The circadian system maintains optimal biological functions at the appropriate time of day, and the disruption of this organization can contribute to the pathogenesis of cardiometabolic disorders. The timing of eating is a prominent external time cue that influences the circadian system. "Chrononutrition" is an emerging dimension of nutrition and active area of research that examines how timing-related aspects of eating and nutrition impact circadian rhythms, biological processes, and disease pathogenesis. There is evidence to support chrononutrition as a form of chronotherapy, such that optimizing the timing of eating may serve as an actionable strategy to improve cardiometabolic health. This report summarizes key information from the National Heart, Lung, and Blood Institute's virtual workshop entitled "Chrononutrition: Elucidating the Role of Circadian Biology and Meal Timing in Cardiometabolic Health," which convened on May 2 to 3, 2023, to review current literature and identify critical knowledge gaps and research opportunities. The speakers presented evidence highlighting the impact on cardiometabolic health of earlier and shorter eating windows and more consistent day-to-day eating patterns. The multidimensionality of chrononutrition was a common theme, as it encompasses multiple facets of eating along with the timing of other behaviors including sleep and physical activity. Advancing the emerging field of chrononutrition will require: (1) standardization of terminology and metrics; (2) scalable and precise tools for real-world settings; (3) consideration of individual differences that may act as effect modifiers; and (4) deeper understanding of social, behavioral, and cultural influences. Ultimately, there is great potential for circadian-based dietary interventions to improve cardiometabolic health.

Different intermittent fasting (IF) protocols have been proven to be efficient in improving cardiometabolic markers, but further research is needed to examine whether or not combining IF regimens plus physical exercise is superior to control diets (ie, nonfasting eating) plus physical exercise in this setting.

The aim of this study was to determine whether or not combining IF plus exercise interventions is more favorable than a control diet plus exercise for improving cardiometabolic health outcomes.

PubMed, Scopus, and Web of Science were comprehensively searched until April 2023.

Electronic databases were searched for clinical trials that determined the effect of IF plus exercise vs a control diet plus exercise on body weight, lipid profile (high-density lipoprotein [HDL], low-density lipoprotein [LDL], triglycerides, and total cholesterol), and systolic and diastolic blood pressure (SBP and DBP, respectively). Analyses were conducted for IF plus exercise vs a nonfasting diet plus exercise to calculate weighted mean differences (WMDs).

The meta-analysis included a total of 14 studies, with a total sample of 360 adults with or without obesity. The duration ranged from 4 to 52 weeks. IF plus exercise decreased body weight (WMD = -1.83 kg; P = 0.001), LDL (WMD = -5.35 mg/dL; P = 0.03), and SBP (WMD = -2.99 mm Hg; P = 0.003) significantly more than a control diet plus exercise. HDL (WMD = 1.57 mg/dL; P = 0.4) and total cholesterol (WMD = -2.24 mg/dL; P = 0.3) did not change significantly for IF plus exercise vs a control diet plus exercise, but there was a trend for reducing triglycerides (WMD = -13.13 mg/dL; P = 0.07) and DBP (WMD = 2.13 mm Hg; P = 0.05), which shows clinical magnitude.

IF plus exercise improved some cardiometabolic outcomes (body weight, blood pressure, and lipid profile) compared with a control diet plus exercise.

PROSPERO registration no. CRD42023423878.

Intermittent fasting (IF) holds promise for enhancing metabolic health. However, the optimum IF forms and their superiority over continuous energy restriction (CER) remain unclear due to disconnected findings.

We systematically searched PubMed, Embase, and the Cochrane databases for meta-analyses of randomized controlled trials (RCTs) investigating the association between IF and metabolic health outcomes. Subsequently, we performed an umbrella review and network meta-analysis (NMA) to evaluate the efficacy of different forms of IF (time-restricted eating (TRE), alternate-day fasting (ADF), and 5:2 diet (regular eating for 5 days and energy restriction for 2 days per week)) compared to CER and usual diets on metabolic health outcomes. To assess the certainty of both direct and indirect estimates, we employed the Confidence in Network Meta-Analysis (CINeMA) approach. Additionally, we calculated the surface under the cumulative ranking curve (SUCRA) for each dietary strategy to determine their ranking in terms of metabolic health benefits.

Ten of the best and non-redundant meta-analysis studies, involving 153 original studies and 9846 participants, were included. When considering direct evidence only, all IF forms significantly reduced body weight compared to usual diets. In NMA incorporating indirect evidence, all IF regimens also significantly reduced body weight compared to usual diets. In the SUCRA of NMA, IF ranked higher than usual diets or CER in 85.4% and 56.1% of the outcomes, respectively. ADF had the highest overall ranking for improving metabolic health (ranked first: 64.3%, ranked second: 14.3%).

Overall, all IF forms demonstrate potentials to improve metabolic health, with ADF appearing to produce better outcomes across investigated outcomes. Further high-quality trials are warranted to confirm the (relative) efficacy of IF on metabolic health.

PROSPERO (record no: CRD42022302690).

Intermittent fasting (IF), characterized by alternating periods of fasting and unrestricted eating, typically within an 8-hour window or less each day, has gained significant attention as a possible dietary approach. While it is recognized for its metabolic advantages, like weight loss and enhanced glucose and insulin sensitivity, its effect on cardiovascular health remains a topic of mixed opinions. Recent findings suggest a potential downside, with reports indicating a concerning association: a 91 % higher risk of cardiovascular disease (CVD) mortality compared to eating spread across a 12- to 16-hour period. Despite this alarming statistic, the evidence cannot establish a causal link. The impact of IF on CVD is still insufficiently understood, with benefits sometimes exaggerated and risks downplayed in popular discourse. This scoping review aims to consolidate the current evidence, addressing unresolved questions about the benefits and risks of IF, particularly its association with CVD risks and mortality. The goal is to provide a balanced perspective on the potential health implications of IF, emphasizing the need for further research to clarify its long-term effects on cardiovascular health.

There is a need to investigate the effect of lifestyle modifications on cardiometabolic health-related issues that occur during menopause. The aim of this study was to compare the effect of resistance and endurance circuit training program alone (exercise group, n = 34) with the effect of time-restricted eating (16:8) combined with a training program (combination group, n = 28) on cardiometabolic health in 62 menopausal women (aged 51.3 ± 4.69 years). Testing was conducted before and after a 12-week period and included an assessment of body composition, glycemic control, lipid panel, blood pressure, and anthropometric measurements. Decreases in body mass index and systolic blood pressure were significantly greater in the combination group than in the exercise group (F(1,60) = 4.482, p = 0.038, η2 = 0.07; F(1,57) = 5.215, p = 0.026, η2 = 0.08, respectively, indicating moderate effects). There were significant decreases in fat mass (p = 0.001, r = 0.654), glucose level (p = 0.017, r = 0.459), insulin level (p = 0.013, r = 0.467), homeostatic model assessment for insulin resistance (p = 0.009, r = 0.499), waist circumference (p = 0.002, r = 0.596), and waist-to-height ratio (p = 0.003, r = 0.588) (indicating moderate effect) in the combination group, while there were no significant changes in the exercise group. There were no changes in lipid panel indicators in either group. This is the first study to investigate the effect of time-restricted eating combined with exercise in menopausal women. The results of the study provide evidence that the combination of time-restricted eating and exercise leads to a greater body mass index reduction than exercise alone in menopausal women.Trial registration: ClinicalTrials.gov, NCT06138015 registered 18 November 2023-Retrospectively registered, https://clinicaltrials.gov/study/NCT06138015 .

To perform a meta-analysis to investigate the effects of intermittent fasting (IF), as compared with either a control diet (CON) and/or calorie restriction (CR), on body composition and cardiometabolic health in individuals with prediabetes and type 2 diabetes (T2D).

PubMed, Web of Science, and Scopus were searched from their inception to March 2024 to identify original randomized trials with parallel or crossover designs that studied the effects of IF on body composition and cardiometabolic health. Weighted mean differences (WMDs) or standardized mean differences with 95% confidence intervals (CIs) were calculated using random-effects models.

Overall, 14 studies involving 1101 adults with prediabetes or T2D were included in the meta-analysis. IF decreased body weight (WMD -4.56 kg [95% CI -6.23 to -2.83]; p = 0.001), body mass index (BMI; WMD -1.99 kg.m2 [95% CI -2.74 to -1.23]; p = 0.001), glycated haemoglobin (HbA1c; WMD -0.81% [95% CI -1.24 to -0.38]; p = 0.001), fasting glucose (WMD -0.36 mmol/L [95% CI -0.63 to -0.09]; p = 0.008), total cholesterol (WMD -0.31 mmol/L [95% CI -0.60 to -0.02]; p = 0.03) and triglycerides (WMD -0.14 mmol/L [95% CI -0.27 to -0.01]; p = 0.02), but did not significantly decrease fat mass, insulin, low-densitiy lipoprotein, high-density lipoprotein, or blood pressure as compared with CON. Furthermore, IF decreased body weight (WMD -1.14 kg [95% CI -1.69 to -0.60]; p = 0.001) and BMI (WMD -0.43 kg.m2 [95% CI -0.58 to -0.27]; p = 0.001), but did not significantly affect fat mass, lean body mass, visceral fat, insulin, HbA1c, lipid profiles or blood pressure.

Intermittent fasting is effective for weight loss and specific cardiometabolic health markers in individuals with prediabetes or T2D. Additionally, IF is associated with a reduction in body weight and BMI compared to CR, without effects on glycaemic markers, lipid profiles or blood pressure.

We hereby comment on the systematic review "Effects of Intermittent Fasting on Regulation of Metabolic Homeostasis: A Systematic Review and Meta-Analysis in Health and Metabolic-Related Disorders" by Silva et al [...].

Intermittent fasting (IF) has been indicated as a valuable alternative to the classical caloric restriction dietary regimen for lowering body weight and preventing obesity-related complications, such as metabolic syndrome and type II diabetes. However, is it effective? In this review article, we analyzed over 50 clinical studies in which IF, conducted by alternate day fasting (ADF) or time-restricted feeding (TRF), was compared with the caloric restriction approach. We evaluated the different roles of IF in treating and preventing human disorders such as metabolic syndrome, type II diabetes, and some types of cancer, as well as the usefulness of IF in reducing body weight and cardiovascular risk factors such as hypertension. Furthermore, we explored the cellular pathways targeted by IF to exert their beneficial effects by activating effector proteins that modulate cell functions and resistance to oxidative stress. In contrast, we investigated concerns regarding human health related to the adoption of IF dietary regimens, highlighting the profound debate surrounding weight loss regimens. We examined and compared several clinical trials to formulate an updated concept regarding IF and its therapeutic potential.

The digital health field is experiencing substantial growth due to its potential for sustained and longitudinal deployment. In turn, this may drive improved monitoring and intervention as catalysts for behavioral change compared to traditional point-of-care practices. In particular, the increase in incidence of population health challenges such as diabetes, heart disease, fatty liver disease, and other disorders coupled with rising healthcare costs have emphasized the importance of exploring technical, economics, and implementation considerations, among others in the decentralization of health and healthcare innovations. Both healthy individuals and patients stand to benefit from continued technical advances and studies in these domains. To address these points, this study reports a N-of-1 study comprised of sustained regimens of intermittent fasting, fitness (strength and cardiovascular training), and high protein, low carbohydrate diet and parallel monitoring. These regimens were paired with serial blood ketone, blood glucose (wearable and finger stick) and blood pressure readings, as well as body weight measurements using a collection of devices. Collectively this suite of platforms and approaches were used to monitor metabolic switching from glucose to ketones as energy sources-a process associated with potential cardio- and neuroprotective functions. In addition to longitudinal biomarker dynamics, this work discusses user perspectives on the potential role of harnessing digital devices to these dynamics as potential gamification factors, as well as considerations for the role of biomarker monitoring in health regimen development, user stratification, and potentially informing downstream population-scale studies to address metabolic disease, healthy aging and longevity, among other indications.

The purpose of this review is to synthesize results from studies examining the association between time-of-day for eating, exercise, and sleep with blood pressure (BP) in adults with elevated BP or hypertension. Six databases were searched for relevant publications from which 789 were identified. Ten studies met inclusion criteria. Four studies examined time-of-day for eating, five examined time-of-day for exercise, and one examined time-of-day for sleep and their associations with BP. Results suggested that later time-of-day for eating ( n  = 2/4) and later sleep mid-point ( n  = 1/1) were significantly related to higher BP in multivariable models, whereas morning ( n  = 3/5) and evening ( n  = 4/5) exercise were associated with significantly lower BP. Although this small body of work is limited by a lack of prospective, randomized controlled study designs and underutilization of 24 h ambulatory BP assessment, these results provide preliminary, hypothesis-generating support for the independent role of time-of-day for eating, exercise, and sleep with lower BP.

In recent years, intermittent fasting (IF) and its numerous modifications have been increasingly suggested as a promising therapy for age-related problems and a non-pharmacological strategy to extend lifespan. Despite the great variability in feeding schedules that we describe in the current work, underlying physiological processes are the same and include a periodic switch from glucose metabolism (generated by glycogenolysis) to fatty acids and fatty acid-derived ketones. Many of the beneficial effects of IF appear to be mediated by optimization of energy utilization. Findings to date from both human and animal experiments indicate that fasting improves physiological function, enhances performance, and slows aging and disease processes. In this review, we discuss some of the remarkable discoveries about the beneficial effects of IF on metabolism, endocrine and cardiovascular systems, cancer prevention, brain health, neurodegeneration and aging. Experimental studies on rodent models and human investigations are summarized to compare the outcomes and underlying mechanisms of IF. Metabolic and cellular responses triggered by IF could help to achieve the aim of preventing disease, and maximizing healthspan and longevity with minimal side effects.

Time-restricted eating (TRE) is an effective way to lose weight and improve metabolic health in animals. Yet whether and how these benefits apply to humans is unclear. This systematic review and meta-analysis examined the effect of TRE in people with overweight and obesity statuses. The results showed that TRE led to modest weight loss, lower waist circumference and energy deficits. TRE also improved body mass index, fat mass, lean body mass, systolic blood pressure, fasting glucose levels, fasting insulin levels, and HbA1c%. Subgroup analysis demonstrated more health improvements in the TRE group than the control group under the ad libitum intake condition than in the energy-prescribed condition. Eating time-of-day advantages were only seen when there was considerable energy reduction in the TRE group than the control group (ad libitum condition), implying that the benefits of TRE were primarily due to energy deficit, followed by alignment with eating time of day.

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

Exercise training (Ex) and intermittent fasting (IF) are effective for improving body composition and cardiometabolic health overweight and obese adults, but whether combining Ex and IF induces additive or synergistic effects is less well established. We therefore, performed a systematic review and meta-analysis to compare the combined versus independent effects of Ex and IF on body composition and cardiometabolic health in adults.

An electronic search was conducted in three main online databases including PubMed, Web of Science, and Scopus, from inception to March 9, 2023 for studies involving Ex plus IF trials versus standalone Ex and/or IF interventions in adults. Interventions had a duration of ≥ 2 weeks. Standardized (SMD) or weighted mean differences (WMD) and 95% confidence intervals were calculated in order to compare effects on body weight, body mass index (BMI), body fat lean body mass (LBM), visceral fat, and waist circumference. For cardiometabolic health, outcomes included fasting glucose, insulin, total cholesterol (TC), low-density lipoprotein cholesterol (LDL), triglycerides (TG), high-density lipoprotein cholesterol (HDL), systolic (SBP) and diastolic (DBP) blood pressure, and VO2max/peak.

Ex plus IF decreased body weight [WMD: -3.03 kg (95% CI: -3.44 to -2.61), p = 0.001], BMI [WMD: -1.12 kg.m2 (95% CI: -1.28 to -0.95), p = 0.001], body fat [SMD: -0.72 (95% CI: -1.23 to -0.21), p = 0.005], visceral fat [SMD: -0.34 (95% CI: -0.63 to -0.05), p = 0.01], and waist circumference [WMD: -2.63 cm (95% CI: -4.16 to -1.11), p = 0.001] more than Ex alone. However, changes in body composition and cardiometabolic health markers were not significantly different for Ex plus IF when compared with IF alone, with the exception of VO2max/peak [SMD: 0.55 (95% CI: 0.14 to 0.97), p = 0.009].

We demonstrate that a combination of Ex and IF produces superior changes in body composition, but not in markers of cardiometabolic health when compared with Ex or IF alone. Ex plus IF could therefore be effective for weight and fat loss but has no additive or synergistic effects for other cardiometabolic health markers.

Time-restricted eating (TRE) is a dietary approach that limits eating to a set number of hours per day. Human studies on the effects of TRE intervention on cardiometabolic health have been contradictory. Heterogeneity in subjects and TRE interventions have led to inconsistency in results. Furthermore, the impact of the duration of eating/fasting in the TRE approach has yet to be fully explored.

To analyze the existing literature on the effects of TRE with different eating durations on anthropometrics and cardiometabolic health markers in adults with excessive weight and obesity-related metabolic diseases.

We reviewed a series of prominent scientific databases, including Medline, Scopus, Web of Science, Academic Search Complete, and Cochrane Library articles to identify published clinical trials on daily TRE in adults with excessive weight and obesity-related metabolic diseases. Randomized controlled trials were assessed for methodological rigor and risk of bias using version 2 of the Cochrane risk-of-bias tool for randomized trials (RoB-2). Outcomes of interest include body weight, waist circumference, fat mass, lean body mass, fasting glucose, insulin, HbA1c, homeostasis model assessment for insulin resistance (HOMA-IR), lipid profiles, C-reactive protein, blood pressure, and heart rate.

Fifteen studies were included in our systematic review. TRE significantly reduces body weight, waist circumference, fat mass, lean body mass, blood glucose, insulin, and triglyceride. However, no significant changes were observed in HbA1c, HOMA-IR, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, heart rate, systolic and diastolic blood pressure. Furthermore, subgroup analyses based on the duration of the eating window revealed significant variation in the effects of TRE intervention depending on the length of the eating window.

TRE is a promising chrononutrition-based dietary approach for improving anthropometric and cardiometabolic health. However, further clinical trials are needed to determine the optimal eating duration in TRE intervention for cardiovascular disease prevention.

Intermittent fasting (IF) is an emerging dietetic intervention that has been associated with improved metabolic parameters. Nowadays, the most common IF protocols are Alternate-Day Fasting (ADF) and Time-Restricted Fasting (TRF), but in this review and meta-analysis we have also considered Religious Fasting (RF), which is similar to TRF but against the circadian rhythm. The available studies usually include the analysis of a single specific IF protocol on different metabolic outcomes. Herein, we decided to go further and to conduct a systematic review and meta-analysis on the advantages of different IF protocols for metabolic homeostasis in individuals with different metabolic status, such as with obesity, diabetes mellitus type 2 (T2D) and metabolic syndrome (MetS). Systematic searches (PubMed, Scopus, Trip Database, Web of Knowledge and Embase, published before June 2022) of original articles in peer-review scientific journals focusing on IF and body composition outcomes were performed. Sixty-four reports met the eligibility criteria for the qualitative analysis and forty-seven for the quantitative analysis. Herein, we showed that ADF protocols promoted the major beneficial effects in the improvement of dysregulated metabolic conditions in comparison with TRF and RF protocols. Furthermore, obese and MetS individuals are the most benefited with the introduction of these interventions, through the improvement of adiposity, lipid homeostasis and blood pressure. For T2D individuals, IF impact was more limited, but associated with their major metabolic dysfunctions-insulin homeostasis. Importantly, through the integrated analysis of distinct metabolic-related diseases, we showed that IF seems to differently impact metabolic homeostasis depending on an individual's basal health status and type of metabolic disease.