Time-restricted eating: Watching the clock to treat obesity

Efficacy of time restricted eating and resistance training on body composition and mood profiles among young adults with overweight/obesity: a randomized controlled trial

BACKGROUND/OBJECTIVE

Dietary restriction or exercise regimens can promote weight loss or physical fitness among patients with obesity. However, intervention-associated adverse effects may impede patients' motivation to participate in dietary/exercise interventions. We examined the effects of time restricted eating (TRE) with or without resistance training (RT) on body composition, mood profile, and sleep quality in young college adults with overweight or obesity.

METHODS

Fifty-four young college students with overweight/obesity were randomized into control (CON), TRE, RT, and TRE plus RT (TRE+RT) trials. The TRE trials restricted to an eating window of 10-hour/day for 8-week. The RT trials performed supervised resistance exercise, while the control trial maintained a regular lifestyle. Changes in body composition variables, blood pressure, mood status, and sleep quality were measured before and after the intervention.

RESULTS

TRE intervention alone or in combination with RT significantly (p < 0.01) decreased body weight (>2 kg) and BMI (~1 kg/m2) in adults with overweight/obesity. Both RT alone and combined with TRE substantially decreased fat mass by 1.1 ± 0.5 and 3.2 ± 0.4 kg, respectively. The decreased fat mass was greater in the combination trial than in the RT trial, whereas TRE alone had no effect. In contrast, fat-free mass was significantly (p < 0.01) decreased with TRE (-2.3 ± 06 kg), increased with RT (1.6 ± 0.3 kg), and was stably maintained with combination interventions. The reduced waist and hip circumferences in the TRE (p < 0.01) were similar to those in the TRE+RT trials, however, RT alone had no effect. Time and group interaction showed a large effect size (partial eta squared) for all body composition variables. In addition, RT with or without TRE notably decreased diastolic blood pressure (RT: -5.5 ± 1.9 mmHg, TRE+RT: -4.1 ± 1.5 mmHg, p < 0.05). Mild anxiety levels at baseline in RT (4.8 ± 2.6) and TRE+RT (4.1 ± 3) trials were found to be normal at postintervention in TRE+RT (3.6 ± 1.7) but not in RT (5.6 ± 3.5). No depression or stress was recorded among the participants during the intervention. The reported poor sleep quality among participants at baseline was significantly improved with RT (4.8 ± 2.9; p < 0.05), and tended to improve with TRE+RT interventions (4.5 ± 1.9).

CONCLUSIONS

10-hour TRE is beneficial for weight/fat loss without affecting mood status. However, TRE combined with RT might be more effective for weight/fat loss, maintaining muscle mass, and good quality of sleep among young adults with overweight or obesity.

Food insecurity promotes adiposity in mice

OBJECTIVE

The obesity epidemic, driven by a complex interplay of environmental and biological factors, remains a significant global health challenge. Herein, we investigate the impact of food insecurity, characterized by unpredictable food access, on the regulation of body weight and body composition in mice.

METHODS

Male and female C57BL/6J mice were subjected to a combination of intermittent fasting and calorie restriction to simulate food insecurity.

RESULTS

Our new model demonstrates that food insecurity increases fat mass and decreases lean mass in both sexes on a standard chow diet. Additionally, high-fat diet-fed male mice exposed to the food insecurity paradigm show decreased lean mass despite being in positive energy balance. Transcriptomic analysis of white adipose tissue from food-insecure male mice revealed upregulation of metabolic pathways associated with fat mass expansion and downregulation of immune response-related transcripts.

CONCLUSIONS

These findings underscore the role of food insecurity in driving metabolic adaptations that favor fat storage. Understanding this paradoxical link between food insecurity and adiposity is crucial for developing targeted interventions to address the disproportionate incidence of obesity in socioeconomically disadvantaged populations.

Time-Restricted Feeding Promotes Longevity and Gut Health Without Fitness Trade-Offs

Time-restricted feeding (TRF), a dietary intervention involving daily fasting periods, has been associated with metabolic benefits; however, its long-term physiological impact remains unclear. Using Drosophila melanogaster as a model, we investigated the effects of a 16:8 TRF regimen on lifespan, reproductive output, gut health, and microbiota composition. TRF significantly extended lifespan, even when applied only during early adulthood. Notably, this longevity benefit occurred without compromising reproductive fitness, as measured by female fecundity in life's most crucial reproductive phase. TRF promoted gut homeostasis in aged flies by reducing intestinal stem cell proliferation and enhancing epithelial barrier integrity. Furthermore, TRF induced a shift in microbiota composition, increasing the prevalence of gram-negative bacterial taxa. These results show that even short-term TRF interventions at a young age can have long-term physiological benefits. Metabolic reprogramming or increased autophagy are the most likely mechanisms mediating the health-promoting effects of this type of nutritional intervention. TRF is an effective, non-invasive strategy for promoting healthy longevity without significant adverse effects on other aspects of life.

Comparison of Different Intermittent Fasting Patterns or Different Extents of Calorie Restriction for Weight Loss and Metabolic Improvement in Adults: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

CONTEXT

Continuous energy restriction (CER) and intermittent fasting (IF) are both prevalent diet regimens recommended for weight loss and metabolic improvement.

OBJECTIVE

The objective of this study was to evaluate the efficacy of CER and IF on weight loss and metabolic improvement in adults with overweight, obesity, or metabolic abnormalities.

DATA SOURCES

PubMed, Embase, and the Cochrane Library (CENTRAL) were searched for randomized controlled trials of 3 degrees of CER diet regimens and 4 categories of IF diet regimens, from inception of the databases to December 2022.

DATA EXTRACTION

Two reviewers independently extracted demographic information, the intervention duration, details of the dietary interventions, and data on the outcomes of interest.

DATA ANALYSIS

Bayesian random-effect network meta-analyses were used to pool the results and the Grading of Recommendations, Assessment, Development, and Evaluation framework was used to assess the certainty of the evidence and to present the findings.

RESULTS

The study included 167 eligible trials with a total enrollment of 11 998 participants. Most IF diet regimens induced significant weight loss that was comparable with that induced by CER diet regimens with a similar absolute energy restriction, based on low- to high-certainty evidence. Severe CER proved to be the most effective regimen for obtaining weight loss, based on moderate-certainty evidence (mean difference of weight change 11.50 kg [95% CI 10.07 to 12.93]), followed by alternate-day fasting, based on high-certainty evidence (mean difference of weight change (5.07 kg [95% CI 3.44 to 6.72]) and moderate CER, based on moderate-certainty evidence (6.09 kg [95% CI 5.26 to 6.93]), when the regimens being compared were consistent in their absolute energy restriction extent. Similar results were noticed for body measurements, blood pressure, blood lipids, and glycemic profiles. In the subgroup analysis, the weight-loss effects of the IF but not the CER diet regimens experienced rebound after 12 weeks.

CONCLUSION

In adults with overweight, obesity, or metabolic abnormalities, effectiveness in weight loss mainly depends on the extent of the energy restriction, regardless of the mealtime patterns.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022379621.

Time-restricted eating improves appetite regulation and sleep characteristics in adults with poor sleep quality

BACKGROUND & AIMS

Time-restricted eating (TRE), a type of intermittent fasting (IF), appears to improve metabolic health in adults but shows inconsistent effects on appetite and sleep regulation, with less data on adults with poor sleep. Our study evaluated the impact of TRE on appetite and nighttime sleep in individuals with normal-weight and inadequate sleep.

METHODS

A randomized controlled trial involved 30 young (age: 25.7 ± 5.6 years; 21F), normal-weight (body mass index (BMI): 23.0 ± 1.8 kg/m2) adults with poor sleep (<7 h/night or poor quality). Participants were randomized to two groups for 8 weeks: i) control group (CON), maintaining usual eating habits (CON, n = 16) or ii) time-restricted eating group (TRE), following a self-selected 10-h eating window (mandatory fasting from 23:00 to 06:00) for 8 weeks with no dietary changes (TRE, n = 14). Appetite, satiety, and craving for food were assessed using Visual Analog Scales (VAS) and the Food Craving Inventory-SP (FCI-SP), respectively. Sleep duration and quality were evaluated by using the Pittsburgh Sleep Quality Index (PSQI) and 7-day actigraphic recordings.

RESULTS

The TRE group reported higher satiety and fullness feeling together with a lower capacity to eat compared to CON (p < 0.038), while overall craving scores showed no between-group differences (p = 0.381). Sleep duration did not differ between groups, whereas several sleep characteristics improved. After TRE intervention, actigraphic assessments revealed an earlier sleep onset and later wake-up time (both p < 0.001) and fewer movements during sleep (p < 0.025).

CONCLUSION

An 8-week, 10-h TRE protocol positively affects appetite regulation and sleep characteristics in normal-weight young adults with insufficient or poor sleep. TRE appears promising for addressing appetite regulation and sleep disturbances in this group.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT06485037).

Protocol for a 1-year randomised, controlled, parallel group, open-label trial on the effects and feasibility of time-restricted eating in individuals with type 2 diabetes- The REStricted Eating Time in the treatment of type 2 diabetes (RESET2) trial

AIM

Time-restricted eating (TRE) limits the time for food intake to typically 6-10 h/day without other dietary restrictions. The aim of the RESET2 (the REStricted Eating Time in the treatment of type 2 diabetes) trial is to investigate the effects on glycaemic control (HbA1c) and the feasibility of a 1-year TRE intervention in individuals with overweight/obesity and type 2 diabetes. The aim of the present paper is to describe the protocol for the RESET2 trial.

METHODS

RESET2 is a randomised, controlled, parallel-group, open-label trial. One hundred and sixty individuals with type 2 diabetes (HbA1c >53 mmol/mol (>7.0%)), and Body Mass Index ≥25 kg/m2 will be randomised to standard care plus TRE, or to standard care and habitual living. Both the intervention and control group will follow standard diabetes care including regular clinical visits 3-4 times/year. The intervention is divided into two periods: (1) a 3-month TRE period with a fixed eating window with a self-selected timing to obtain data from the participants' experiences with TRE and (2) a 9-month individually adjusted TRE period. Participants in the TRE group will be instructed to reduce their eating window by a minimum of 3 h/day compared to the habitual eating window and with an eating window of 8-10 h/day. Test days will be scheduled at baseline, after 3 months and after 1 year. The primary outcome is HbA1c (evaluated 3 months and 1 year after randomisation) and secondary outcomes are body weight, fat mass, continuous glucose monitoring derived time-in-range and use of antidiabetic medicine (evaluated 1 year after randomisation). Additionally, we will conduct a process evaluation to assess whether the TRE intervention functioned as hypothesised.

Later eating timing in relation to an individual internal clock is associated with lower insulin sensitivity and affected by genetic factors

BACKGROUND

Although the contribution of the circadian clock to metabolic regulation is widely recognized, the role of eating timing in glucose metabolism and diabetes risk remains insufficiently studied. This study aimed (i) to investigate the link between the eating timing pattern relative to individual clock and glucose homoeostasis and (ii) to explore the contribution of genetic and environmental factors to eating timing parameters.

METHODS

In 92 adult twins (NCT01631123), glycaemic traits were assessed using the oral glucose tolerance test. Parameters of eating timing pattern (eating timing itself, daily calorie distribution, and eating frequency) were extracted from five-day food records. Caloric midpoint defined as the time point at which 50% of daily calories are consumed. Circadian timing of eating was determined as a time interval between the clock time of eating and a corrected midpoint of sleep, a chronotype marker. Heritability of eating timing components was estimated by comparing correlations within monozygotic and dizygotic twin pairs and fitting genetic structural equation models.

FINDINGS

Among components of eating timing, the most associations were found for the circadian time of caloric midpoint (CCM). Later CCM was significantly associated with poorer insulin sensitivity, i.e. with lower ISI Stumvoll (β = 0.304, p = 5.9 × 10-4) and higher HOMA-IR (β = -0.258, p = 0.011) indices, as well as with higher fasting insulin levels (β = -0.259, p = 0.013), even after the model adjustment for sex, age, daily energy intake, and sleep duration. Later CCM also demonstrated robust associations with higher BMI and waist circumference. All eating timing components showed high or moderate heritability and were strongly related to individual sleep timing.

INTERPRETATION

Later eating timing in relation to an individual internal clock is associated with lower insulin sensitivity. Shifting the main calorie intake to earlier circadian times may improve glucose metabolism, but genetic factors could influence the feasibility and effectiveness of eating-timing based interventions. The findings should be investigated in a larger cohort.

FUNDING

This work was supported by the German Research Foundation (DFG RA 3340/4-1 to OP-R, project number 530918029), by the European Association for the Study of Diabetes (Morgagni Prize 2020 to OP-R), and by the German Federal Ministry of Education and Research (BMBF NUGAT 0315424 to AFHP). The DZD is funded by the German Federal Ministry for Education and Research (01GI0925).

Time-Restricted Eating is a Feasible Dietary Strategy in the Treatment of Complicated Type 2 Diabetes: The RESET2 Pilot Study

OBJECTIVE

To investigate the feasibility of a 12-week time-restricted eating (TRE) intervention targeting people with overweight/obesity and complicated type 2 diabetes to inform the design of a 1-year randomized controlled trial.

METHODS

In this single-arm pilot study, 20 participants with overweight/obesity and complicated type 2 diabetes were recruited from the diabetes clinics at Hvidovre Hospital and Steno Diabetes Center Copenhagen in the Greater Copenhagen area, Denmark. Participants followed 8 weeks of strict 10-hour TRE, followed by a 4-week TRE period with individual adjustments and support options.

RESULTS

Nineteen participants completed the intervention. Median (quartile 1-quartile 3) adherence to the eating window across all 12 weeks was 94% (86-98). Mean (95% confidence interval) reductions in body weight of -2.0 kg (-2.9 to -1.1) and hemoglobin A1c of -0.4% (-0.6 to -0.1) were observed. Participants expressed that the individualized options added flexibility to the eating concept, enabled the maintenance of social life, and eased challenging times with TRE.

CONCLUSIONS AND IMPLICATIONS

Twelve weeks of TRE was feasible. Individualized adjustments and support may have the potential to facilitate the maintenance of long-term TRE.

Maintenance of time-restricted eating and high-intensity interval training in women with overweight/obesity 2 years after a randomized controlled trial

Time-restricted eating (TRE) and high-intensity interval training (HIIT) improve cardiometabolic health in individuals with overweight/obesity, with high adherence rates in supervised settings. Long-term maintenance of TRE and HIIT in real-world settings is unknown. In our previous TREHIIT trial, 131 women (body mass index (BMI) ≥ 27 kg/m2) were randomized to 7 weeks of TRE (eating window 10-h/day), HIIT (3 sessions/week), a combination (TREHIIT), or no intervention (CON). We investigated self-reported continuation of TRE and/or HIIT after 2 years. Fifty-nine participants (39.0 years (standard deviation (SD) 6.1), BMI 30.7 kg/m2 (SD 4.2)) attended the follow-up. Of those who completed the 7-week TRE or HIIT intervention, 46% maintained TRE and 45% continued HIIT for 2 years. There were no statistically significant (at p < .01) between-group differences in cardiometabolic outcomes, but non-significant lower body mass in HIIT (-4.2 kg, 95% confidence interval (CI), -7.7 to -0.7, p = .019) and visceral fat in TREHIIT (-18 cm2, CI, -33 to -4, p = .015) versus CON. After 2 years, HIIT and TREHIIT had ~ 4 kg lower fat mass and ~ 20 cm² lower visceral fat (both p < .001) compared with baseline. A short-term TRE and HIIT intervention may promote long-term lifestyle changes and health benefits. Future studies should collect objective adherence data to understand long-term maintenance of TRE and HIIT.

The metabolic significance of peripheral tissue clocks

The circadian clock is a transcriptional-translational feedback loop which oscillates in virtually all nucleated cells of the body. In the decades since its discovery, it has become evident that the molecular clockwork is inextricably linked to energy metabolism. Given the frequency with which metabolic dysfunction and clock disruption co-occur, understanding why and how clock and metabolic processes are reciprocally coupled will have important implications for supporting human health and wellbeing. Here, we discuss the relevance of molecular clock function in metabolic tissues and explore its role not only as a driver of day-night variation in gene expression, but as a key mechanism for maintaining metabolic homeostasis in the face of fluctuating energy supply and demand.

Unraveling the gut microbiota's role in PCOS: a new frontier in metabolic health

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder affecting reproductive-age women, characterized primarily by hyperandrogenism, ovulatory dysfunction, and metabolic abnormalities. In recent years, the gut microbiota has garnered widespread attention for its potential role as a key regulator of host metabolism in the pathogenesis of PCOS. Studies have shown that PCOS patients exhibit dysbiosis in their gut microbiota, characterized by reduced microbial diversity, an imbalance in the ratio of Firmicutes to Bacteroidetes, changes in the abundance of specific taxa, and abnormal levels of metabolic products. These alterations may exacerbate metabolic dysfunction in PCOS through multiple mechanisms, including influencing host energy metabolism, disrupting lipid and bile acid metabolism, and inducing chronic inflammation. Addressing gut dysbiosis through the modulation of patients' microbiomes-such the use of, prebiotics, fecal microbiota transplantation, and optimizing diet lifestyle-may offer strategies for improving metabolic abnormalities and alleviating clinical symptoms in PCOS. Additionally, the gut microbiome promises as a potential marker, aiding in the precise diagnosis and personalization of PCOS. Although our current understanding of how the gut microbiota influences PCOS is still limited, research is needed to explore the causal relationships and mechanisms involved, providing a more reliable theoretical basis for clinical. This review aims summarize the research progress on the relationship between gut microbiota and PCOS, and to suggest future directions to promote the development of prevention and treatment strategies for PCOS.

The relationship between chrononutrition profile, social jet lag and obesity: A cross-sectional study of Chinese college students

This study aimed to investigate the associations between chrononutrition profile, social jet lag (SJL) with obesity-related indicators (body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHTR), and percentage of body fat (PBF)). This cross-sectional study was conducted among college students in a university in Hunan Province, China, from 14 September 2023 to 8 June 2024. This study employed the Chrononutrition Profile - Questionnaire (CP-Q) along with physical examinations. SJL was defined as time difference of midpoint of sleep between the workdays and freedays. Sleep-corrected SJL (SJLsc) is the absolute difference between the sleep onset on free days and workdays. Average evening latency is the time between the last meal of the day and bedtime. Eating jet lag is the difference in the midpoint of the eating window between workdays and freedays. Logistic regression was utilized to assess the associations between chrononutrition profile, SJL, and obesity-related indicators among college students. A total of 805 participants were recruited, of which 695 have complete data after excluding those who did not meet the inclusion criteria. After adjusting for potential covariates, average evening latency <4 h was related with lower risk of high BMI, WC, and PBF [OR (95% CI) = 0.435 (0.285-0.663), 0.508 (0.305-0.848), 0.564 (0.402-0.792), respectively]. Average eating window >12 h was associated with a lower risk of high BMI, WC, and PBF [OR (95% CI) = 0.511 (0.327-0.800), 0.485 (0.277-0.851), 0.651 (0.456-0.930), respectively]. Last eating occasion jet lag >1 h was a higher risk of high PBF [OR (95% CI) = 1.554 (1.018-2.371)]. SJLsc > 1 h was associated with high PBF [OR (95% CI) = 1.527 (1.073-2.174)]. Circadian rhythm disruptions, including SJL and eating jet lag, are prevalent among college students. Long eating window, short evening latency, is associated with low risk of obesity, while short sleep duration, last eating occasion jet lag and larger SJLsc were associated with higher risk of obesity among youths.

Circadian Disruption and the Risk of Developing Obesity

PURPOSE OF THE REVIEW

This review summarizes recent evidence for a role of the clock in adipose tissue physiology and the impact of circadian desynchrony on the development of obesity.

RECENT FINDINGS

Circadian disruptions due to shift work, late time eating and nighttime light exposure are associated with obesity and its metabolic and cardiovascular consequences. Studies in mice harboring tissue-specific gain/loss of function mutations in clock genes revealed that the circadian clock acts on multiple pathways to control adipogenesis, lipogenesis/lipolysis and thermogenesis. Time-restricted eating (TRE), aligning feeding with the active period to restore clock function, represents a promising strategy to curb obesity. While TRE has shown clear benefits, especially in participants at higher cardiometabolic risk, current studies are limited in size and duration. Larger, well-controlled studies are warranted to conclusively assess the effects of TRE in relation to the metabolic status and gender. Field studies in shift-workers, comparing permanent night shift versus rotating shifts, are also necessary to identify the optimal time window for TRE.

Overcoming dietary complexity in type 2 diabetes: influencing factors and coping strategies

BACKGROUND

Adherence to dietary guidelines is a fundamental aspect of diabetes management; however, it poses a significant challenge for patients with diabetes. Our research aims to assess the level of dietary compliance among individuals with type 2 diabetes (T2DM) and to identify the factors that influence their adherence to dietary advice.

METHODS

This study was a cross-sectional survey. The patients with T2DM undergoing treatment at our hospital from March, 2023, to June, 2024 were included. Compliance with dietary recommendations was assessed using the validated dietary compliance scale for type 2 diabetes mellitus patients (DCS-T2DM). Spearman correlation and logistic regression analyses were conducted to evaluate the factors influencing dietary compliance in patients with T2DM.

RESULTS

A total of 308 T2DM patients were included in our study. The results revealed that 46.10% of the participants had suboptimal dietary compliance. There were significant correlations between dietary compliance and several demographic and clinical factors, including age (r = 0.501), gender (r = 0.447), education level (r = 0.610), average monthly household per capita income (r = 0.627), and the duration, since T2DM diagnosis (r = 0.552), all of which were statistically significant (p < 0.05). Logistic regression identified age (OR = 1.705, 95%CI 1.262 ~ 1.987), gender (OR = 2.401, 95%CI 1.909 ~ 3.134), education level (OR = 3.083, 95%CI 2.434 ~ 3.957), average monthly household per capita income (OR = 3.721, 95%CI 2.553 ~ 4.405), and the time since T2DM diagnosis (OR = 2.470, 95%CI 1.755 ~ 3.262) as significant predictors of dietary compliance.

CONCLUSIONS

46.10% of patients with T2DM exhibited suboptimal dietary adherence, with age, gender, education, income, and diabetes duration significantly predicting compliance. It is imperative for healthcare providers to devise individualized intervention strategies that incorporate these pivotal factors to enhance dietary adherence in patients with T2DM.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Navigating challenges and adherence in time-restricted eating: A qualitative study

AIMS

Adherence to any dietary approach is crucial for achieving long-term benefits. This qualitative study aims to explore the facilitators and barriers to adherence, and how individuals in community settings navigate time-restricted eating in their daily lives.

METHODS

Semi-structured, in-depth interviews were conducted with 21 participants who had practised time-restricted eating (confining the daily eating window to <10h a day; and excluding periodic fasting methods like the 5:2 approach or alternate day fasting) for periods ranging from 3 months to more than 5 years. A qualitative content analysis, underpinned by the Capability-Opportunity-Motivation-Behaviour Model, identified multiple facilitators, barriers, and strategies that evolved over the practice.

RESULTS

Key facilitators included the simplicity and versatility of time-restricted eating, maintaining a non-obsessive and non-dieting mindset, and having a supportive environment. Barriers included hunger and food cravings, an obsessive mindset during the initial stages, and conflicting schedules with social eating occasions, including holidays. Participants employed several coping strategies to successfully navigate adherence and reported confidence in maintaining time-restricted eating as a lifestyle that contributes to better health and weight management.

CONCLUSION

Our findings suggest that successful implementation of time-restricted eating in community settings requires flexibility and viewing it as more than a short-term weight loss tool. Guidelines are needed to help individuals and practitioners implement better practices and promote healthier behaviours.

A Narrative Review of Intermittent Fasting With Exercise

Intermittent fasting is a dietary pattern that encompasses the 5:2 diet, alternate-day fasting, and time-restricted eating. All 3 involve alternating periods of fasting and ad libitum eating. Like other dietary strategies, intermittent fasting typically induces loss of both fat mass and lean mass. Exercise may thus be a useful adjuvant to promote lean mass retention while adding cardiometabolic, cognitive, mental, and emotional health improvements. In this narrative review, we summarize current evidence regarding the combination of intermittent fasting and exercise and its influence on body weight, body composition, cardiometabolic risk, and muscular and cardiorespiratory fitness. A PubMed search was conducted to identify all trials lasting >4 weeks that combined 5:2 diet, alternate-day fasting, or time-restricted eating with any modality exercise and had body weight as an end point. A total of 23 trials (26 publications) were identified. Evidence suggests that combining intermittent fasting with exercise leads to decreased fat mass regardless of weight status. However, evidence is equivocal for the influence on other aspects of weight loss and body composition, fat-free mass, and cardiometabolic risk factors and may be dependent on weight status or exercise doses (ie, frequency, intensity, duration, and modality). Higher-powered trials are needed to determine the efficacy of combining exercise and intermittent fasting for benefits on body weight and cardiometabolic risk. Current evidence suggests that intermittent fasting does not impair adaptation to exercise training, and may improve explosive strength, endurance, and cardiopulmonary measures such as maximal oxygen consumption. In addition, we discuss limitations in the current evidence base and opportunities for continued investigation. Future trials in this area should consider interventions that have increased sample size, longer intervention duration, broadened inclusion criteria, objective measures of diet and exercise adherence, and diversity of sample population.

Prevention of cardiometabolic diseases through dietary modifications

PURPOSE OF REVIEW

Cardiometabolic diseases (CMDs) increasingly contribute to the cumulative burden of morbidity and mortality worldwide. Here, we reviewed intervention studies using a randomized controlled trial (RCT) design as well as meta-analyses of RCTs aimed at testing the effectiveness of different dietary approaches for CMD prevention.

RECENT FINDINGS

Recent studies testing dietary approaches for CMD prevention were summarized narratively, with a focus on interventions based on caloric restriction and fasting, healthy dietary patterns and food-based dietary modifications. Evidence supports intermittent fasting, Mediterranean, Nordic, DASH, low-carbohydrate/ketogenic and plant-based diets as effective strategies for improving cardiometabolic health. However, the benefits observed with some of these dietary patterns are linked to energy restriction, and the independent effects beyond weight loss remain unclear. The effectiveness of some strategies may also depend on the overall dietary quality and adherence to the programme.

SUMMARY

Recent findings highlight the importance of focusing on overall dietary patterns, rather than isolated nutrients, for preventing CMD. Future research should prioritize long-term intervention studies to assess the sustained effects of these dietary patterns on CMD outcomes.

Effects of early, late and self-selected time-restricted eating on visceral adipose tissue and cardiometabolic health in participants with overweight or obesity: a randomized controlled trial

The optimal eating window for time-restricted eating (TRE) remains unclear, particularly its impact on visceral adipose tissue (VAT), which is associated with cardiometabolic morbidity and mortality. We investigated the effects of three TRE schedules (8 h windows in the early day, late day and participant-chosen times) combined with usual care (UC, based on education about the Mediterranean diet) versus UC alone over 12 weeks in adults with overweight or obesity. The primary outcome was VAT changes measured by magnetic resonance imaging. A total of 197 participants were randomized to UC (n = 49), early TRE (n = 49), late TRE (n = 52) or self-selected TRE (n = 47). No significant differences were found in VAT changes between early TRE (mean difference (MD): -4%; 95% confidence interval (CI), -12 to 4; P = 0.87), late TRE (MD: -6%; 95% CI, -13 to 2; P = 0.31) and self-selected TRE (MD: -3%; 95% CI, -11 to 5; P ≥ 0.99) compared with UC, nor among the TRE groups (all P ≥ 0.99). No serious adverse events occurred; five participants reported mild adverse events. Adherence was high (85-88%) across TRE groups. These findings suggest that adding TRE, irrespective of eating window timing, offers no additional benefit over a Mediterranean diet alone in reducing VAT. TRE appears to be a safe, well-tolerated and feasible dietary approach for adults with overweight or obesity. ClinicalTrials.gov registration: NCT05310721 .

Impact of Time-Restricted Eating and High-Intensity Exercise on Nutrient Intake in Women with Overweight/Obesity: Secondary Analysis of a Randomized Controlled Trial

BACKGROUND/OBJECTIVES

Inadequate micronutrient intakes are common in individuals with overweight/obesityand can exacerbate cardiovascular and metabolic disease risk. Diet and exercise are primary strategies for managing overweight and may influence nutrient intakes. In this secondary analysis of dietary data collected in a randomized controlled trial (RCT, ClinicalTrials.gov (NCT04019860), 15 June 2019) of time-restricted eating (TRE), high-intensity interval training (HIIT), a combination (TREHIIT), or a control group (CON), we investigated intervention effects on energy and nutrient intakes in women with overweight/obesity.

METHODS

We randomized 131 women (body mass index (BMI) ≥ 27 kg/m2) to 7 weeks of TRE (≤10-h daily eating window with ad libitum energy intake), HIIT (3 sessions/week, performed at ≥90% maximal heart rate), TREHIIT, or CON. Participants recorded all energy intake in an online food diary during a baseline week (week 0) and at the end of the study (week 6 and week 7). We investigated between-group differences in changes in mean energy, macronutrient, and micronutrient intakes.

RESULTS

TRE had reduced intakes of potassium, magnesium, and phosphorus compared with CON (p < 0.01). TREHIIT had non-significant reduced intakes of potassium, thiamine, magnesium, copper, and phosphorus (0.01< p < 0.05). HIIT alone did not negatively impact micronutrient intakes. TRE and TREHIIT induced suboptimal intakes for a greater number of micronutrients compared with HIIT and CON.

CONCLUSIONS

A ≤10-h TRE window might increase the risk of micronutrient inadequacy in women with overweight/obesity. Future research is needed to investigate the effects of integrating nutritional guidelines with TRE interventions to mitigate the risk of micronutrient inadequacy in individuals with overweight/obesity.

"It just made sense to me!" A Qualitative Exploration of Individual Motivation for Time-Restricted Eating

Time-Restricted Eating (TRE), a form of intermittent fasting, has gained popularity for weight control and metabolic health. It is not incorporated into dietary and clinical guidelines, and hence is generally not being recommended to the public. This qualitative study explores how individuals have discovered TRE as a form of dietary practice and their motivations for practising it. Using purposive and snowball sampling, we recruited 21 participants who had engaged in TRE for at least 3 months (range 3 months to over 5 years). In-depth interviews were conducted with an interview guide developed based on the Health Belief Model. We utilised an inductive coding process and thematic analysis to identify the factors motivating TRE adoption. Seven main themes emerged: (1) dissatisfaction and resistance to prior or traditional approaches, (2) perceived broader health benefits, (3) principles of TRE deemed logical, (4) low to no cost of adoption, (5) manageable psychosocial barriers, (6) being non-restrictive and easy to use, and (7) compatibility with personal lifestyle. This study provided insights into early phase of TRE adoption among individuals in real world settings. Future research should explore health practitioners' perspectives on TRE to better understand the acceptability and potential use of TRE as a weight management approach.

Dietary patterns to promote cardiometabolic health

Multiple professional societies recommend the Mediterranean and/or Dietary Approaches to Stop Hypertension dietary patterns in their cardiovascular disease prevention guidelines because these diets can improve cardiometabolic health and reduce the risk of cardiovascular events. Furthermore, low sodium intake can be particularly beneficial for patients with hypertension. Carbohydrate restriction, with an emphasis on including high-quality carbohydrates and limiting refined starches and foods and beverages with added sugars, can promote weight loss and cardiometabolic benefits in the short term, compared with higher carbohydrate intake. Evidence is lacking for sustained, long-term effects of low carbohydrate and very low carbohydrate intake on cardiometabolic risk and cardiovascular outcomes. Time-restricted eating, in the context of an overall healthy dietary pattern, can promote cardiometabolic health by aligning food intake with the circadian rhythm, although its effect on hard clinical outcomes remains to be proven. Although there is no one dietary pattern that is appropriate for all patients, engaging in shared decision-making with patients, utilizing behaviour-change principles and engaging members of the health-care team, such as registered dietitian nutritionists, can lead to substantial improvement in the lifestyle and overall health trajectory of a patient. Emphasizing the similarities, rather than differences, of recommended dietary patterns, which include an emphasis on vegetables, fruits, legumes, nuts, whole grains and minimally processed protein foods, such as fatty fish or plant-based proteins, can simplify the process for both patients and clinicians alike.

Intermittent fasting as a treatment for obesity in young people: a scoping review

Intermittent fasting focuses on the timing of eating rather than diet quality or energy intake, with evidence supporting its effects on weight loss and improvements in cardiometabolic outcomes in adults with obesity. However, there is limited evidence for its feasibility and efficacy in young people. To address this, a scoping review was conducted to examine intermittent fasting regimens in individuals aged 10 to 25 for the treatment of obesity focusing on methodology, intervention parameters, outcomes, adherence, feasibility, and efficacy. Due to the paucity of evidence in this age group, to adequately assess feasibility and adherence, all published studies of intermittent fasting in this age category, regardless of weight status and treatment intention, were included in the review. The review included 34 studies (28 interventional studies and 6 observational studies) with 893 participants aged 12 to 25. Interventions varied with 9 studies in cohorts with obesity utilizing intermittent fasting as an obesity treatment. Thirteen studies utilized 8-h time-restricted eating. Primary outcomes included cardiometabolic risk factors (7/28), anthropometric measurements (7/28), body composition (5/28), muscular performance (4/28), feasibility (1/28), and others (4/28). All 9 studies conducted in young people with obesity reported some degree of weight loss, although the comparator groups varied significantly. This review underscores the various utilizations of intermittent fasting in this age group and highlights its potential in treating obesity. However, the findings emphasize the need for rigorous studies with standardized frameworks for feasibility to ensure comparability and determine intermittent fasting's practicality in this age group depending on the treatment outcome of interest.

Time-Restricted Eating in Real-World Healthcare Settings: Utilisation and Short-Term Outcomes Evaluation

BACKGROUND

Time-restricted eating (TRE) shows promise for managing weight and metabolic issues, yet its application in real-world healthcare settings remains underexplored. This study aims to assess the real-world utilisation and short-term outcomes of TRE in clinical practice.

METHODS

This observational study used a retrospective chart review of 271 adults who attended a metabolic specialist clinic between 2019 and 2023. Descriptive statistics and multivariable logistic regression were used to identify factors associated with TRE adoption, while paired sample t-tests evaluated changes in outcomes among those who received TRE advice.

RESULTS

Among the 271 patients, 76% were female, 90% Caucasian, and 94% overweight/obese. Of all patients, 47.2% received TRE advice, mainly using the 16:8 method, alongside additional dietary guidance for 60% of patients. Working status and baseline metabolic profiles were the only factors significantly associated with TRE adoption. Among those who followed TRE, 81% experienced modest but significant reductions in weight (-1.2 kg, p < 0.01), BMI (-0.4 kg/m2, p < 0.01), and waist circumference (-3.7 cm, p < 0.01).

CONCLUSIONS

This study highlights TRE as a feasible and practical dietary strategy for improving metabolic health in healthcare settings. However, further research and improved data capture are needed to explore long-term adherence, potential adverse effects, and the effectiveness of TRE across diverse patient populations.

Quantitative analysis of the caloric restriction versus isocaloric diets models based on macronutrients composition: impacts on body weight regulation, anthropometric, and bioimpedance parameters in women with obesity

Introduction

Obesity is a growing public health issue, especially among young adults, with long-term management strategies still under debate. This prospective study compares the effects of caloric restriction and isocaloric diets with different macronutrient distributions on body composition and anthropometric parameters in obese women during a 12-week weight loss program, aiming to identify the most effective dietary strategies for managing obesity-related health outcomes.

Methods

A certified clinical nutritionist assigned specific diets over a 12-week period to 150 participants, distributed as follows: hypocaloric diets-low-energy diet (LED, 31 subjects) and very low-energy diet (VLED, 13 subjects); isocaloric diets with macronutrient distribution-low-carbohydrate diet (LCD, 48 subjects), ketogenic diet (KD, 23 subjects), and high-protein diet (HPD, 24 subjects); and isocaloric diet without macronutrient distribution-time-restricted eating (TRE, 11 subjects). Participants were dynamically monitored using anthropometric parameters: body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and bioelectrical impedance analysis (BIA) using the TANITA Body Composition Analyzer BC-418 MA III (T5896, Tokyo, Japan) at three key intervals-baseline, 6 weeks, and 12 weeks. The following parameters were evaluated: body weight, basal metabolic rate (BMR), percentage of total body fat, trunk fat, muscle mass, fat-free mass, and hydration status.

Results

All diets led to weight loss, but differences emerged over time. The TRE model resulted in significantly less weight loss compared to LED at the final follow-up (6.30 kg, p < 0.001), similar to the VLED (4.69 kg, p < 0.001). Isocaloric diets with varied macronutrient distributions showed significant weight loss compared to LED (p < 0.001). The KD reduced waist circumference at both 6 and 12 weeks (-4.08 cm, p < 0.001), while significant differences in waist-to-hip ratio reduction were observed across diet groups at 12 weeks (p = 0.01). Post-hoc analysis revealed significant fat mass differences at 12 weeks, with HPD outperforming IF (p = 0.01) and VLED (p = 0.003). LCD reduced trunk fat at 6 weeks (-2.36%, p = 0.001) and 12 weeks (-3.79%, p < 0.001). HPD increased muscle mass at 12 weeks (2.95%, p = 0.001), while VLED decreased it (-2.02%, p = 0.031). TRE showed a smaller BMR reduction at 12 weeks compared to LED.

Conclusion

This study highlights the superior long-term benefits of isocaloric diets with macronutrients distribution over calorie-restrictive diets in optimizing weight, BMI, body composition, and central adiposity.

Circadian de(regulation) in physiology: implications for disease and treatment

Time plays a crucial role in the regulation of physiological processes. Without a temporal control system, animals would be unprepared for cyclic environmental changes, negatively impacting their survival. Experimental studies have demonstrated the essential role of the circadian system in the temporal coordination of physiological processes. Translating these findings to humans has been challenging. Increasing evidence suggests that modern lifestyle factors such as diet, sedentarism, light exposure, and social jet lag can stress the human circadian system, contributing to misalignment; i.e., loss of phase coherence across tissues. An increasing body of evidence supports the negative impact of circadian disruption on several human health parameters. This review aims to provide a comprehensive overview of how circadian disruption influences various physiological processes, its long-term health consequences, and its association with various diseases. To illustrate the relevant consequences of circadian disruption, we focused on describing the many physiological consequences faced by shift workers, a population known to experience high levels of circadian disruption. We also discuss the emerging field of circadian medicine, its founding principles, and its potential impact on human health.

Fasting as an Adjuvant Therapy for Cancer: Mechanism of Action and Clinical Practice

The fundamental biological characteristics of tumor cells are characterized by irregularities in signaling and metabolic pathways, which are evident through increased glucose uptake, altered mitochondrial function, and the ability to evade growth signals. Interventions such as fasting or fasting-mimicking diets represent a promising strategy that can elicit distinct responses in normal cells compared to tumor cells. These dietary strategies can alter the circulating levels of various hormones and metabolites, including blood glucose, insulin, glucagon, growth hormone, insulin-like growth factor, glucocorticoids, and epinephrine, thereby potentially exerting an anticancer effect. Additionally, elevated levels of insulin-like growth factor-binding proteins and ketone bodies may increase tumor cells' dependence on their own metabolites, ultimately leading to their apoptosis. The combination of fasting or fasting-mimicking diets with radiotherapy or chemotherapeutic agents has demonstrated enhanced anticancer efficacy. This paper aims to classify fasting, elucidate the mechanisms that underlie its effects, assess its impact on various cancer types, and discuss its clinical applications. We will underscore the differential effects of fasting on normal and cancer cells, the mechanisms responsible for these effects, and the imperative for clinical implementation.

Calenduloside E Ameliorates Inflammatory Responses in Adipose Tissue via Sirtuin 2-NLRP3 Inflammasome Axis

Obesity-related metabolic diseases are associated with a chronic inflammatory state. Calenduloside E (CE) is a triterpene saponin from sugar beet. In mouse models, CE reduced pro-inflammatory cytokines in white adipose tissue (WAT) and decreased macrophage infiltration of WAT. And CE inhibited pyroptosis in J774A.1 cells and WAT by inhibiting the activation of the nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3 (NLRP3) inflammasome. Moreover, CE could trigger the activation of Sirtuin 2 (SIRT2), leading to a decrease in the acetylation of NLRP3, particularly at the K24 site. In addition, it has been shown that CE can reduce inflammation in adipocytes that have been induced by macrophage-conditioned medium. However, the selective SIRT2 inhibitor AGK2 hindered the beneficial effects of CE. In summary, CE has the capacity to impede NLRP3-mediated pyroptosis by triggering SIRT2 activity, thus positioning CE as a promising therapeutic avenue for combating obesity-related metabolic disorders.

Effect of time restricted eating versus daily calorie restriction on sex hormones in males and females with obesity

This study examined the effects of time restricted eating (TRE) on sex hormones in males and females, versus daily calorie restriction (CR). Adults with obesity (n = 90) were randomized to 1 of 3 groups for 12-months: 8-h TRE (eating only between 12:00 to 8:00 pm, with no calorie counting); CR (25% energy restriction daily); or control. Body weight decreased (P < 0.01) in the TRE and CR groups, relative to controls, in males, premenopausal females, and postmenopausal females, by month 12. Total testosterone, dehydroepiandrosterone (DHEA), and sex hormone binding globulin (SHBG) levels did not change over time, or between groups, in males, premenopausal females, and postmenopausal females. Estradiol, estrone, and progesterone were only measured in postmenopausal females, and remained unchanged. These findings suggest that TRE produces significant weight loss but does not impact circulating sex hormone levels in males and females with obesity over 12 months, relative to CR and controls.

Adipose thermogenic mechanisms by cold, exercise and intermittent fasting: Similarities, disparities and the application in treatment

Given its nonnegligible role in metabolic homeostasis, adipose tissue has been the target for treating metabolic disorders such as obesity, diabetes and cardiovascular diseases. Besides its lipolytic function, adipose thermogenesis has gained increased interest due to the irreplaceable contribution to dissipating energy to restore equilibrium, and its therapeutic effects have been testified in various animal models. In this review, we will brief about the canonical cold-stimulated adipose thermogenic mechanisms, elucidate on the exercise- and intermittent fasting-induced adipose thermogenic mechanisms, with a focus on the similarities and disparities among these signaling pathways, in an effort to uncover the overlapped and specific targets that may yield potent therapeutic efficacy synergistically in improving metabolic health.

Long-term Metabolic Dysfunction Programming in Female Mice by Serial Moderate Restriction of a High-fat High-sucrose Diet

BACKGROUND

While intermittent fasting leads to weight loss and improved glucose metabolism, food insecurity, the insufficient access to food for a healthy life, is associated with obesity and adverse cardiometabolic health, especially in women. We aimed to characterize the effects of intermittently restricted feeding on energy balance and glucose tolerance in female mice.

METHODS

Female C57BL/6J mice were fed a high-fat, high-sucrose diet and intermittently food restricted to 60% of control littermates' ad libitum intake, starting at weaning and until week 19. Restricted mice were subsequently allowed ad libitum access to the same diet. Body composition and energy balance were measured at weeks 18.5, 19, 30, and 40. At week 42, mice underwent an intraperitoneal glucose tolerance test and plasma appetitive hormones measurements after nutrient gavage.

RESULTS

During the food restriction phase, restricted mice accrued lower weight and fat mass than controls despite periodic ad libitum food access. Reintroduction of continuous ad libitum food caused increased food intake during the light phase and increased body mass in restricted mice. Minor differences in body composition-adjusted energy expenditure between groups were observed at week 40. At week 42, glucose tolerance was impaired in restricted mice compared to controls, and trends toward lower levels of postprandial anorexigenic hormones glucagon-like peptide-1 and pancreatic polypeptide were observed.

CONCLUSION

Our findings suggest that repeated intermittent food restriction leads to changes in eating behavior that predispose to glucose intolerance when food is freely available. Future studies are needed to elucidate the specific mechanisms underlying these changes.

Effect of Time-Restricted Eating on Sleep in Type 2 Diabetes

The aim of this secondary analysis was to compare the effects of time-restricted eating (TRE) versus calorie restriction (CR) and controls on sleep in adults with type 2 diabetes (T2D). Adults with T2D (n = 75) were randomized to 1 of 3 interventions for 6 months: 8 h TRE (eating only between 12 and 8 pm daily); CR (25% energy restriction daily); or control. Our results show that TRE has no effect on sleep quality, duration, insomnia severity, or risk of obstructive sleep apnea, relative to CR and controls, in patients with T2D over 6 months.

Optimizing the design of time-restricted eating human trials

Time-restricted eating has become a popular diet for weight management and has spurred tremendous interest in the scientific community. The translation of results from TRE trials heavily depends on trial design. In this Comment, we provide general guidelines on optimizing the design and performance of time-restricted eating trials in human participants.

Digesting the complex metabolic effects of diet on the host and microbiome

The past 50 years of interdisciplinary research in humans and model organisms has delivered unprecedented insights into the mechanisms through which diet affects energy balance. However, translating these results to prevent and treat obesity and its associated diseases remains challenging. Given the vast scope of this literature, we focus this Review on recent conceptual advances in molecular nutrition targeting the management of energy balance, including emerging dietary and pharmaceutical interventions and their interactions with the human gut microbiome. Notably, multiple current dietary patterns of interest embrace moderate-to-high fat intake or prioritize the timing of eating over macronutrient intake. Furthermore, the rapid expansion of microbiome research findings has complicated multiple longstanding tenets of nutrition while also providing new opportunities for intervention. Continued progress promises more precise and reliable dietary recommendations that leverage our growing knowledge of the microbiome, the changing landscape of clinical interventions, and our molecular understanding of human biology.

Caloric and time restriction diets improve acute kidney injury in experimental menopausal rats: role of silent information regulator 2 homolog 1 and transforming growth factor beta 1

BACKGROUND

Estrogen has a protective impact on acute kidney injury (AKI); moreover, reducing the daily intake of calories impedes developing diseases. The present study aimed to determine the effects of calorie restriction (CR) and time restriction (TR) diets on the expression of silent information regulator 2 homolog 1 (SIRT1), transforming growth factor beta 1 (TGF-β1), and other indicators in the presence and absence of ovaries in AKI female rats.

METHODS

The female rats were divided into two groups, ovariectomized (OVX) and sham, and were placed on CR and TR diets for eight weeks; afterward, AKI was induced by injecting glycerol, and kidney injury indicators and biochemical parameters were measured before and after AKI.

RESULTS

After AKI, the levels of urine albumin excretion rate, urea, and creatinine in serum, and TGF-β1 increased, while creatinine clearance and SIRT1 decreased in kidney tissue. CR improved kidney indicators and caused a reduction in TGF-β1 and an increase in SIRT1 in ovary-intact rats. Moreover, CR prevented total antioxidant capacity (TAC) decrease and malondialdehyde (MDA) increase resulting from AKI. Before AKI, an increase in body weight, fasting blood sugar (FBS), low-density lipoprotein (LDL), triglyceride (TG), and total cholesterol (TC), and a decrease in high-density lipoprotein (HDL) were observed in OVX rats compared to sham rats, but CR prevented these changes. The effects of TR were similar to those of CR in all indicators except for TGF-β1, SIRT1, urea, creatinine, and albumin.

CONCLUSION

The present study indicated that CR is more effective than TR in preventing AKI, probably by increasing SIRT1 and decreasing TGF-β1 in ovary-intact animals.

Intermittent Fasting in Youth: A Scoping Review

Intermittent fasting (IF) focuses on the timing of eating rather than diet quality or energy intake, with evidence supporting its effects on weight loss and cardiometabolic outcomes in adults. However, there is limited evidence for its efficacy in adolescents and emerging adults. To address this, a scoping review examined IF regimens in individuals aged 10 to 25, focusing on methodology, intervention parameters, outcomes, adherence, feasibility, and efficacy. The review included 39 studies with 731 participants aged 15 to 25. Methodologies varied, with 18 studies on time-restricted eating and others requiring caloric restriction. Primary outcomes included cardiometabolic risk factors (11/29), body composition (9/29), anthropometric measurements (8/29), and feasibility (2/29). Most studies reported significant weight loss. This review underscores IF's potential in treating obesity in this age group but highlights the need for rigorous studies with standardized frameworks for feasibility to ensure comparability and determine IF's practicality in this age group.

It's About Timing: Contrasting the Metabolic Effects of Early vs. Late Time-Restricted Eating in Humans

PURPOSE OF REVIEW

Time-restricted eating (TRE), a form of intermittent fasting, restricts feeding time across the day, imposing a daily 'eating window'. The time of day when the eating window occurs could result in differential metabolic effects. Here, we describe recent intervention studies in humans assessing the metabolic consequences of an early- (i.e., eating window starting in the early morning) vs. late (i.e., eating window starting after midday)-TRE protocol.

RECENT FINDINGS

Well-controlled studies indicate that both TRE protocols effectively reduce body weight and improve altered glucose metabolism, lipid profile, inflammation, or blood pressure levels. An early-TRE (e-TRE) might have a further positive impact on improving blood glucose, insulin levels, and insulin resistance. However, the studies directly assessing the metabolic consequences of an early- vs. late-TRE have shown dissimilar findings, and more well-controlled clinical trials are needed on the metabolic benefits of these two types of TRE. Evidence suggests that an e-TRE might have enhanced metabolic results, particularly regarding glucose homeostasis. More long-term studies, including larger sample sizes, are needed to assess the metabolic, circadian, and adherence benefits, together with socio-cultural acceptance of both TRE approaches.

Effects of Early and Late Time-Restricted Feeding on Parameters of Metabolic Health: An Explorative Literature Assessment

Chrono-nutrition (meal timing) aligns food consumption with one's circadian rhythm. The first meal (e.g., breakfast) likely promotes synchronization of peripheral circadian clocks, thereby supporting metabolic health. Time-restricted feeding (TRF) has been shown to reduce body weight (BW) and/or improve cardiovascular biomarkers. In this explorative literature assessment, 13 TRF randomized controlled trials (RCTs) were selected from PubMed and Scopus to evaluate the effects of early (eTRF: first meal before 10:30 a.m.) and late TRF (lTRF: first meal after 11:30 a.m.) on parameters of metabolic health. Although distinct variations in study design were evident between reports, TRF consistently decreased energy intake (EI) and BW, and improved insulin resistance as well as systolic blood pressure. eTRF seemed to have a greater beneficial effect than lTRF on insulin resistance (HOMA-IR). Importantly, most studies did not appear to consider chronotype in their evaluation, which may have underestimated TRF effects. TRF intervention may be a promising approach for risk reduction of human metabolic diseases. To conclusively determine benefits of TRF and identify clear differences between eTRF and lTRF, future studies should be longer-term (≥8 weeks) with well-defined (differences in) feeding windows, include participants chronotypically matching the intervention, and compare outcomes to those of control groups without any dietary limitations.

Effect of time restricted eating versus daily calorie restriction on sex hormones in males and females with obesity

This study examined the effects of time restricted eating (TRE) on sex hormones in males and females, versus daily calorie restriction (CR). Adults with obesity (n = 90) were randomized to 1 of 3 groups for 12-months: 8-h TRE (eating only between 12:00 to 8:00 pm, with no calorie counting); CR (25% energy restriction daily); or control. Body weight decreased (P < 0.01) in the TRE and CR groups, relative to controls, in males, premenopausal females, and postmenopausal females, by month 12. Total testosterone, dehydroepiandrosterone (DHEA), and sex hormone binding globulin (SHBG) levels did not change over time, or between groups, in males, premenopausal females, and postmenopausal females. Estradiol, estrone, and progesterone were only measured in postmenopausal females, and remained unchanged. These findings suggest that TRE produces significant weight loss but does not impact circulating sex hormone levels in males and females with obesity over 12 months, relative to CR and controls.

Trial registration

Clinicaltrials.gov , NCT04692532 .

Effects of 3 months of 10-h per-day time-restricted eating and 3 months of follow-up on bodyweight and cardiometabolic health in Danish individuals at high risk of type 2 diabetes: the RESET single-centre, parallel, superiority, open-label, randomised controlled trial

BACKGROUND

Time-restricted eating (TRE) has been suggested to be a simple, feasible, and effective dietary strategy for individuals with overweight or obesity. We aimed to investigate the effects of 3 months of 10-h per-day TRE and 3 months of follow-up on bodyweight and cardiometabolic risk factors in individuals at high risk of type 2 diabetes.

METHODS

This was a single-centre, parallel, superiority, open-label randomised controlled clinical trial conducted at Steno Diabetes Center Copenhagen (Denmark). The inclusion criteria were age 30-70 years with either overweight (ie, BMI ≥25 kg/m2) and concomitant prediabetes (ie, glycated haemoglobin [HbA1c] 39-47 mmol/mol) or obesity (ie, BMI ≥30 kg/m2) with or without prediabetes and a habitual self-reported eating window (eating and drinking [except for water]) of 12 h per day or more every day and of 14 h per day or more at least 1 day per week. Individuals were randomly assigned 1:1 to 3 months of habitual living (hereafter referred to as the control group) or TRE, which was a self-selected 10-h per-day eating window placed between 0600 h and 2000 h. Randomisation was done in blocks varying in size and was open for participants and research staff, but outcome assessors were masked during statistical analyses. The randomisation list was generated by an external statistician. The primary outcome was change in bodyweight, assessed after 3 months (12 weeks) of the intervention and after 3 months (13 weeks) of follow-up. Adverse events were reported and registered at study visits or if participants contacted study staff to report events between visits. This trial is registered on ClinicalTrials.gov (NCT03854656).

FINDINGS

Between March 12, 2019, and March 2, 2022, 100 participants (66 [66%] were female and 34 [34%] were male; median age 59 years [IQR 52-65]) were enrolled and randomly assigned (50 to each group). Of those 100, 46 (92%) in the TRE group and 46 (92%) in the control group completed the intervention period. After 3 months of the intervention, there was no difference in bodyweight between the TRE group and the control group (-0·8 kg, 95% CI -1·7 to 0·2; p=0·099). Being in the TRE group was not associated with a lower bodyweight compared with the control group after subsequent 3-month follow-up (-0·2 kg, -1·6 to 1·2). In the per-protocol analysis, participants who completed the intervention in the TRE group lost 1·0 kg (-1·9 to -0·0; p=0·040) bodyweight compared with the control group after 3 months of intervention, which was not maintained after the 3-month follow-up period (-0·4 kg, -1·8 to 1·0). During the trial and follow-up period, one participant in the TRE group reported a severe adverse event: development of a subcutaneous nodule and pain when the arm was in use. This side-effect was evaluated to be related to the trial procedures.

INTERPRETATION

3 months of 10-h per-day TRE did not lead to clinically relevant effects on bodyweight in middle-aged to older individuals at high risk of type 2 diabetes.

FUNDING

Novo Nordisk Foundation, Aalborg University, Helsefonden, and Innovation Fund Denmark.

Time-Restricted Eating and Bone Health: A Systematic Review with Meta-Analysis

Time-restricted eating (TRE) has emerged as a dietary strategy that restricts food consumption to a specific time window and is commonly applied to facilitate weight loss. The benefits of TRE on adipose tissue have been evidenced in human trials and animal models; however, its impact on bone tissue remains unclear. To systematically synthesize and examine the evidence on the impact of TRE on bone health (bone mineral content (BMC), bone mineral density (BMD), and bone turnover factors), PubMed, Scopus, Cochrane CENTRAL, and Web of Science databases were systematically explored from inception to 1 October 2023 searching for randomized controlled trials (RCTs) aimed at determining the effects of TRE on bone health in adults (≥18 years). The Cochrane Handbook and the PRISMA recommendations were followed. A total of seven RCTs involving 313 participants (19 to 68 years) were included, with an average length of 10.5 weeks (range: 4 to 24 weeks). Despite the significant weight loss reported in five out of seven studies when compared to the control, our meta-analysis showed no significant difference in BMD (g/cm2) between groups (MD = -0.009, 95% CI: -0.026 to 0.009, p = 0.328; I2 = 0%). BMC and bone turnover markers between TRE interventions and control conditions were not meta-analyzed because of scarcity of studies (less than five). Despite its short-term benefits on cardiometabolic health, TRE did not show detrimental effects on bone health outcomes compared to those in the control group. Nevertheless, caution should be taken when interpreting our results due to the scarcity of RCTs adequately powered to assess changes in bone outcomes.

Chrononutrition in the Prevention and Management of Metabolic Disorders: A Literature Review

BACKGROUND

The concept of time-restricted eating (TRE) or time-restricted feeding (TRF) promotes daily periods of feeding and fasting to determine whole-body physiology. Chronic misalignment of circadian rhythms or chrono-disruption is related to an increased risk of diverse metabolic disorders. The progression of non-communicable diseases seems to be affected by the timing of meals. As a result, intermittent fasting is a promising approach for their management. The aim of the present literature review is to examine and scrutinize the TRE protocols in the fields of prevention and management of metabolic disorders.

METHODS

This is a thorough literature review of the reported associations among circadian rhythm, metabolic disorders, diabetes mellitus, obesity, TRE, TRF, dietary habits, circadian disruption, cardiovascular diseases, atherosclerosis, and non-alcoholic fatty liver to find the already existing clinical studies from the last decade (2014-2024) in the most precise scientific online databases, using relevant specific keywords. Several inclusion and exclusion criteria were applied to scrutinize only longitudinal, cross-sectional, descriptive, and prospective clinical human studies.

RESULTS

The currently available clinical findings remain scarce and suggest that chrononutrition behaviors such as TRE or TRF may promote several metabolic benefits, mainly in body weight control and fat loss. Improvements in glucose levels and lipid profiles are currently quite controversial since some clinical studies show little or no effect. As far as liver diseases are concerned, the efficacy of intermittent fasting seems to be stronger in the management of non-alcoholic fatty liver disease due to body weight decline and fat loss.

CONCLUSIONS

Even if there has been a gradual increase in clinical studies in the last few years, providing promising perspectives, currently, there is no conclusive evidence for the role of chrononutrition in metabolic disorders. Future studies should be well-designed with longer duration and larger sample sizes. Moreover, it is important to examine the best timing of the eating window and its feasibility.