earlier evening meal on weight loss during a weight loss diet: a randomised clinical trial

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.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Risks and Benefits of Intermittent Fasting for the Aging Cardiovascular System

Population aging and the associated increase in cardiovascular disease rates pose serious threats to global public health. Different forms of fasting have become an increasingly attractive strategy to directly address aging and potentially limit or delay the onset of cardiovascular diseases. A growing number of experimental studies and clinical trials indicate that the amount and timing of food intake as well as the daily time window during which food is consumed, are crucial determinants of cardiovascular health. Indeed, intermittent fasting counteracts the molecular hallmarks of cardiovascular aging and promotes different aspects of cardiometabolic health, including blood pressure and glycemic control, as well as body weight reduction. In this report, we summarize current evidence from randomized clinical trials of intermittent fasting on body weight and composition as well as cardiovascular and metabolic risk factors. Moreover, we critically discuss the preventive and therapeutic potential of intermittent fasting, but also possible detrimental effects in the context of cardiovascular aging and related disease. We delve into the physiological mechanisms through which intermittent fasting might improve cardiovascular health, and raise important factors to consider in the design of clinical trials on the efficacy of intermittent fasting to reduce major adverse cardiovascular events among aged individuals at high risk of cardiovascular disease. We conclude that despite growing evidence and interest among the lay and scientific communities in the cardiovascular health-improving effects of intermittent fasting, further research efforts and appropriate caution are warranted before broadly implementing intermittent fasting regimens, especially in elderly persons.

Association of chrononutrition patterns with biological aging: evidence from a nationally representative cross-sectional study

Previous studies mostly focused on the benefits of caloric restriction and fasting on longevity. However, whether the timing and frequency of eating affect aging remains unclear. Here, we investigated the associations between chrononutrition patterns and biological aging, and explored whether and to what extent dietary inflammation mediated this association. 16 531 adults aged 20 to 84 years from the National Health and Nutrition Examination Survey were collected. Chrononutrition patterns were determined with two 24-hour dietary recalls. Phenotypic age was calculated to reflect the biological aging status. The dietary inflammatory index (DII) was used to assess the dietary inflammation. After adjustment of the survey weight and multiple covariates including total energy intake, participants in the third tertile of the time of the first meal (mean 10 : 26) exhibited more advanced biological age (β 0.64; 95% CI, 0.26-1.00) and a higher incidence of accelerated aging (odds ratio (OR) 1.25; 95% CI, 1.06-1.47) compared to those of the first tertile (mean 6 : 14). Higher eating frequency was associated with delayed biological aging in both multivariable linear (β -0.31; 95% CI, -0.44 to -0.19) and logistic regression model (OR 0.90; 95% CI, 0.85-0.95). Furthermore, we found that DII rather than metabolic factors mediated the inverse association between eating frequency and biological aging (mediation proportion 24.67%; 95% CI, 19.83%-32.00%). Our findings demonstrated the association between chrononutrition patterns and biological aging among the US general population and the potential role of dietary inflammation in this association, suggesting that modifying chrononutrition patterns may be a practical and cost-effective strategy for combating aging.

Effect of recommendations of breakfast and late-evening snack habits on body composition and blood pressure: A pilot randomized trial

Breakfast skipping and late-evening snack are prevalent in young adults. This randomized controlled intervention aimed to evaluate the influence of meal habit recommendations on young adults' body composition and blood pressure. Nonpregnant adults (≥20 y old) who were eligible for bioelectrical impedance analysis examination (neither pacemaker installed nor medications that would affect body composition, like diuretics or corticosteroids) were enrolled after they provided informed consent (n = 125). Subjects were randomized into three groups, every group receiving one of the following recommendations: (a) daily breakfast consumption (within 2 h after waking up), (b) avoidance of late-evening snacks (after 21:00h or within 4 h before sleep, with the exception of water), and (c) both recommendations. Body composition and blood pressure were measured before randomization at baseline and at the follow-up 1 y later. Intent-to-treat analysis showed that the recommendation of daily breakfast may contribute to a lower increment of diastolic blood pressure by 3.23 mmHg (95% CI: 0.17-6.28). Receiving the breakfast recommendation was associated with more reduction of total body fat percent by 2.99% (95% CI: 0.23-5.74) and percent trunk fat by 3.63% (95% CI: 0.40-6.86) in inactive youths. Recommendation of avoiding late-evening snack did not significantly affect the outcome measures (ClinicalTrials.gov Identifier: NCT03828812).

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.

Dietary circadian rhythms and cardiovascular disease risk in the prospective NutriNet-Santé cohort

Daily eating/fasting cycles synchronise circadian peripheral clocks, involved in the regulation of the cardiovascular system. However, the associations of daily meal and fasting timing with cardiovascular disease (CVD) incidence remain unclear. We used data from 103,389 adults in the NutriNet-Santé study. Meal timing and number of eating occasions were estimated from repeated 24 h dietary records. We built multivariable Cox proportional-hazards models to examine their association with the risk of CVD, coronary heart disease and cerebrovascular disease. In this study, having a later first meal (later than 9AM compared to earlier than 8AM) and last meal of the day (later than 9PM compared to earlier than 8PM) was associated with a higher risk of cardiovascular outcomes, especially among women. Our results suggest a potential benefit of adopting earlier eating timing patterns, and coupling a longer nighttime fasting period with an early last meal, rather than breakfast skipping, in CVD prevention.

Associations of meal timing, number of eating occasions and night-time fasting duration with incidence of type 2 diabetes in the NutriNet-Santé cohort

BACKGROUND

Food intake plays a pivotal role in regulating circadian rhythms, which modulate glucose and lipid homeostasis. However, studies investigating the association of meal timing and type 2 diabetes (T2D) incidence are lacking. The objective of this study was to investigate the longitudinal associations of meal timing, number of eating occasions and night-time fasting duration with incidence of T2D.

METHODS

In total, 103 312 adults [79% women, mean age at baseline = 42.7 (SD = 14.6)] from the NutriNet-Santé cohort (2009-21) were included. Participants' meal timings and frequency were assessed using repeated 24-h dietary records and averaged from the first 2 years of follow-up (5.7 records/participant). Associations of meal timing, number of eating occasions and night-time fasting duration with incidence of T2D were assessed by using multivariable Cox proportional hazard models adjusted for known risk factors.

RESULTS

During a median follow-up of 7.3 years, 963 new cases of T2D were ascertained. Compared with participants habitually having a first meal before 8AM, those eating after 9AM had a higher incidence of T2D (HR = 1.59, 95% CI 1.30-1.94). Time of last meal was not associated with T2D incidence. Each additional eating episode was associated with a lower incidence of T2D (HR = 0.95, 95% CI 0.90-0.99). Night-time fasting duration was not associated with T2D incidence, except in participants having breakfast before 8AM and fasting for >13 h overnight (HR = 0.47, 95% CI 0.27-0.82).

CONCLUSIONS

In this large prospective study, a later first meal was associated with a higher incidence of T2D. If confirmed in other large-scale studies, an early breakfast should be considered in preventing T2D.

Associations of timing of food intake with energy intake, eating behaviour traits and psychosocial factors in adults with overweight and obesity

Introduction

Whether a late distribution of food intake impacts obesity through increased energy intake remains uncertain and the behavioural characterization of late eating needs to be further investigated. The first objective of this study was to assess the associations between late eating and body mass index (BMI) and total energy intake (TEI), and whether TEI mediates the association between late eating and BMI. The second objective was to assess the associations between late eating and eating behaviour traits or psychosocial factors and whether eating behaviour traits mediate the association between late eating and TEI.

Methods

Baseline data from 301 individuals (56% women, age = 38.7 ± 8.5 years; BMI = 33.2 ± 3.4 kg/m²), who participated in four weight loss studies were used in this cross-sectional study. Total energy intake was assessed using a three-day food record from which the percentage of TEI after 17:00 and after 20:00 was calculated. Eating behaviour traits and psychosocial factors were assessed with questionnaires. Pearson correlations and mediation analyses adjusted for age, sex, underreporting of energy intake, sleep duration and bedtime were performed.

Results

Percent TEI after 17:00 and after 20:00 were associated with TEI (r = 0.13, p = 0.03 for both), and TEI mediated the association between percent TEI after 17:00 and BMI (β = 0.01 ± 0.01, 95% CI: 0.001, 0.02). Percent TEI after 17:00 was associated with disinhibition (r = 0.13, p = 0.03) and percent TEI after 20:00 was associated with susceptibility to hunger (r = 0.13, p = 0.03), stress (r = 0.24, p = 0.002) and anxiety (r = 0.28, p = 0.0004). In women, disinhibition mediated the association between percent TEI after 17:00 and TEI (β = 3.41 ± 1.43, 95% CI: 0.92, 6.47). Susceptibility to hunger mediated the association between percent TEI after 20:00 and TEI (β = 0.96 ± 0.59, 95% CI: 0.02, 2.34) in men and women.

Conclusion

Late eating is associated with TEI and suboptimal eating behaviours which could contribute to explaining the association between timing of food intake and obesity.

Association of meal timing with body composition and cardiometabolic risk factors in young adults

PURPOSE

To investigate the association of meal timing with body composition and cardiometabolic risk factors in young adults.

METHODS

In this cross-sectional study participated 118 young adults (82 women; 22 ± 2 years old; BMI: 25.1 ± 4.6 kg/m²). Meal timing was determined via three non-consecutive 24-h dietary recalls. Sleep outcomes were objectively assessed using accelerometry. The eating window (time between first and last caloric intake), caloric midpoint (local time at which ≥ 50% of daily calories are consumed), eating jetlag (variability of the eating midpoint between non-working and working days), time from the midsleep point to first food intake, and time from last food intake to midsleep point were calculated. Body composition was determined by DXA. Blood pressure and fasting cardiometabolic risk factors (i.e., triglycerides, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and insulin resistance) were measured.

RESULTS

Meal timing was not associated with body composition (p > 0.05). The eating window was negatively related to HOMA-IR and cardiometabolic risk score in men (R² = 0.348, β = - 0.605; R² = 0.234, β = - 0.508; all p ≤ 0.003). The time from midsleep point to first food intake was positively related to HOMA-IR and cardiometabolic risk score in men (R² = 0.212, β = 0.485; R² = 0.228, β = 0.502; all p = 0.003). These associations remained after adjusting for confounders and multiplicity (all p ≤ 0.011).

CONCLUSIONS

Meal timing seems unrelated to body composition in young adults. However, a longer daily eating window and a shorter time from midsleep point to first food intake (i.e., earlier first food intake in a 24 h cycle) are associated with better cardiometabolic health in young men.

CLINICAL TRIAL REGISTRATION

NCT02365129 ( https://www.

CLINICALTRIALS

gov/ct2/show/NCT02365129?term=ACTIBATE&draw=2&rank=1 ).

A hypothetical intervention of the timing of dietary intake on weight and body composition after initial weight loss

OBJECTIVE

This study estimated the effect of hypothetical interventions of higher and lower frequency of breakfast and post-dinner snack consumption (breakfast consumption 0-4 vs. 5-7 times/week and post-dinner snack consumption 0-2 vs. 3-7 times/week) on changes in body weight and composition over 18 months after a successful 6-month standard behavioral weight-loss program.

METHODS

The study analyzed data from the Innovative Approaches to Diet, Exercise and Activity (IDEA) study.

RESULTS

If all participants consumed a breakfast meal 5 to 7 times/week over 18 months, they would have regained 2.95 kg of body weight on average (95% CI: 2.01 to 3.96), which is 0.59 kg (95% CI: -0.86 to -0.32) lower than if all participants consumed breakfast 0 to 4 times/week. If all participants consumed a post-dinner snack 0 to 2 times/week, they would have regained 2.86 kg of body weight on average (95% CI: 0.99 to 5.25), which is 0.83 kg (95% CI: -1.06 to -0.59) lower than if all consumed a post-dinner snack 3 to 7 times/week.

CONCLUSIONS

Regular breakfast consumption and minimizing post-dinner snacking may modestly mitigate weight and body fat regain over 18 months after initial weight loss.

Eating Patterns of Young Women (18–25 y) with Overweight and Obesity: A Preliminary Investigation

Overweight and obesity impact up to 40% of young women in Australia; however, young women are challenging to recruit to research and are rarely the focus of weight loss interventions. This study aimed to examine dietary patterns in young women (18–25 years; BMI > 25 kg/m2). An analysis of participants’ (mean age: 22.6 year; BMI: 32.2 kg/m2) 3-day food records found young women with overweight/obesity consumed a diet characterised by total energy intake of 9174 (2526) kJ/day, with the first meal at 9:12 am (range: 4:30 am–12:40 pm), the last at 10:43 pm (range: 2:40 pm–2:00 am), and an average eating window of 11.5 h. Young women had poor quality diets, which did not meet dietary recommendations for most core food groups, and high intake of refined carbohydrates. They also reported consuming at least one takeaway meal per day and >30% of total energy intake was from discretionary items. The findings showed that young women with overweight or obesity consume most of their energy intake in the afternoons and late into the evenings and have poor-quality diets with high-discretionary intake, each of which have been shown in previous work to be associated with increased weight and risk of metabolic comorbidities. While these findings require further examination in larger groups with both qualitative and longitudinal data collection to verify the impact of these eating patterns on weight maintenance, the eating behaviours identified here may present a suitable target for novel weight loss interventions in young women, who are an understudied population group in need of tailored weight management solutions.

Distribution of energy intake across the day and weight loss: A systematic review and meta-analysis

Consuming a greater proportion of total energy intake earlier in the day rather than in the evening is proposed to positively influence weight loss and health, potentially due to greater synchronization of human body circadian rhythms. This systematic review provides an update on existing evidence regarding earlier distributed eating patterns in weight loss interventions. Using a robust search strategy in five electronic databases, nine randomized controlled trials investigating the impact of energy intake distribution on weight loss were identified. Following critical appraisal, a random-effects meta-analyses found that, in the context of an energy-reduced diet, distributing energy intake with a focus on earlier intake resulted in significantly greater weight loss (-1.23 kg; 95% CI 2.40, -0.06, p = 0.04). Improvements in HOMA-IR, fasting glucose, and LDL cholesterol were also seen. The current study provides a timely update on the evidence linking distribution of total daily energy intake and health, showing that a focus on earlier intakes can result in greater short-term weight loss compared with later intakes. Future studies are needed to elucidate the impact that earlier intakes may have on weight management and metabolic health.

Impact of early time-restricted eating on diet quality, meal frequency, appetite, and eating behaviors: A randomized trial

OBJECTIVE

Time-restricted eating (TRE) can reduce body weight, but it is unclear how it influences dietary patterns and behavior. Therefore, this study assessed the effects of TRE on diet quality, appetite, and several eating behaviors.

METHODS

Adults with obesity were randomized to early TRE plus energy restriction (eTRE + ER; 8-hour eating window from 7:00 a.m. to 3:00 p.m.) or a control eating schedule plus energy restriction (CON + ER; ≥12-hour window) for 14 weeks. Food intake was assessed via the Remote Food Photography Method, while eating patterns, appetite, and eating behaviors were assessed via questionnaires.

RESULTS

A total of 59 participants completed the trial, of whom 45 had valid food records. eTRE + ER did not affect eating frequency, eating restraint, emotional eating, or the consistency of mealtimes relative to CON + ER. eTRE + ER also did not affect overall diet quality. The intensity and frequency of hunger and fullness were similar between groups, although the eTRE + ER group was hungrier while fasting.

CONCLUSIONS

When combined with a weight-loss program, eTRE does not affect diet quality, meal frequency, eating restraint, emotional eating, or other eating behaviors relative to eating over more than a 12-hour window. Rather, participants implement eTRE as a simple timing rule by condensing their normal eating patterns into a smaller eating window.

Time of Dietary Energy and Nutrient Intake and Body Mass Index in Children: Compositional Data Analysis from the Childhood Obesity Project (CHOP) Trial

Meal timing is suggested to influence the obesity risk in children. Our aim was to analyse the effect of energy and nutrient distributions at eating occasions (EO), including breakfast, lunch, supper, and snacks, on the BMI z-score (zBMI) during childhood in 729 healthy children. BMI and three-day dietary protocols were obtained at 3, 4, 5, 6, and 8 years of age, and dietary data were analysed as the percentage of the mean total energy intake (TEI; %E). Intakes at EOs were transformed via an isometric log-ratio transformation and added as exposure variables to linear mixed-effects models. Stratified analyses by country and recategorization of EOs by adding intake from snacks to respective meals for further analyses were performed. The exclusion of subjects with less than three observations and the exclusion of subjects who skipped one EO or consumed 5% energy or less at one EO were examined in sensitivity analyses. Around 23% of the children were overweight at a given time point. Overweight and normal-weight children showed different distributions of dietary intakes over the day; overweight children consumed higher intakes at lunch and lower intakes of snacks. However, no significant effects of timing of EOs on zBMI were found in regression analyses.

Effectiveness of Early Time-Restricted Eating for Weight Loss, Fat Loss, and Cardiometabolic Health in Adults With Obesity: A Randomized Clinical Trial

Importance

It is unclear how effective intermittent fasting is for losing weight and body fat, and the effects may depend on the timing of the eating window. This randomized trial compared time-restricted eating (TRE) with eating over a period of 12 or more hours while matching weight-loss counseling across groups.

Objective

To determine whether practicing TRE by eating early in the day (eTRE) is more effective for weight loss, fat loss, and cardiometabolic health than eating over a period of 12 or more hours.

Design, Setting, and Participants

The study was a 14-week, parallel-arm, randomized clinical trial conducted between August 2018 and April 2020. Participants were adults aged 25 to 75 years with obesity and who received weight-loss treatment through the Weight Loss Medicine Clinic at the University of Alabama at Birmingham Hospital.

Interventions

All participants received weight-loss treatment (energy restriction [ER]) and were randomized to eTRE plus ER (8-hour eating window from 7:00 to 15:00) or control eating (CON) plus ER (≥12-hour window).

Main Outcomes and Measures

The co-primary outcomes were weight loss and fat loss. Secondary outcomes included blood pressure, heart rate, glucose levels, insulin levels, and plasma lipid levels.

Results

Ninety participants were enrolled (mean [SD] body mass index, 39.6 [6.7]; age, 43 [11] years; 72 [80%] female). The eTRE+ER group adhered 6.0 (0.8) days per week. The eTRE+ER intervention was more effective for losing weight (-2.3 kg; 95% CI, -3.7 to -0.9 kg; P = .002) but did not affect body fat (-1.4 kg; 95% CI, -2.9 to 0.2 kg; P = .09) or the ratio of fat loss to weight loss (-4.2%; 95% CI, -14.9 to 6.5%; P = .43). The effects of eTRE+ER were equivalent to reducing calorie intake by an additional 214 kcal/d. The eTRE+ER intervention also improved diastolic blood pressure (-4 mm Hg; 95% CI, -8 to 0 mm Hg; P = .04) and mood disturbances, including fatigue-inertia, vigor-activity, and depression-dejection. All other cardiometabolic risk factors, food intake, physical activity, and sleep outcomes were similar between groups. In a secondary analysis of 59 completers, eTRE+ER was also more effective for losing body fat and trunk fat than CON+ER.

Conclusions and Relevance

In this randomized clinical trial, eTRE was more effective for losing weight and improving diastolic blood pressure and mood than eating over a window of 12 or more hours at 14 weeks.

Trial Registration

ClinicalTrials.gov Identifier: NCT03459703.

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.

Carbohydrate intake and circadian synchronicity in the regulation of glucose homeostasis

PURPOSE OF REVIEW

Glucose metabolism is under circadian regulation, with insulin secretion and sensitivity being highest in the morning as compared to the evening. The present review will discuss the existing evidence for the role of meal and macronutrient timing to improve glucose metabolism and reset circadian clocks, with a focus on the evidence in humans.

RECENT FINDINGS

Shortening the daily eating window (also known as time-restricted eating), or skewing food intake towards breakfast and away from the evening meal both improve glucose control in people with impaired glucose metabolism. Insulin is recently purported to be a zeitgeber and thus an important reset signal for peripheral circadian clocks in vitro and in mice. Although few studies have tested the impact of macronutrient timing in humans, eating a greater proportion of carbohydrates earlier, rather than later, in the day is associated with better glucose control.

SUMMARY

The impact of carbohydrate intake timing on endogenous central and peripheral clocks, and its potential to optimize circadian regulation and improve glycaemic control, are not well understood but are currently under intense exploration.