A randomized controlled trial to compare the effects of time-restricted eating versus Mediterranean diet on symptoms and quality of life in bipolar disorder.

BACKGROUND: The primary objective of this randomized controlled trial (RCT) is to establish the effectiveness of time-restricted eating (TRE) compared with the Mediterranean diet for people with bipolar disorder (BD) who have symptoms of sleep disorders or circadian rhythm sleep-wake disruption. This work builds on the growing evidence that TRE has benefits for improving circadian rhythms. TRE and Mediterranean diet guidance will be offered remotely using self-help materials and an app, with coaching support. METHODS: This study is an international RCT to compare the effectiveness of TRE and the Mediterranean diet. Three hundred participants will be recruited primarily via social media. Main inclusion criteria are: receiving treatment for a diagnosis of BD I or II (confirmed via DIAMOND structured diagnostic interview), endorsement of sleep or circadian problems, self-reported eating window of ≥ 12 h, and no current mood episode, acute suicidality, eating disorder, psychosis, alcohol or substance use disorder, or other health conditions that would interfere with or limit the safety of following the dietary guidance. Participants will be asked to complete baseline daily food logging for two weeks and then will be randomly allocated to follow TRE or the Mediterranean diet for 8 weeks, during which time, they will continue to complete daily food logging. Intervention content will be delivered via an app. Symptom severity interviews will be conducted at baseline; mid-intervention (4 weeks after the intervention begins); end of intervention; and at 6, 9, and 15 months post-baseline by phone or videoconference. Self-rated symptom severity and quality of life data will be gathered at those timepoints, as well as at 16 weeks post baseline. To provide a more refined index of whether TRE successfully decreases emotional lability and improves sleep, participants will be asked to complete a sleep diary (core CSD) each morning and complete six mood assessments per day for eight days at baseline and again at mid-intervention. DISCUSSION: The planned research will provide novel and important information on whether TRE is more beneficial than the Mediterranean diet for reducing mood symptoms and improving quality of life in individuals with BD who also experience sleep or circadian problems. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT06188754.

Diet and Meal Pattern Determinants of Glucose Levels and Variability in Adults with and without Prediabetes or Early-Onset Type 2 Diabetes: A Pilot Study.

This observational pilot study examined the association between diet, meal pattern and glucose over a 2-week period under free-living conditions in 26 adults with dysglycemia (D-GLYC) and 14 with normoglycemia (N-GLYC). We hypothesized that a prolonged eating window and late eating occasions (EOs), along with a higher dietary carbohydrate intake, would result in higher glucose levels and glucose variability (GV). General linear models were run with meal timing with time-stamped photographs in real time, and diet composition by dietary recalls, and their variability (SD), as predictors and glucose variables (mean glucose, mean amplitude of glucose excursions [MAGE], largest amplitude of glucose excursions [LAGE] and GV) as dependent variables. After adjusting for calories and nutrients, a later eating midpoint predicted a lower GV (ß = -2.3, SE = 1.0, p = 0.03) in D-GLYC, while a later last EO predicted a higher GV (ß = 1.5, SE = 0.6, p = 0.04) in N-GLYC. A higher carbohydrate intake predicted a higher MAGE (ß = 0.9, SE = 0.4, p = 0.02) and GV (ß = 0.4, SE = 0.2, p = 0.04) in N-GLYC, but not D-GLYC. In summary, our data suggest that meal patterns interact with dietary composition and should be evaluated as potential modifiable determinants of glucose in adults with and without dysglycemia. Future research should evaluate causality with controlled diets.

Neuroendocrine effects of the duper mutation in Syrian hamsters: a role for Cryptochrome 1.

Molecular and physiological determinants of the timing of reproductive events, including the pre-ovulatory LH surge and seasonal fluctuations in fertility, are incompletely understood. We used the Cryptochrome 1-deficient duper mutant to examine the role of this core circadian clock gene in Syrian hamsters. We find that the phase of the LH surge and its stability upon shifts of the light: dark cycle are altered in duper mutants. The intensity of immunoreactive PER1 in GnRH cells of the preoptic area peaks earlier in the day in duper than wild type hamsters. We note that GnRH fibers coursing through the suprachiasmatic nucleus (SCN) contact vasopressin- and VIP-immunoreactive cells, suggesting a possible locus of circadian control of the LH surge. Unlike wild types, duper hamsters do not regress their gonads within 8 weeks of constant darkness, despite evidence of melatonin secretion during the subjective night. In light of the finding that the duper allele is a stop codon in Cryptochrome 1, our results suggest important neuroendocrine functions of this core circadian clock gene.

Time-restricted eating did not alter insulin sensitivity or ß-cell function in adults with obesity: A randomized pilot study.

OBJECTIVE: Decreased insulin sensitivity and impairment of ß-cell function predate and predict development of type 2 diabetes mellitus. Time-restricted eating (TRE) might have a benefit for these parameters. The objective of this pilot study was to investigate this possibility. METHODS: Secondary analysis of a randomized controlled trial comparing 12 weeks of TRE (8-hour eating window) to unrestricted eating (non-TRE) was performed. Participants were adults with overweight or obesity and without diabetes. Two-hour oral glucose tolerance testing was performed at baseline and end-intervention. Glucose tolerance test-derived measures of insulin sensitivity, insulin secretion, and ß-cell function were compared between groups. RESULTS: Participants (17 women/3 men with mean [SD] age 45.5 [12.1] years and BMI 34.1 [7.5] kg/m2 ) with a prolonged eating window (15.4 [0.9] hours) were randomized to TRE (n = 11) or non-TRE (n = 9). The quantitative insulin sensitivity check index (QUICKI), Stumvoll index, Avignon index, insulinogenic index, insulin area under the curve/glucose area under the curve, and oral disposition index did not differ between the TRE and non-TRE groups at end-intervention. CONCLUSIONS: In adults with overweight or obesity and without diabetes, TRE did not significantly alter insulin sensitivity, insulin secretion, or ß-cell function over a 12-week intervention. Whether TRE is beneficial in adults with prediabetes or type 2 diabetes mellitus warrants further investigation.

Predicting energy intake with an accelerometer-based intake-balance method.

Nutritional interventions often rely on subjective assessments of energy intake (EI), but these are susceptible to measurement error. To introduce an accelerometer-based intake-balance method for assessing EI using data from a time-restricted eating (TRE) trial. Nineteen participants with overweight/obesity (25-63 years old; 16 females) completed a 12-week intervention (NCT03129581) in a control group (unrestricted feeding; n 8) or TRE group (n 11). At the start and end of the intervention, body composition was assessed by dual-energy X-ray absorptiometry (DXA) and daily energy expenditure (EE) was assessed for 2 weeks via wrist-worn accelerometer. EI was back-calculated as the sum of net energy storage (from DXA) and EE (from accelerometer). Accelerometer-derived EI estimates were compared against estimates from the body weight planner of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Mean EI for the control group declined by 138 and 435 kJ/day for the accelerometer and NIDDK methods, respectively (both P ≥ 0·38), v. 1255 and 1469 kJ/day, respectively, for the TRE group (both P < 0·01). At follow-up, the accelerometer and NIDDK methods showed excellent group-level agreement (mean bias of -297 kJ/day across arms; standard error of estimate 1054 kJ/day) but high variability at the individual level (limits of agreement from -2414 to +1824 kJ/day). The accelerometer-based intake-balance method showed plausible sensitivity to change, and EI estimates were biologically and behaviourally plausible. The method may be a viable alternative to self-report EI measures. Future studies should assess criterion validity using doubly labelled water.

The effects of time-restricted eating and weight loss on bone metabolism and health: a 6-month randomized controlled trial.

OBJECTIVE: This study explored the impact of time-restricted eating (TRE) versus standard dietary advice (SDA) on bone health. METHODS: Adults with ≥1 component of metabolic syndrome were randomized to TRE (ad libitum eating within 12 hours) or SDA (food pyramid brochure). Bone turnover markers and bone mineral content/density by dual energy x-ray absorptiometry were assessed at baseline and 6-month follow-up. Statistical analyses were performed in the total population and by weight loss response. RESULTS: In the total population (n = 42, 76% women, median age 47 years [IQR: 31-52]), there were no between-group differences (TRE vs. SDA) in any bone parameter. Among weight loss responders (≥0.6 kg weight loss), the bone resorption marker ß-carboxyterminal telopeptide of type I collagen tended to decrease after TRE but increase after SDA (between-group differences p = 0.041), whereas changes in the bone formation marker procollagen type I N-propeptide did not differ between groups. Total body bone mineral content decreased after SDA (p = 0.028) but remained unchanged after TRE (p = 0.31) in weight loss responders (between-group differences p = 0.028). Among nonresponders (<0.6 kg weight loss), there were no between-group differences in bone outcomes. CONCLUSIONS: TRE had no detrimental impact on bone health, whereas, when weight loss occurred, it was associated with some bone-sparing effects compared with SDA.

Time-restricted eating alters the 24-hour profile of adipose tissue transcriptome in men with obesity.

OBJECTIVE: Time-restricted eating (TRE) restores circadian rhythms in mice, but the evidence to support this in humans is limited. The objective of this study was to investigate the effects of TRE on 24-hour profiles of plasma metabolites, glucoregulatory hormones, and the subcutaneous adipose tissue (SAT) transcriptome in humans. METHODS: Men (n = 15, age = 63 [4] years, BMI 30.5 [2.4] kg/m2 ) were recruited. A 35-hour metabolic ward stay was conducted at baseline and after 8 weeks of 10-hour TRE. Assessment included 24-hour profiles of plasma glucose, nonesterified fatty acid (NEFA), triglyceride, glucoregulatory hormones, and the SAT transcriptome. Dim light melatonin onset and cortisol area under the curve were calculated. RESULTS: TRE did not alter dim light melatonin onset but reduced morning cortisol area under the curve. TRE altered 24-hour profiles of insulin, NEFA, triglyceride, and glucose-dependent insulinotropic peptide and increased transcripts of circadian locomotor output cycles protein kaput (CLOCK) and nuclear receptor subfamily 1 group D member 2 (NR1D2) and decreased period circadian regulator 1 (PER1) and nuclear receptor subfamily 1 group D member 1 (NR1D1) at 12:00 am. The rhythmicity of 450 genes was altered by TRE, which enriched in transcripts for transcription corepressor activity, DNA-binding transcription factor binding, regulation of chromatin organization, and small GTPase binding pathways. Weighted gene coexpression network analysis revealed eigengenes that were correlated with BMI, insulin, and NEFA. CONCLUSIONS: TRE restored 24-hour profiles in hormones, metabolites, and genes controlling transcriptional regulation in SAT, which could underpin its metabolic health benefit.

The impact of a self-selected time restricted eating intervention on eating patterns, sleep, and late-night eating in individuals with obesity.

Background: Time restricted eating (TRE), limiting eating to a specific daily window, is a novel dietary intervention, but the mechanisms by which TRE results in weight loss remain unclear. The goal of the current study was to examine changes in eating patterns, sleep, and late-night eating, and associations with health outcomes in a secondary analysis of a 12-week self-selected TRE intervention. Methods: Twenty participants 18-65 years with BMI ≥25 kg/m2 completed the 12-week trial. Participants randomized to TRE (n = 11) were instructed to eat during a self-selected 8-h window, while the non-TRE group (n = 9) followed their typical eating habits. All participants logged oral intake using the myCircadian Clock mobile application throughout the entire intervention. Anthropometrics, HbA1c, an oral glucose tolerance test, and 2 weeks of actigraphy monitoring were completed at pre-intervention and end-intervention. Independent samples t-tests compared differences between groups. Data are presented as mean ± standard deviation. Results: At preintervention, late night eating was significantly associated with higher fasting glucose (r = 0.59, p = 0.006) and higher HbA1c (r = 0.46, p = 0.016). The TRE group significantly delayed the timing of the first eating occasion by 2.72 ± 1.48 h relative to wake time (p < 0.001) and advanced the timing of the last eating occasion by 1.25 ± 0.8 h relative to bedtime (p < 0.001). The non-TRE group, on average, maintained their eating pattern. Sleep measures did not change from pre- to end-intervention, however greater restriction of the eating window was associated with longer sleep duration at end-intervention (ß = -0.46 [95% CI -9.2, -0.4], p = 0.03). The TRE group significantly reduced the prevalence of late night eating (eating within 2 h of bedtime) by 14 ± 6% (p = 0.028) with 63% of participants completely eliminating late night eating at end-intervention. Conclusion: A self-selected TRE intervention significantly shifted meal timing, reduced late-night eating while prolonging sleep duration. Trial registry: ClinicalTrials.gov, identifier: 03129581.

Feasibility of time-restricted eating and impacts on cardiometabolic health in 24-h shift workers: The Healthy Heroes randomized control trial.

Over a quarter of the workforce in industrialized countries does shift work, which increases the risk for cardiometabolic disease. Yet shift workers are often excluded from lifestyle intervention studies to reduce this risk. In a randomized control trial with 137 firefighters who work 24-h shifts (23-59 years old, 9% female), 12 weeks of 10-h time-restricted eating (TRE) was feasible, with TRE participants decreasing their eating window (baseline, mean 14.13 h, 95% CI 13.78-14.47 h; intervention, 11.13 h, 95% CI 10.73-11.54 h, p = 3.29E-17) with no adverse effects, and improved quality of life assessed via SF-36 (ClinicalTrials.gov: NCT03533023). Compared to the standard of care (SOC) arm, TRE significantly decreased VLDL particle size. In participants with elevated cardiometabolic risks at baseline, there were significant reductions in TRE compared to SOC in glycated hemoglobin A1C and diastolic blood pressure. For individuals working a 24-h shift schedule, TRE is feasible and can improve cardiometabolic health, especially for individuals with increased risk. VIDEO ABSTRACT.

Time-restricted eating to improve cardiometabolic health: The New York Time-Restricted EATing randomized clinical trial - Protocol overview.

Re-aligning eating patterns with biological rhythm can reduce the burden of metabolic syndrome in older adults with overweight or obesity. Time-restricted eating (TRE) has been shown to result in weight loss and improved cardiometabolic health while being less challenging than counting calories. The New York Time-Restricted EATing study (NY-TREAT) is a two-arm, randomized clinical trial (RCT) that aims to examine the efficacy and sustainability of TRE (eating window ≤10 h/day) vs. a habitual prolonged eating window (HABIT, ≥14 h/day) in metabolically unhealthy midlife adults (50-75 years) with overweight or obesity and prediabetes or type 2 diabetes (T2D). Our primary hypothesis is that the TRE will result in greater weight loss compared to HABIT at 3 months. The efficacy of the TRE intervention on body weight, fat mass, energy expenditure, and glucose is tested at 3 months, and the sustainability of its effect is measured at 12 months, with ambulatory assessments of sleep and physical activity (ActiGraph), eating pattern (smartphone application), and interstitial glucose (continuous glucose monitoring). The RCT also includes state-of-the-art measurements of body fat (quantitative magnetic resonance), total energy expenditure (doubly-labelled water), insulin secretion, insulin resistance, and glucose tolerance. Adherence to self-monitoring and reduced eating window are monitored remotely in real-time. This RCT will provide further insight into the effects of TRE on cardiometabolic health in individuals with high metabolic risk. Sixty-two participants will be enrolled, and with estimated 30% attrition, 42 participants will return at 12 months. This protocol describes the design, interventions, methods, and expected outcomes. Clinical trial registration:NCT04465721 IRB: AAAS7791.

The duper mutation reveals previously unsuspected functions of Cryptochrome 1 in circadian entrainment and heart disease.

The Cryptochrome 1 (Cry1)-deficient duper mutant hamster has a short free-running period in constant darkness (τDD) and shows large phase shifts in response to brief light pulses. We tested whether this measure of the lability of the circadian phase is a general characteristic of Cry1-null animals and whether it indicates resistance to jet lag. Upon advance of the light:dark (LD) cycle, both duper hamsters and Cry1-/- mice re-entrained locomotor rhythms three times as fast as wild types. However, accelerated re-entrainment was dissociated from the amplified phase-response curve (PRC): unlike duper hamsters, Cry1-/- mice show no amplification of the phase response to 15' light pulses. Neither the amplified acute shifts nor the increased rate of re-entrainment in duper mutants is due to acceleration of the circadian clock: when mutants drank heavy water to lengthen the period, these aspects of the phenotype persisted. In light of the health consequences of circadian misalignment, we examined effects of duper and phase shifts on a hamster model of heart disease previously shown to be aggravated by repeated phase shifts. The mutation shortened the lifespan of cardiomyopathic hamsters relative to wild types, but this effect was eliminated when mutants experienced 8-h phase shifts every second week, to which they rapidly re-entrained. Our results reveal previously unsuspected roles of Cry1 in phase shifting and longevity in the face of heart disease. The duper mutant offers new opportunities to understand the basis of circadian disruption and jet lag.

Associations between the timing of eating and weight-loss in calorically restricted healthy adults: Findings from the CALERIE study.

Calorie restriction (CR) and time-restricted eating (TRE) are distinctly different dietary management strategies with overlapping health outcomes. After two years of CR, healthy participants in the Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy (CALERIE) study showed significant weight-loss relative to the ad libitum intake control group and achieved 12% CR on average. Preclinical rodent studies have shown that sustaining a consistent eating interval of 8-12 h between the first and last calories of each day-without reducing daily calorie intake-can impart health benefits that partly overlap with those imparted by CR. Preclinical CR protocols often inadvertently restrict eating interval, and conversely, clinical studies of TRE often inadvertently result in modest CR. Other factors related to daily timing of food intake, such as breakfast skipping, and early food intake also impact health outcomes. These observations have raised the possibility that CR protocols can be further optimized by adopting relevant aspects of eating patterns to boost weight loss and health outcomes. With a goal to inform CR protocols that aim to optimize eating patterns, the objective of this secondary analysis was to test aspects of daily timing of food intake associated with greater weight loss in the CALERIE study participants. We found no difference in the daily time window of energy intake between the CR and control arms. In the CALERIE trial, weight change was used as a proxy for adherence to CR, and hence we used linear models to test the relationships among CR, weight loss, and temporal aspects of daily eating pattern. We found that CR alone could explain 41% of the variance in weight loss. We tested the contribution of eating interval, time to 50% daily calorie intake, and day-to-day shifts in the time of the first (breakfast) or last meal consumed. We found that eating interval and variation in the timing of the first and last meals significantly influenced weight loss after controlling for CR. Our models suggest that shorter eating intervals are associated with greater CR (1% of the variance explained) and facilitate additional weight loss. Our models suggest that less day to day variation in first mealtime is directly associated with weight loss (6% of the variance explained). More regular first meal timing is also associated with greater CR (2% of the variance explained). Likewise, regular timing of the last daily meal is directly associated with weight loss (1% of the variance explained) and greater CR (1% of the variance explained). The time to 50% of daily calorie intake or consuming half the caloric intake earlier in the day is associated with additional CR (2% of the variance explained). In summary, these secondary analyses on CALERIE data suggest that - in order to maximize CR and weight loss - future CR protocols should encourage participants to adopt consistent timing of their first and last meals, a shorter eating window, and earlier consumption of food.

Time-restricted eating improves glycemic control and dampens energy-consuming pathways in human adipose tissue.

OBJECTIVE: We sought to examine the effects of 8 wk of time-restricted eating (TRE) on glucose metabolism and the adipose tissue transcriptome during a metabolic ward stay in men with obesity. METHODS: In a single-arm, pre-post trial, 15 men (ages 63 ± 4 y, body mass index = 30.5 ± 2.4 kg/m2, waist circumference = 113 ± 4 cm) with obesity but no history of diabetes were enrolled and underwent 2 wk of baseline monitoring before they were instructed to eat their regular diets within a contiguous 10-h time frame each day for 8 wk. Metabolic testing was performed at baseline and week 8 during a 35-h metabolic ward stay, during which all food intake was strictly timed and controlled. Identical meal-tolerance tests were performed at breakfast and dinner. Blood glucose, glucoregulatory hormones, and subjective appetite score were measured. Subcutaneous adipose tissue biopsies were performed and the transcriptome was assessed. RESULTS: The primary outcome, plasma glucose area under the curve, was altered by TRE, being unchanged at breakfast but increased at dinner. However, TRE reduced fasting glucose, glycated hemoglobin, body weight, and body fat, and increased glucose-dependent insulinotropic peptide area under the curve at dinner. In subcutaneous adipose tissue, 117 genes were up-regulated and 202 genes down-regulated by TRE. Pathway analysis revealed down-regulation of genes involved in proteasome function and mitochondrial regulation. CONCLUSIONS: TRE had a net effect of reducing glycemia and dampening energy-consuming pathways in adipose tissue.

Assessing temporal eating pattern in free living humans through the myCircadianClock app.

The quality and quantity of nutrition impact health. However, chrononutrition, the timing, and variation of food intake in relation to the daily sleep-wake cycle are also important contributors to health. This has necessitated an urgent need to measure, analyze, and optimize eating patterns to improve health and manage disease. While written food journals, questionnaires, and 24-hour dietary recalls are acceptable methods to assess the quantity and quality of energy consumption, they are insufficient to capture the timing and day-to-day variation of energy intake. Smartphone applications are novel methods for information-dense real-time food and beverage tracking. Despite the availability of thousands of commercial nutrient apps, they almost always ignore eating patterns, and the raw real-time data is not available to researchers for monitoring and intervening in eating patterns. Our lab developed a smartphone app called myCircadianClock (mCC) and associated software to enable long-term real-time logging that captures temporal components of eating patterns. The mCC app runs on iOS and android operating systems and can be used to track multiple cohorts in parallel studies. The logging burden is decreased by using a timestamped photo and annotation of the food/beverage being logged. Capturing temporal data of consumption in free-living individuals over weeks/months has provided new insights into diverse eating patterns in the real world. This review discusses (1) chrononutrition and the importance of understanding eating patterns, (2) the myCircadianClock app, (3) validation of the mCC app, (4) clinical trials to assess the timing of energy intake, and (5) strengths and limitations of the mCC app.

Time-restricted Eating for the Prevention and Management of Metabolic Diseases.

Time-restricted feeding (TRF, animal-based studies) and time-restricted eating (TRE, humans) are an emerging behavioral intervention approach based on the understanding of the role of circadian rhythms in physiology and metabolism. In this approach, all calorie intake is restricted within a consistent interval of less than 12 hours without overtly attempting to reduce calories. This article will summarize the origin of TRF/TRE starting with concept of circadian rhythms and the role of chronic circadian rhythm disruption in increasing the risk for chronic metabolic diseases. Circadian rhythms are usually perceived as the sleep-wake cycle and dependent rhythms arising from the central nervous system. However, the recent discovery of circadian rhythms in peripheral organs and the plasticity of these rhythms in response to changes in nutrition availability raised the possibility that adopting a consistent daily short window of feeding can sustain robust circadian rhythm. Preclinical animal studies have demonstrated proof of concept and identified potential mechanisms driving TRF-related benefits. Pilot human intervention studies have reported promising results in reducing the risk for obesity, diabetes, and cardiovascular diseases. Epidemiological studies have indicated that maintaining a consistent long overnight fast, which is similar to TRE, can significantly reduce risks for chronic diseases. Despite these early successes, more clinical and mechanistic studies are needed to implement TRE alone or as adjuvant lifestyle intervention for the prevention and management of chronic metabolic diseases.

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.

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.

A Smartphone Intervention to Promote Time Restricted Eating Reduces Body Weight and Blood Pressure in Adults with Overweight and Obesity: A Pilot Study.

The goal of this study was to test the feasibility of time restricted eating (TRE) in adults with overweight and obesity. Participants (n = 50) logged all eating occasions (>0 kcal) for a 2-week run-in period using a smartphone application. Participants with eating duration ≥14 h enrolled in an open label, non-randomized, prospective 90-day TRE intervention, with a self-selected reduced eating window of 10 h. No dietary counseling was provided. Changes in anthropometrics, eating patterns and adherence after TRE were analyzed using t-tests or Wilcoxon Rank-Sum Test. The mean duration of the baseline eating window was 14 h 32 m ± 2 h 36 m (n = 50) with 56% of participants with duration ≥14 h. TRE participants (n = 16) successfully decreased their eating window from 16 h 04 m ± 1 h 24 m to 11 h 54 m ± 2 h 06 m (p < 0.001), and reduced the number of daily eating occasions by half (p < 0.001). Adherence to logging and to the reduced eating window was 64% ± 22% and 47% ± 19%, respectively. TRE resulted in decreases in body weight (-2.1 ± 3.0 kg, p = 0.017), waist circumference (-2.2 ± 4.6 cm, p = 0.002) and systolic blood pressure (-12 ± 11 mmHg, p = 0.002). This study demonstrates the feasibility and efficacy of TRE administered via a smartphone, in adults with overweight and obesity.

Protocol for a randomised controlled trial on the feasibility and effects of 10-hour time-restricted eating on cardiometabolic disease risk among career firefighters doing 24-hour shift work: the Healthy Heroes Study.

INTRODUCTION: Career firefighters experience chronic circadian rhythm disruption, increasing their risk of cardiometabolic disease. The recent discovery that eating patterns regulate circadian rhythmicity in metabolic organs has raised the hypothesis that maintaining a consistent daily cycle of eating and fasting can support circadian rhythms and reduce disease risks. Preclinical animal studies and preliminary clinical trials have shown promising effects of time-restricted eating (TRE) to reduce disease risk without compromising physical performance. However, there is a lack of research on TRE in shift workers including firefighters. This study aims to investigate the feasibility and efficacy of 10-hour TRE on health parameters that contribute to cardiometabolic disease risks among career firefighters who work on a 24-hour shift schedule. METHODS AND ANALYSES: The Healthy Heroes Study is a randomised controlled parallel open-label clinical trial with 150 firefighters over 1 year. Firefighters are randomised with a 1:1 ratio to either the control or intervention group. The control group receives Mediterranean diet nutritional counselling (standard of care, 'SOC'). The intervention group receives the same SOC and a self-selected 10-hour TRE window. After the 2-week baseline, participants enter a 3-month monitored intervention, followed by a 9-month self-guided period with follow-up assessments. The impact of TRE on blood glucose, body weight, body composition, biomarkers (neuroendocrine, inflammatory and metabolic), sleep and mood is evaluated. These assessments occur at baseline, at the end of intervention and at 6, 9 and 12-month follow-ups. Temporal calorie intake is monitored with the smartphone application myCircadianClock throughout the study. Continuous glucose monitors, wrist-worn actigraphy device and questionnaires are used to monitor glucose levels, activity, sleep and light exposure. ETHICS AND DISSEMINATION: The study was approved by the Institutional Review Boards of the University of California San Diego and the Salk Institute for Biological Studies. Results will be disseminated through peer-reviewed manuscripts, reports and presentations. TRIAL REGISTRATION NUMBER: NCT03533023; Pre result.