same race across countries. Learnings from this research highlight the differences in consumption patterns across racial groups and the importance of considering a meal-based approach to dietary guidelines by racial group.

Effects of dietary inflammatory index, blood lead levels, and flavonoid intake on stroke risk in older Americans: A cross-sectional study

OBJECTIVES

We aimed to investigate the relationship between dietary flavonoids, the dietary inflammatory index (DII), blood lead levels, and stroke and evaluate how these factors interact with one another in relation to stroke.

MATERIALS AND METHODS

We analyzed data from 3675 older American adults aged ≥60 years, obtained from the National Health and Nutrition Examination Survey. Since this database does not specifically differentiate between hemorrhagic and ischemic strokes, our data include both types. We utilized the DII to assess the inflammatory potential of the diet, calculated using 24 h dietary recalls. To determine the association between dietary flavonoids, blood lead levels, DII, and stroke, we performed multivariate logistic regression, subgroup analysis, and restricted cubic splines. We modeled additive interactions to assess the relationship between blood lead levels and DII.

RESULTS

A high intake of flavonols, flavan-3-ols, and total flavonoids correlated negatively with stroke risk, whereas blood lead levels had a positive association. After adjusting for confounders, stroke risk was found to increase with higher DII. Restricted cubic splines analysis revealed that flavan-3-ols, total flavonoids, blood lead levels, and DII were linearly related to stroke, while the relationships with flavonoids and flavonols were nonlinear. Additionally, a significant interaction was detected between high DII and elevated blood lead levels in relation to stroke risk.

CONCLUSIONS

Intake of flavan-3-ol, flavanols, and total flavonoids is negatively associated with stroke risk, while higher blood lead levels and DII are positively related to it. High DII and elevated blood lead levels interact synergistically to influence stroke risk.

Snacks contribute considerably to total dietary intakes among adults stratified by glycemia in the United States

Little is known about the snacking patterns among adults with type 2 diabetes. The contribution of snacks to energy and nutrient intakes is important to further understand dietary patterns and glycemic control. The purpose of this study is to evaluate snack consumption among adults according to diabetes status in the United States. One NHANES 24-hour dietary recall for each participant collected between 2005-2016 was utilized for analysis (n = 23,708). Analysis of covariance was used to compare differences in nutrient and food groups intakes from snacks across levels of glycemic control, while controlling for age, race/ethnicity, income, marital status, and gender. Results of this analysis inform that adults with type 2 diabetes consume less energy, carbohydrates, and total sugars from snacks than adults without diabetes. Those with controlled type 2 diabetes consumed more vegetables and less fruit juice than other groups, yet adults with type 2 diabetes in general consumed more cured and luncheon meats than adults without diabetes or with prediabetes. Protein from all snacks for those without diabetes is higher than all other groups. This study elucidates common snacking patterns among US adults with diabetes and highlights the need for clinicians and policymakers to take snacking into consideration when evaluating and providing dietary recommendations.

Acute effects of daily step count on postprandial metabolism and resting fat oxidation: a randomized controlled trial

To examine the effects of daily step count on same-day fat oxidation and postprandial metabolic responses to an evening high-fat mixed meal (HFMM). Ten healthy participants (5 females, 30 ± 7 yr) completed four different daily step counts-2,000 (2 K), 5,000 (5 K), 10,000 (10 K), and 15,000 (15 K) steps-on separate days in randomized order. On experimental days, participants ate the same meals and walked all steps on an indoor track at a pace of 100 steps/min in three roughly equal bouts throughout the day. After the final walking bout, participants' resting energy expenditure (REE), respiratory exchange ratio (RER), and fat oxidation rate (FATOX) were measured. Blood samples were obtained before (BL) and 30-, 60-, 90-, 120-, and 240-min following consumption of an HFMM (960 kcal; 48% fat) to measure triglycerides (i.e., postprandial lipemia; PPL), nonesterified fatty acids (NEFAs), insulin, and glucose. Two-way ANOVAs indicated condition effects where PPL was significantly higher after 2 K versus 10 K (+23 ± 8 mg/dL, P = 0.027), and NEFAs were significantly higher after 15 K versus 2 K (+86 ± 23 µmol/L; P = 0.006). No differences were found for insulin, glucose, or REE among conditions (all P > 0.124). Similarly, RER (P = 0.054; ηp2 = 0.24) and FATOX (P = 0.071; ηp2 = 0.23) were not significantly different among conditions. In young adults, 10 K steps elicited the greatest decrease in PPL, an established cardiovascular disease risk factor. NEFA levels were highest after the 15 K condition, likely due to alterations in adipose tissue lipolysis or lipoprotein lipase activity with increased activity.NEW & NOTEWORTHY This randomized controlled trial demonstrated that walking 10,000, compared with 2,000, steps/day significantly reduced postprandial lipemia (PPL), an independent predictor of cardiovascular disease (CVD) following same-day evening meal consumption. These experimental data support walking 10,000 steps/day to lower CVD risk.

The psychological basis of hunger and its dysfunctions

This article describes a new and emerging psychological perspective on hunger, together with the implications of that perspective, which is based upon learning and memory. Hunger is a psychological state characterized by a desire to eat. Historically, conceptions of hunger have largely been expressed in terms of physiology (eg, biological process X causes hunger). However, physiology neither offers a psychological account of hunger nor explains why memory impairment can eliminate hunger. Two forms of hunger are identified - specific and general. Specific hunger is for particular palatable foods. It involves recollecting episodic memories of eating that food, when an associated cue is encountered (eg, an advert). General hunger is a desire to eat triggered by temporal (eg, it is lunchtime) or interoceptive (eg, tummy rumble) cues. It involves semantic memory retrieval, which then augments the expected - remembered - pleasure for any food. Both hungers are supported by the medial temporal lobe memory system. Damage to this system can occur from eating a Western-style diet and, longer-term, from obesity and its consequences. Medial temporal lobe memory damage may cause deficits in specific hunger, but most especially in general hunger, resulting in little motivation to eat foods that the individual considers to be of low-to-moderate palatability, such as fruit and vegetables. The implications of this account for teaching people hunger, for how hunger is affected by diet, for public education, and pharmaceutical intervention, are discussed. Psychological concepts of hunger are widely used in nutritional practice. This article provides a new and emerging perspective on the psychological basis of hunger and its implications.

Impact of Nighttime Food Consumption and Feasibility of Fasting during Night Work: A Narrative Review

Shift work has been associated with an increased risk of developing chronic non-communicable diseases, such as obesity. The reduction in overnight fasting and its physiological consequences seem to affect the metabolic health of shift workers, but little has been discussed regarding the feasibility and implications of maintaining a night-long fast during work. This narrative review aims to discuss the impact of eating behavior on the reduction of overnight fasting in shift workers, as well as possible nutritional strategies involving fasting that have been tested for shift workers, to contribute to the establishment of nutritional guidelines for them. We used various databases and search engines to retrieve relevant articles, reviews, and investigations. Despite the potential benefits of overnight fasting for other groups, few studies have investigated this approach in the context of shift work. Generally, it seems to be a feasible and metabolically beneficial strategy for shift workers. However, it is essential to investigate the potential risks and benefits of reducing the fasting time for shift workers, considering social, hedonic, and stress-related factors. Furthermore, randomized clinical trials are necessary to establish safe and feasible strategies for shift workers to practice different fasting windows.

Influence of fasting during the night shift on next day eating behavior, hunger, and glucose and insulin levels: a randomized, three-condition, crossover trial

AIMS

To investigate the influence of fasting during the night shift on eating behavior, hunger, glucose and insulin levels the following day.

METHODS

Study with 10 male police officers who have been working at night. Participants were tested under three different conditions separated by at least 6 days of washout in a randomized, crossover design: "Night Shift Fasting" (NSF)-two nights of fasting during the night shift; "Night Shift Eating" (NSE)-two nights with the consumption of a standardized meal during the night shift (678 ± 42 kcal consumed at ~ 0200 h); and "Nighttime Sleep" (NS)-two nights of sleep. The morning after, blood glucose and insulin and hunger ratings were assessed, and food intake was assessed with an ad libitum test meal. Food intake was also assessed throughout the remainder of the day using a food record. Generalized Estimating Equations were used to analyze the effect of experimental condition.

RESULTS

Food intake during the test meal, especially of proteins and fats, was higher after fasting during the night shift compared to the other conditions (p < 0.05), whereas desire to eat scores were lower after the NSF compared to NSE condition (p = 0.043). Hunger levels were lower after the NSF compared to the NS condition (p = 0.012). Insulin and HOMA-IR were also lower in the morning after NSF (p < 0.001).

CONCLUSION

Fasting during the night shift leads to not only a higher intake of energy and macronutrients both in the early morning after work and throughout the next day, but also lower insulin levels and HOMA-IR in the morning.

REGISTRATION NUMBER OF CLINICAL TRIAL

NCT03800732. Initial release: 01/09/2019. Last release: 02/23/2022.

Effects of Morning Vs. Evening exercise on appetite, energy intake, performance and metabolism, in lean males and females

Exercise is an important component of a weight management strategy. However, little is known about whether circadian variations in physiological and behavioural processes can influence the appetite and energy balance responses to exercise performed at different times of the day. This study compared the effects of morning and evening exercise on appetite, post-exercise energy intake, and voluntary performance. In randomised, counterbalanced order, 16 healthy males and females (n = 8 each) completed two trials, performing morning exercise at 10:30 (AMEx) or evening exercise at 18:30 (PMEx). Exercise consisted of 30 min steady-state cycling (60% V˙ O_2peak), and a 15-min performance test. A standardised meal (543 ± 86 kcal) was consumed 2-h before exercise and ad-libitum energy intake was assessed 15 min after exercise, with subjective appetite measured throughout. Absolute ad-libitum energy intake was 152 ± 126 kcal greater during PMEx (P < 0.001), but there was no differences in subjective appetite between trials immediately pre-exercise, or immediately before the post-exercise meal (P ≥ 0.060). Resting energy expenditure (P < 0.01) and carbohydrate oxidation (P < 0.05) were greater during AMEx, but there were no differences in substrate oxidation or energy expenditure during exercise (P ≥ 0.155). Exercise performance was not different between trials (P = 0.628). In conclusion, acute morning and evening exercise prompt similar appetite responses, but post-exercise ad-libitum energy intake is greater following evening exercise. These findings demonstrate discordant responses between subjective appetite and ad-libitum energy intake but suggest that exercise might offset circadian variations in appetite. Longer-term studies are required to determine how exercise timing affects adherence and weight management outcomes to exercise interventions. TRIAL REGISTRATION: NCT04742530, February 8, 2021.

Barriers to adherence in time-restricted eating clinical trials: An early preliminary review

Time-restricted eating (TRE) has shown potential benefits in optimizing the body's circadian rhythms and improving cardiometabolic health. However, as with all dietary interventions, a participant's ability to adhere to the protocol may be largely influenced by a variety of lifestyle factors. In TRE trials that reported participants' rates of adherence, the percentage of total days with successful adherence to TRE ranged from 47% to 95%. The purpose of this review is to (1) summarize findings of lifestyle factors affecting adherence to TRE clinical trials outside of the lab, and (2) explore a recommended set of behavioral intervention strategies for the application of TRE. A literature search on Pubmed was conducted to identify clinical TRE studies from 1988 to October 5, 2022, that investigated TRE as a dietary intervention. 21 studies included daily self-monitoring of adherence, though only 10 studies reported a combination of family, social, work, and miscellaneous barriers. To maximize participant adherence to TRE and increase the reliability of TRE clinical trials, future studies should monitor adherence, assess potential barriers, and consider incorporating a combination of behavioral intervention strategies in TRE protocols.

Chrononutrition is associated with melatonin and cortisol rhythm during pregnancy: Findings from MY-CARE cohort study

Chrononutrition has been suggested to have an entrainment effect on circadian rhythm which is crucial for metabolic health. Investigating how chrononutrition affects maternal circadian rhythm can shed light on its role during pregnancy. This study aims to determine chrononutrition characteristics of healthy primigravida during pregnancy and its association with melatonin and cortisol rhythm across gestation. A total of 70 healthy primigravidas were recruited from ten randomly selected government maternal and child clinics in Kuala Lumpur, Malaysia. During the second and third trimesters, chrononutrition characteristics including meal timing, frequency, eating window, breakfast skipping, and late-night eating were determined using a 3-day food record. Pregnant women provided salivary samples at five time-points over a 24 h period for melatonin and cortisol assay. Consistently across the second and third trimesters, both melatonin and cortisol showed a rhythmic change over the day. Melatonin levels displayed an increment toward the night whilst cortisol levels declined over the day. Majority observed a shorter eating window (≤12 h) during the second and third trimesters (66 and 55%, respectively). Results showed 23 and 28% skipped breakfast whereas 45 and 37% ate within 2 h pre-bedtime. During the third trimester, a longer eating window was associated with lower melatonin mean (β = -0.40, p = 0.006), peak (β = -0.42, p = 0.006), and AUC_G (β = -0.44, p = 0.003). During both trimesters, a lower awakening cortisol level was observed in pregnant women who skipped breakfast (β = -0.33, p = 0.029; β = -0.29, p = 0.044). Only during the second trimester, breakfast-skipping was significantly associated with a greater cortisol amplitude (β = 0.43, p = 0.003). Findings suggest that certain chrononutrition components, particularly eating window and breakfast skipping have a significant influence on maternal melatonin and cortisol rhythm. Dietary intervention targeting these characteristics may be useful in maintaining maternal circadian rhythm.

Contribution of Snacks to Dietary Intakes Stratified by Race/Ethnicity in the United States

BACKGROUND

Snacking recommendations do not exist, yet snacks contribute substantially to daily energy intakes. While dietary intakes of adults in the United States vary by race/ethnicity, little is known about their snacking patterns. The aim of this study was to assess the quality of snacks stratified by race/ethnicity in adults who participated in the 2011-2018 National Health and Nutrition Examination Survey (NHANES).

METHOD

Dietary data from 18,679 adults older than 19 years were assessed to examine differences in intakes from snacking occasions by self-identified race/ethnicity. Mean intakes were estimated for total snacking occasions, percentage of day, nutrient density per 100 kcals, and the average snack. Healthy Eating Index-2015 (HEI) scores were computed for intakes from total day, snack only, and meals only. Analysis of covariance assessed differences between racial/ethnic groups. US Department of Agriculture food categories determined sources of snack foods. Data were weighted to create a nationally representative sample.

RESULTS

Asians consumed the least amount of daily energy in the form of snacks, while Blacks and Whites consumed the most. Mean intakes of saturated fats and added sugars consumed during snacking occasions were significantly lowest in Asians, and highest in Blacks and Whites. While total and percentage of daily intakes of sodium were lowest in Asians during snacking occasions, they had significantly lowest meal-only HEI sodium subscore, indicating higher sodium consumption of sodium during mealtimes.

CONCLUSIONS

Diet quality of snacks varies significantly by race/ethnicity. These data support the need for development of snacking recommendations with culturally appropriate dietary interventions.

Infusion timing and sleep habits of adults receiving home parenteral and enteral nutrition: A patient-oriented survey study

BACKGROUND

The emerging field of chrononutrition investigates the effects of the timing of nutritional intake on human physiology and disease pathology. It remains largely unknown when patients receiving home nutrition support routinely administer home parenteral nutrition (HPN) and/or home enteral nutrition (HEN).

METHODS

The present descriptive study included data collected from a patient-oriented survey designed to assess the timing of infusions and sleep habits of patients receiving HPN and HEN in the United States.

RESULTS

A total of 100 patients were included. Patients had a mean age of 44.1 years and 81% were female. Among 73 patients supported with HPN and 27 patients supported with HEN, 86% and 44% reported overnight infusions, respectively. The median start and end times of overnight infusions were 2100 (interquartile range [IQR] = 1900-2200) and 0800 (IQR = 0700-1000), respectively, for HPN and 2000 (IQR = 1845-2137) and 0845 (IQR = 0723-1000), respectively, for HEN. Overnight infusions started 2.0 h (IQR = 1.1-3.0) and 2.0 h (IQR = 0.6-3.3) before bedtime for HPN and HEN, respectively, and stopped 12.9 min (IQR = -21.3 to 29.1) and 30.0 min (IQR = -17.1 to 79.3) after wake time for HPN and HEN, respectively. Sleep disruption because of nutrition support or urination was most common among patients receiving infusions overnight compared with those receiving infusions continuously or during the daytime.

CONCLUSIONS

Our survey study focusing on a novel and medically relevant dimension of nutrition found that most HPN-dependent and HEN-dependent patients receive infusions overnight while asleep. Our findings suggest that overnight infusions coinciding with sleep may result in sleep and circadian disruption.

Chrononutrition-When We Eat Is of the Essence in Tackling Obesity

Obesity is a chronic and relapsing public health problem with an extensive list of associated comorbidities. The worldwide prevalence of obesity has nearly tripled over the last five decades and continues to pose a serious threat to wider society and the wellbeing of future generations. The pathogenesis of obesity is complex but diet plays a key role in the onset and progression of the disease. The human diet has changed drastically across the globe, with an estimate that approximately 72% of the calories consumed today come from foods that were not part of our ancestral diets and are not compatible with our metabolism. Additionally, multiple nutrient-independent factors, e.g., cost, accessibility, behaviours, culture, education, work commitments, knowledge and societal set-up, influence our food choices and eating patterns. Much research has been focused on 'what to eat' or 'how much to eat' to reduce the obesity burden, but increasingly evidence indicates that 'when to eat' is fundamental to human metabolism. Aligning feeding patterns to the 24-h circadian clock that regulates a wide range of physiological and behavioural processes has multiple health-promoting effects with anti-obesity being a major part. This article explores the current understanding of the interactions between the body clocks, bioactive dietary components and the less appreciated role of meal timings in energy homeostasis and obesity.

Association of Dietary Fiber Intake With Myocardial Infarction and Stroke Events in US Adults: A Cross-Sectional Study of NHANES 2011–2018

This study aimed to detect dietary fiber intake and its association with nonfatal cardiovascular/cerebrovascular events (myocardial infarction and stroke) in adults in the United States. This cross-sectional study obtained data from the 2011–2018 National Health and Nutrition Examination Survey database. Using multivariate logistic regression, we compared dietary fiber intake across demographics and detected an association between dietary fiber intake and patient-reported nonfatal myocardial infarction and/or stroke events. We enrolled 8,872 participants (mean dietary fiber intake, 17.38 ± 0.22 g/day). The weighted prevalence of nonfatal cardiovascular/cerebrovascular events was 5.36%, which decreased with higher dietary fiber intake (nonfatal cardiovascular/cerebrovascular events: Tertile1, 6.50%; Tertile2, 5.45%; Tertile3, 4.25%). Higher fiber intake indicated a stable negative association with nonfatal cardiovascular/cerebrovascular events in the multivariate logistic regression analysis, weighted generalized additive model, and smooth curve fitting. Interaction tests showed no significant effect of demographic, socioeconomic, and disease status on the association between dietary fiber intake and nonfatal cardiovascular/cerebrovascular events. Dietary fiber intake was far below the recommended amount. Higher dietary fiber intake was associated with a lower prevalence of nonfatal cardiovascular/cerebrovascular events.

Eating patterns in a nationwide sample of Japanese aged 1-79 years from MINNADE study: eating frequency, clock time for eating, time spent on eating and variability of eating patterns

OBJECTIVE

Although there is growing evidence suggesting that eating patterns are important determinants of health status, comprehensive information on patterning of eating behaviours is almost lacking. The aim of this cross-sectional study was to describe eating patterns in Japan.

DESIGN

Information on actual eating behaviours was collected using 2-d dietary record in each season over a year (total 8 d). Eating occasions were defined as any discrete intake occasion (with a discrete start clock time and name) except for eating occasions consisting of water only, which were excluded.

SETTING

Japan.

PARTICIPANTS

A nationwide sample of 4032 Japanese aged 1-79 years.

RESULTS

The mean value of eating frequency of meals (i.e. breakfast, lunch and dinner), snacks and total eating occasions was 2·94, 1·74 and 4·68 times/d, respectively. The mean clock time for the start of breakfast, lunch and dinner was 07.24, 12.29 and 19.15 h, respectively. The mean time spent consuming breakfast, lunch, dinner and snacks was 19, 25, 34 and 27 min/d, respectively. On average, variability (i.e. average of absolute difference from mean) of meal frequency was small compared with that of snack frequency and total eating frequency. Both mean variability of clock time for the start of eating (<1 h) and mean variability of time spent on meals (<10 min/d) were also small. Conversely, mean variability of time spent on snacks was large (>18 min/d).

CONCLUSION

The present findings serve as both a reference and an indication for future research on patterning of eating behaviours.

Perspectives: on Precision Nutrition Research in Heart, Lung, and Blood Diseases and Sleep Disorders

The release of the 2020-2030 Strategic Plan for NIH Nutrition Research (SPNR) and its emphasis on precision nutrition has provided an opportunity to identify future nutrition research that addresses individual variability in response to diet and nutrition across the life span-including those relevant to the Strategic Vision of the National Heart, Lung, and Blood Institute (NHLBI). The SPNR and the NHLBI's Strategic Vision were developed with extensive input from the extramural research community, and both have 4 overarching strategic goals within which are embedded several objectives for research. For the SPNR, these include 1) spur discovery science and normal biological functions (e.g., role of the microbiome in health and disease), 2) population science to understand individual differences (e.g., biomarkers including 'omics that predict disease status), 3) emerging scientific areas of investigation and their application (e.g., data science, artificial intelligence), and 4) cross-cutting themes (e.g., training the scientific workforce and minority health and health disparities). These strategic goals and objectives serve as blueprints for research and training. Nutrition remains important in the prevention and treatment of heart, lung, blood, and sleep (HLBS) disorders and diseases, and the NHLBI has played a pivotal role in supporting nutrition research. In this paper, we report important gaps in the scientific literature related to precision nutrition in HLBS diseases. Research opportunities that could stimulate precision nutrition and their alignment with the SPNR and the NHLBI Strategic Vision Objectives are provided. These opportunities include 1) exploring individual differences in response to varying dietary patterns and nutrients; 2) investigating genetic/epigenetic, biological (e.g., microbiome, biomarkers), social, psychosocial, and environmental underpinnings of individual variability in diet; 3) elucidating the role of circadian rhythm and chrononutrition; and 4) applying implementation science research methods in precision nutrition interventions relevant to HLBS diseases.

Meal timing, distribution of macronutrients, and inflammation among African-American women: A cross-sectional study

Chronic low-grade inflammation is an underlying risk factor for numerous chronic diseases, including cancer. Eating earlier in the day has been associated with a reduction in levels of inflammatory markers and inflammation-related health outcomes (e.g., obesity, metabolic disorders). This cross-sectional study of 249 obese African-American women examined the effect of various mealtime-related factors associated with macronutrient consumption in relation to chronic inflammation and Breast Imaging Reporting and Data System (BI-RAD) readings. During 2011 and 2013, a single 24-hour dietary recall was administered, blood samples were assayed for c-reactive protein (CRP) and interleukin-6 (IL-6), and BI-RAD ratings were assessed to determine the influence of mealtime on chronic inflammation and breast cancer risk score. Multiple linear and logistic regression models were used to assess these relationships. Higher carbohydrate consumption at breakfast was associated with a significantly lower CRP vs. higher carbohydrate consumption at dinner (6.99, vs. 9.56 mg/L, respectively, p = .03). Additionally, every 1-unit increase in percent energy consumed after 5PM resulted in a BI-RAD reading indicating a possibly suspicious abnormality (OR: 1.053, 95% CI: 1.003-1.105), suggesting an increase in breast cancer risk. Timing of energy and macronutrient intake may have important implications for reducing the risk of diseases associated with chronic inflammation.

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

PURPOSE OF REVIEW

The aim of this short review is to provide an updated commentary on the current literature examining the impact of meal timing on obesity and weight gain in adults. The potential mechanisms, including novel and emerging factors, behind timing of food intake across the 24-h period in the development of obesity, and dietary strategies manipulating meal timing to ameliorate weight gain are also explored.

RECENT FINDINGS

Dietary patterns that feature meal timing outside of the regular daytime hours can contribute to circadian disruption as food is metabolised in opposition to internal daily rhythms and can feedback on the timekeeping mechanisms setting these rhythms. Epidemiological evidence examining the impact of late meal timing patterns is beginning to suggest that eating at night increases the risk of weight gain over time. Mechanisms contributing to this include changes to the efficiency of metabolism across the day, and dysregulation of appetite hormone and gut microbiota by mis-timed meals. When meals are eaten, in relation to the time of day, is increasingly considered of importance when implementing dietary change in order to address the growing burden of obesity, although further research is required in order to determine optimal patterns.

Interplay of Dinner Timing and MTNR1B Type 2 Diabetes Risk Variant on Glucose Tolerance and Insulin Secretion: A Randomized Crossover Trial

OBJECTIVE

We tested whether the concurrence of food intake and elevated concentrations of endogenous melatonin, as occurs with late eating, results in impaired glucose control, in particular in carriers of the type 2 diabetes-associated G allele in the melatonin receptor-1B gene (MTNR1B).

RESEARCH DESIGN AND METHODS

In a Spanish natural late-eating population, a randomized, crossover study was performed. Each participant (n = 845) underwent two evening 2-h 75-g oral glucose tolerance tests following an 8-h fast: an early condition scheduled 4 h prior to habitual bedtime ("early dinner timing") and a late condition scheduled 1 h prior to habitual bedtime ("late dinner timing"), simulating an early and a late dinner timing, respectively. Differences in postprandial glucose and insulin responses between early and late dinner timing were determined using incremental area under the curve (AUC) calculated by the trapezoidal method.

RESULTS

Melatonin serum levels were 3.5-fold higher in the late versus early condition, with late dinner timing resulting in 6.7% lower insulin AUC and 8.3% higher glucose AUC. The effect of late eating impairing glucose tolerance was stronger in the MTNR1B G-allele carriers than in noncarriers. Genotype differences in glucose tolerance were attributed to reductions in β-cell function (P for interaction, Pint glucose area under the curve = 0.009, Pint corrected insulin response = 0.022, and Pint disposition index = 0.018).

CONCLUSIONS

Concurrently high endogenous melatonin and carbohydrate intake, as typical for late eating, impairs glucose tolerance, especially in MTNR1B G-risk allele carriers, attributable to insulin secretion defects.

Characterisation of breakfast, lunch, dinner and snacks in the Japanese context: an exploratory cross-sectional analysis

OBJECTIVE

To characterise different meal types by examining the contribution of specific meals to the total intakes and the nutritional quality of each meal.

DESIGN

A cross-sectional analysis was conducted based on dietary data collected using 4-d dietary record. Diet quality was assessed by the Healthy Eating Index-2015 and Nutrient-Rich Food Index 9.3.

SETTING

Japan.

PARTICIPANTS

Adults aged 20-81 years (n 639).

RESULTS

Diet quality was, on average, highest for dinner, followed, in order, by lunch, breakfast and snacks. Breakfast, lunch, dinner and snacks, on average, accounted for 21 %, 32 %, 40 % and 11 % of total energy intake, respectively. For many nutrients, the percentage contribution to total intake did not vary within each meal, broadly in line with that for energy: 18-24 % for breakfast, 26-35 % for lunch, 35-49 % for dinner and 4-15 % for snacks. However, intakes of many foods largely depended on one meal type. The foods mainly eaten at dinner were potatoes, pulses, total vegetables, fish, meat and alcoholic beverages (52-70 %), in contrast to noodles (58 %) at lunch and bread (71 %) and dairy products (50 %) at breakfast. The foods mainly eaten at snacks were confectioneries (79 %) and sugar-sweetened beverages (52 %). Conversely, rice and eggs were more evenly distributed across three main meals (19-41 % and 30-38 %, respectively), while fruit and non-energetic beverages were more evenly distributed across all meal types (17-30 % and 19-35 %, respectively).

CONCLUSIONS

These findings provide the background information on each meal type in Japanese and may help inform the development of meal-based guidelines and public health messages.

Circadian timing of eating and BMI among adults in the American Time Use Survey

BACKGROUND/OBJECTIVES

Experimental studies of time-restricted eating suggest that limiting the daily eating window, shifting intake to the biological morning, and avoiding eating close to the biological night may promote metabolic health and prevent weight gain.

SUBJECTS/METHODS

We used the Eating & Health Module of the 2006-2008 and 2014-2016 American Time Use Survey to examine cross-sectional associations of timing of eating in relation to sleep/wake times as a proxy for circadian timing with body mass index (BMI). The analytical sample included 38 302 respondents (18-64 years; BMI 18.5-50.0 kg/m²). A single 24-hour time use diary was used to calculate circadian timing of eating variables: eating window (time between first and last eating activity); morning fast (time between end of sleep and start of eating window); and evening fast (time between end of eating window and start of sleep). Multinomial logistic regression and predictive margins were used to estimate adjusted population prevalences (AP) by BMI categories and changes in prevalences associated with a one-hour change in circadian timing of eating, controlling for sociodemographic and temporal characteristics.

RESULTS

A one-hour increase in eating window was associated with lower adjusted prevalence of obesity (AP = 27.1%, SE = 0.1%). Conversely, a one-hour increase in morning fast (AP = 28.7%, SE = 0.1%) and evening fast (AP = 28.5%, SE = 0.1%) were each associated with higher prevalence of obesity; interactions revealed differing patterns of association by combination of eating window with morning/evening fast (p < 0.0001).

CONCLUSIONS

Contrary to hypotheses, longer eating windows were associated with a lower adjusted prevalence of obesity and longer evening fasts were associated with a higher prevalence of obesity. However, as expected, longer morning fast was associated with a higher adjusted prevalence of obesity. Studies are needed to disentangle the contributions of diet quality/quantity and social desirability bias in the relationship between circadian timing of eating and BMI.

Psychometric Testing of a Food Timing Questionnaire and Food Timing Screener

BACKGROUND

Circadian rhythms coordinate multiple biological processes, and time of eating is an important entrainer of peripheral circadian clocks, including those in the gastrointestinal tract and liver. Whereas time of eating can be assessed through valid and reliable tools designed to measure nutrient intake (24-h recalls), currently there is no easily administered, valid, and reliable tool designed to specifically assess both time of food intake and sleep.

OBJECTIVES

The objective of this study was to test the validity and reliability of 2 questionnaires developed to measure food and sleep-wake timing, the Food Timing Questionnaire (FTQ) and Food Timing Screener (FTS), and the agreement between these 2 tools.

METHODS

The content validity of these tools was assessed by an expert panel of 10 registered dietitian nutritionists. Adult volunteers (n = 61) completed both tools to assess internal consistency and test-retest reliability. Criterion-related validity was determined through the association of FTQ and FTS with 2 valid instruments, the Automated Self-Administered 24-hour recall (ASA24®) Dietary Assessment tool and the Munich Chronotype Questionnaire. Agreement between the FTQ and FTS was tested by calculating the Pearson's correlations for both food and sleep-wake timing.

RESULTS

The content validity indexes for both tools were >0.80, and internal consistency and test-retest reliability coefficients were >0.50 for all meals and sleep-wake times. Correlation coefficients were >0.40 between both tools and criterion measures of food intake and sleep except for snacks. Correlations between the FTQ and FTS for all eating events and sleep were >0.60 except for snack 1.

CONCLUSIONS

Both the FTQ and FTS are valid and reliable instruments for meal timing and sleep. However, further psychometric testing in a more expansive and diverse sample will improve the ability of these tools to accurately assess food timing and sleep and their impact on health outcomes.

Differential Effects of One Meal per Day in the Evening on Metabolic Health and Physical Performance in Lean Individuals

Background: Generally, food intake occurs in a three-meal per 24 h fashion with in-between meal snacking. As such, most humans spend more than ∼ 12-16 h per day in the postprandial state. It may be reasoned from an evolutionary point of view, that the human body is physiologically habituated to less frequent meals. Metabolic flexibility (i.e., reciprocal changes in carbohydrate and fatty acid oxidation) is a characteristic of metabolic health and is reduced by semi-continuous feeding. The effects of time-restricted feeding (TRF) on metabolic parameters and physical performance in humans are equivocal. Methods: To investigate the effect of TRF on metabolism and physical performance in free-living healthy lean individuals, we compared the effects of eucaloric feeding provided by a single meal (22/2) vs. three meals per day in a randomized crossover study. We included 13 participants of which 11 (5 males/6 females) completed the study: age 31.0 ± 1.7 years, BMI 24.0 ± 0.6 kg/m² and fat mass (%) 24.0 ± 0.6 (mean ± SEM). Participants consumed all the calories needed for a stable weight in either three meals (breakfast, lunch and dinner) or one meal per day between 17:00 and 19:00 for 11 days per study period. Results: Eucaloric meal reduction to a single meal per day lowered total body mass (3 meals/day -0.5 ± 0.3 vs. 1 meal/day -1.4 ± 0.3 kg, p = 0.03), fat mass (3 meals/day -0.1 ± 0.2 vs. 1 meal/day -0.7 ± 0.2, p = 0.049) and increased exercise fatty acid oxidation (p < 0.001) without impairment of aerobic capacity or strength (p > 0.05). Furthermore, we found lower plasma glucose concentrations during the second half of the day during the one meal per day intervention (p < 0.05). Conclusion: A single meal per day in the evening lowers body weight and adapts metabolic flexibility during exercise via increased fat oxidation whereas physical performance was not affected.

Temporal Eating Patterns and Eating Windows among Adults with Overweight or Obesity

We aim to describe temporal eating patterns in a population of adults with overweight or obesity. In this cross-sectional analysis, data were combined from two separate pilot studies during which participants entered the timing of all eating occasions (>0 kcals) for 10-14 days. Data were aggregated to determine total eating occasions, local time of the first and last eating occasions, eating window, eating midpoint, and within-person variability of eating patterns. Eating patterns were compared between sexes, as well as between weekday and weekends. Participants (n = 85) had a median age of 56 ± 19 years, were mostly female (>70%), white (56.5%), and had a BMI of 31.8 ± 8.0 kg/m². The median eating window was 14 h 04 min [12 h 57 min-15 h 21 min], which was significantly shorter on the weekend compared to weekdays (p < 0.0001). Only 13.1% of participants had an eating window <12 h/d. Additionally, there was greater irregularity with the first eating occasion during the week when compared to the weekend (p = 0.0002). In conclusion, adults with overweight or obesity have prolonged eating windows (>14 h/d). Future trials should examine the contribution of a prolonged eating window on adiposity independent of energy intake.

Effects of Early vs. Late Time-Restricted Eating on Cardiometabolic Health, Inflammation, and Sleep in Overweight and Obese Women: A Study Protocol for the ChronoFast Trial

Background: Time-restricted eating is a promising dietary strategy for weight loss, glucose and lipid metabolism improvements, and overall well-being. However, human studies demonstrated contradictory results for the restriction of food intake to the beginning (early TRE, eTRE) or to the end of the day (late TRE, lTRE) suggesting that more carefully controlled studies are needed.

Objective: The aim of the ChronoFast trial study is to determine whether eTRE or lTRE is a better dietary approach to improve cardiometabolic health upon minimized calorie deficits and nearly stable body weight.

Methods: Here, we present the study protocol of the randomized cross-over ChronoFast clinical trial comparing effects of 2 week eTRE (8:00 to 16:00 h) and lTRE (13:00 to 21:00 h) on insulin sensitivity and other glycemic traits, blood lipids, inflammation, and sleep quality in 30 women with overweight or obesity and increased risk of type 2 diabetes. To ensure timely compliance and unchanged dietary composition, and to minimize possible calorie deficits, real-time monitoring of dietary intake and body weight using a smartphone application, and extensive nutritional counseling are performed. Continuous glucose monitoring, oral glucose tolerance test, 24 h activity tracking, questionnaires, and gene expression analysis in adipose tissue and blood monocytes will be used for assessment of study outcomes.

Discussion: The trial will determine whether eTRE or lTRE is more effective to improve cardiometabolic health, elucidate underlying mechanisms, and contribute to the development of recommendations for medical practice and the wider population.

Clinical Trial Registration:www.ClinicalTrials.gov, Identifier [NCT04351672]

Late Evening Eating Patterns among US Adults Vary in Their Associations With, and Impact on, Energy Intake and Diet Quality: Evidence from What We Eat in America, National Health and Nutrition Examination Survey 2013-2016

BACKGROUND

Evening eating has been associated with higher energy intake and lower nutrient density. However, these qualities may not characterize all late evening (LE) eating patterns.

OBJECTIVE

We sought to characterize US adults' LE eating patterns on a given day and identify differences, if any, in pattern-specific associations with, and impact on, daily energy intake and total diet quality.

DESIGN

LE eating patterns, energy intakes, and Healthy Eating Index (HEI) scores were identified using Day-1 dietary recall data from the cross-sectional National Health and Nutrition Examination Survey 2013-2016.

PARTICIPANTS/SETTING

The sample included adults aged ≥ 20 years (n = 9,861). LE reporters were respondents who consumed foods/beverages between 20:00 and 23:59 on the intake day.

MAIN OUTCOME MEASURES

Energy intake and HEI-2015 scores by LE status/pattern and the impact of LE consumption on these measures.

STATISTICAL ANALYSES

Cluster analysis assigned individuals to LE eating patterns based on the LE energy contribution of food/beverage groups. Regression models estimated energy intake and HEI-2015 scores; estimates were compared between LE reporters and nonreporters. Similarly, LE's contribution to total energy and the difference in total HEI inclusive vs exclusive of LE consumption were estimated and compared among patterns.

RESULTS

Among US adults, 64.4% were LE reporters. Eleven LE patterns were identified; the six most prevalent patterns (representing 89% of LE reporters) were further analyzed. Daily energy intake in all prevalent patterns except the fruit pattern exceeded that of nonreporters by ≥ 268 kcal (unadjusted; P < 0.001), varying by pattern. Conversely, total HEI score did not differ from that of nonreporters (51.0) in any pattern except the fruit pattern, where it was higher (57.4, unadjusted; P < 0.001). Generally, LE consumption's impact on energy was high and its impact on HEI scores was low.

CONCLUSIONS

Late evening food/beverage consumption is common among US adults, and LE patterns are not monolithic in their associations with, and impact on, total energy intake and dietary quality.

Maternal adaptations to food intake across pregnancy: Central and peripheral mechanisms

A sufficient and balanced maternal diet is critical to meet the nutritional demands of the developing fetus and to facilitate deposition of fat reserves for lactation. Multiple adaptations occur to meet these energy requirements, including reductions in energy expenditure and increases in maternal food intake. The central nervous system plays a vital role in the regulation of food intake and energy homeostasis and responds to multiple metabolic and nutrient cues, including those arising from the gastrointestinal tract. This review describes the nutrient requirements of pregnancy and the impact of over- and undernutrition on the risk of pregnancy complications and adult disease in progeny. The central and peripheral regulation of food intake is then discussed, with particular emphasis on the adaptations that occur during pregnancy and the mechanisms that drive these changes, including the possible role of the pregnancy-associated hormones progesterone, estrogen, prolactin, and growth hormone. We identify the need for deeper mechanistic understanding of maternal adaptations, in particular, changes in gut-brain axis satiety signaling. Improved understanding of food intake regulation during pregnancy will provide a basis to inform strategies that prevent maternal under- or overnutrition, improve fetal health, and reduce the long-term health and economic burden for mothers and offspring.

Clock Time of First Eating Episode and Prospective Risk of All-Cause Mortality in US Adults

BACKGROUND

There is increasing recognition that a morning or evening preference is associated with time of eating, metabolic health, and morbidity. However, few studies have examined the association of time of eating with mortality.

OBJECTIVES

To examine the association of time of first recalled ingestive episode with the prospective risk of all-cause mortality.

METHODS

We used mortality-linked data from the NHANES conducted in 1988-1994 and 1999-2014 (n = 34,609; age ≥ 40 years). The exposure was quartiles (Q1-Q4) of clock time of first eating episode self-reported in the baseline 24-hour dietary recall. The outcome was follow-up time from the date of NHANES examination to the date of death or end of the follow-up period (31 December 2015). We used proportional hazards regression methods to determine the independent association of time of first eating episode with relative hazard of all-cause mortality, with adjustments for multiple covariates and the complex survey design. Multiple linear regression methods were used to examine the associations of time of first eating episode with baseline cardiometabolic biomarkers and dietary attributes.

RESULTS

In this national cohort, with a median age of ∼55 years (95% CI: 54.6-55.4 years) at baseline and a median follow-up of 8.3 years (IQR, 8.75 years), there were 10,303 deaths. The median times of first eating episodes in Q1-Q4 were 05:45, 07:00, 08:00, and 10:00, respectively. Covariate-adjusted relative hazards of mortality in Q1 to Q3 of the time of the first eating episode were 0.88 (95% CI: 0.81-0.96), 0.88 (95% CI: 0.81-0.95), 0.94 (95% CI: 0.87-1.02), with Q4 as the referent (P = 0.0008). Qualitative dietary attributes were inversely related with the time of the first eating episode; however, BMI and serum concentrations of glycemic biomarkers increased with later times of first eating episode (P ≤ 0.0001).

CONCLUSIONS

Recall of an earlier time of the first eating episode by ≥40-year-old US participants was suggestive of a small relative survival advantage in this observational study.

Data-driven development of the Meal-based Diet History Questionnaire for Japanese adults

FFQ, the primary method of dietary assessment in large-scale nutritional epidemiological studies, preclude an informed evaluation of the timing of dietary intake and meal-specific dietary intake. In this study, we developed the Meal-based Diet History Questionnaire (MDHQ), a self-administered questionnaire designed for estimating food and nutrient intakes for each meal type separately. The development was done based on a 16-d dietary record obtained from 242 Japanese adults. The MDHQ consisted of the three different parts, with a total of 196 items. Part 1 of the MDHQ asks about consumption frequency of generic food groups (n 24) for each meal type: breakfast, morning snack, lunch, afternoon snack, dinner and night snack. Part 2 of the MDHQ asks about relative consumption frequency of sub-food groups within one of the generic food groups which are asked in Part 1. Combining information derived from Parts 1 and 2 enables us to increase the number of foods we can estimate efficiently but within a limited number of questions. Part 3 of the MDHQ asks about general eating behaviours, which are intended to use in a variety of ways during dietary intake calculation. A series of calculation algorithms for food groups, energy and nutrients was also prepared. Given that the MDHQ was empirically developed based on comprehensive information on actual food consumption, this innovative tool may be promising for future epidemiological research on meal patterns and time of day of dietary intake, or chrono-nutrition research. A rigorous evaluation of validity of the MDHQ is warranted.

Maternal meal irregularities during pregnancy and lifestyle correlates

Meal regularity can influence metabolic health. However, habits of skipping and delaying meals are rarely studied among pregnant women. This study examined the incidence of maternal meal skipping and meal delaying, and their associated lifestyle patterns during pregnancy. Pregnant women in the second trimester (18-24 weeks' gestation; n = 90) were recruited from the antenatal clinics in KK Women's and Children's Hospital, Singapore, 2019-2020. Data on sociodemographic, lifestyle and dietary habits were collected. Firstly, principal component analysis was used to identify lifestyle patterns. Subsequently, multiple logistic regression model was used to examine the association of lifestyle patterns with meal skipping and delaying. In total, 32 (35.6%) women had irregular meals, in which 25 (27.8%) and 26 (28.9%) women reported meal skipping and meal delaying for at least 3 times a week, respectively. Women with 'poor sleep and emotion' pattern as characterized by higher scores for poor sleep, depression, anxiety, and stress symptoms were associated with higher odds of meal skipping (OR 1.99; 95% CI 1.13, 3.53) and meal delaying (2.50; 1.31, 4.79). 'Sedentary' pattern, as characterized by greater daily time spent on television and screen electronic devices, and 'weight and inactivity' pattern, as characterized by higher BMI and physical inactivity level, were not associated with meal regularity. In this study, almost one-third of women reporting meal irregularities during pregnancy. 'Poor sleep and emotion' pattern is associated with a higher incidence of meal skipping and delaying. These findings suggest the need to address sleep and emotional health in interventions promoting healthy nutrition specifically regular eating in pregnancy.

Associations between bedtime eating or drinking, sleep duration and wake after sleep onset: findings from the American time use survey

Sleep hygiene recommendations discourage eating before bedtime; however, the impact of mealtime on sleep has been inconsistent. We examined gender-stratified associations between eating or drinking <1, <2 and <3 h before bedtime, sleep duration and wake after sleep onset (WASO >30 min). This study utilised 2003-2018 data from the American Time Use Survey, a nationally representative sample of USA residents aged ≥15 years. Participants recorded weekday/weekend activities during a 24-h period. Age-specific sleep duration and WASO were estimated categorically and continuously. Eating or drinking were identified from all activities recorded <1, <2 and <3 h before bedtime. Mean ± se sleep duration was 8·0 ± 0·006 h, and 6% of participants ate or drank <1 h prior to weekdays bedtime. Overall, eating or drinking <1 h prior to bedtime was associated with longer weekdays sleep duration. Women and men who ate or drank <1 h before bedtime, v. those who did not, had 35 min (95% CI (30,39)) and 25 min (95 % CI (21,29)) longer sleep duration, respectively, as well as increased odds of WASO; women (OR=2·03, 95% CI (1·66,2·49)) and men (OR=2·64, 95% CI (2·08,3·36)). As the interval of eating or drinking prior to bedtime expanded, odds of short and long sleep durations and WASO decreased. This population-based data linked eating or drinking <1 h before bedtime to longer sleep duration, but increased WASO. Eating or drinking further from bedtime lowers the odds of short and long sleep duration and WASO. Causal pathways are difficult to discern, though inefficient sleep after late-night eating could increase WASO and trigger compensatory increases in sleep duration.

Associations between Fasting Duration, Timing of First and Last Meal, and Cardiometabolic Endpoints in the National Health and Nutrition Examination Survey

Background: Research indicates potential cardiometabolic benefits of energy consumption earlier in the day. This study examined the association between fasting duration, timing of first and last meals, and cardiometabolic endpoints using data from the National Health and Nutrition Examination Survey (NHANES). Methods: Cross-sectional data from NHANES (2005–2016) were utilized. Diet was obtained from one to two 24-h dietary recalls to characterize nighttime fasting duration and timing of first and last meal. Blood samples were obtained for characterization of C-reactive protein (CRP); glycosylated hemoglobin (HbA1c %); insulin; glucose; and high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total cholesterol. Survey design procedures for adjusted linear and logistic regression were performed. Results: Every one-hour increase in nighttime fasting duration was associated with a significantly higher insulin and CRP, and lower HDL. Every one-hour increase in timing of the last meal of the day was statistically significantly associated with higher HbA1c and lower LDL. Every one-hour increase in first mealtime was associated with higher CRP (β = 0.044, p = 0.0106), insulin (β = 0.429, p < 0.01), and glucose (β = 0.662, p < 0.01), and lower HDL (β = −0.377, p < 0.01). Conclusion: In this large public health dataset, evidence for the beneficial effect of starting energy consumption earlier in the day on cardiometabolic endpoints was observed.

Socioeconomic status and lifestyle factors modifies the association between snack foods intake and incidence of metabolic syndrome

BACKGROUND

Intake of snack foods has been previously associated with an elevated risk of chronic disease; however, studies on snack foods and metabolic syndrome (MetS) while considering the modifying effect of socioeconomic status (SES) and lifestyle factors on this association are lacking. We aimed to investigate the association between snack foods intake and the MetS risk, and the mediatory effects of SES and lifestyle factors on the forenamed association among adults who participated in the Tehran Lipid and Glucose Study (2006-2018).

METHODS

This is a prospective study of 1915 participants (male, 40.5%), aged 19-74 year who were free of MetS at baseline. Dietary intakes were gathered using a validated, semi-quantitative food frequency questionnaire at baseline (2006-2008), and with 3-year intervals afterwards. Alternative approach was used for snack foods from all available questionnaires during follow-up. Snack foods were divided into 4 categories, including total snacks, biscuits and cakes, candies and chocolate, and salty snacks. Total snack foods intake and its subgroup (serving/week) were modeled as tertiles. MetS was diagnosed according to the Joint Interim Statement criteria. Physical activity level (PAL) categorized as low/medium and high levels. Information regarding smoking (Smoker/Non-smoker), education (higher/lower education), and occupation (employed/non-employed) was gathered using questionnaire. The Cox regression was used, regarding interaction between snack foods, SES, and PAL on the MetS risk.

RESULTS

A total of 591 incident MetS cases were diagnosed during 8.9 years of follow-up. The median total snack foods intake was 5.2 serving/week (IQR: 3.0-9.1). Total snack foods intake was positively associated with the MetS risk after adjusting for potential confounders (adjusted for age and gender, energy intake, total fiber intake, smoking status, PAL, education levels, family history of diabetes, family history of CVD events, and BMI). After adjustment for confounders, among snacks' subgroups, candies and chocolate intake was positively associated with MetS risk. Moreover, among lower-educated and non-employed participants, candies and chocolate intake was positively associated with the MetS risk, by 38 and 43% respectively. Stratification based on PAL resulted a positive association between intake of total snack foods and candies and chocolates and risk of MetS among participants with low PAL.

CONCLUSION

Snack foods, especially candies and chocolate, increased the risk of MetS, among individuals with a low PAL.

Association between frequency of snacking and all-cause mortality among community-dwelling young-old adults: An age-specific prospective cohort study

AIM

We aimed to clarify whether snacking habits decrease the risk of all-cause mortality in an older Japanese population.

METHODS

The study participants were 64- or 65-year-old community-dwelling residents recruited each survey year from 1996 through 2005. Data on the frequency of snacking and other lifestyle factors were obtained during the baseline survey using self-administered questionnaires, and the participants were followed up annually until the end of 2017. In total, 2943 participants (1484 men and 1459 women) were eligible. All-cause mortality was compared among participants grouped by frequency of snacking (no snacking, one to four times/week, or every day).

RESULTS

The number of deaths recorded over the study period of 43 204 person-years was 357 (24.1%) for men and 173 (11.9%) for women. The mean ± standard deviations for the follow-up period were 14.2 ± 4.9 years in men and 15.2 ± 4.5 years in women. Cox proportional hazard regression analyses showed that after adjusting for potential confounding factors, the hazard ratios for women were 0.64 (95% confidence interval [CI], 0.43-0.94) in the group that had a habit of snacking one to four times/week, and 0.93 (95% CI 0.63-1.36) in the group that had a habit of snacking every day compared with those in the no snacking group. These associations were not observed among men.

CONCLUSIONS

A moderate frequency of snacking slightly decreases the risk of all-cause mortality among women. Our findings might be useful for improving the nutrition statuses in older female adults. Geriatr Gerontol Int 2021; 21: 697-704.