Effects of Time-Restricted Feeding and Ramadan Fasting on Body Weight, Body Composition, Glucose Responses, and Insulin Resistance: A Systematic Review of Randomized Controlled Trials

The effectiveness of mobile app usage in facilitating weight loss: An observational study

Aim

With increasing rates of global obesity and associated health issues, there is an ever-increasing need for weight management solutions to be more accessible. Mobile applications offer accessible support systems and have the potential to offer a viable and effective weight management solution as an alternative to traditional healthcare models.

Objective

To evaluate the effectiveness of the SIMPLE mobile application for time-restricted eating in achieving weight loss (WL).

Methods

User data were analyzed between January 2021 and January 2023. In-app activity was calculated as the proportion of active days over 12, 26 and 52 weeks. A day is considered active if it contains at least one in-app action (e.g., logging weight, food, fasting, or physical activity). Users were categorized into four in-app activity levels: inactive (in-app activity <33%), medium activity (33%-66%), high activity (66%-99%), and maximal activity (100%). Weight change among in-app activity groups was assessed at 12, 26, and 52 weeks.

Results

Out of 53,482 users, a positive association was found between the use of the SIMPLE app and WL. Active app users lost more weight than their less active counterparts. Active users had a median WL of 4.20%, 5.04%, and 3.86% at 12, 26, and 52 weeks, respectively. A larger percentage of active users-up to 50.26%-achieved clinically significant WL (≥5%) when compared to inactive users. A dose-response relationship between WL and app usage was found after adjusting for gender, age, and initial Body Mass Index; a 10% increase in app activity correlated with increased WL by 0.43, 0.66 and 0.69 kg at 12, 26, and 52 weeks, respectively.

Conclusions

The study demonstrates that the SIMPLE app enables effective WL directly associated with the level of app engagement. Mobile health applications offer an accessible and effective weight management solution and should be considered when supporting adults to lose weight.

Scoping review: Exploring the relationship between chrononutrition and glycemic responses in the adult population

Chrononutrition, an emerging body of evidence on the relationship between biological rhythms and metabolism, has been established to be associated with glycemic responses. However, the available evidence is inconsistent, due to protocol variations. Therefore, this review aims to summarize the findings on chrononutrition characteristics and their association with glycemic responses among adults. Systematic searches were conducted across six databases (PubMed, EBSCO Host, ProQuest Central, MEDLINE & Ovid, Scopus and Web of Science) to identify all relevant studies published from January 2012. Two reviewers independently screened the abstracts and full-text articles based on the inclusion and exclusion criteria. Details about population characteristics, study methods and key findings were extracted following the PRISMA-ScR guideline. The quality of selected studies was evaluated using the mixed methods appraisal tool. The searchers identified 49 studies eligible for analysis. The results showed that meal timing, particularly night-time eating and snacking were associated with glycemic responses. Regarding meal regularity, skipping breakfast may affect glycemic responses, but no clear conclusion was drawn about its effect on insulin. The association between meal frequency and glycemic responses was inconclusive. Night fasting duration and restricted eating window are potentially associated with glycemic responses. The current review extensively investigates the association between chrononutrition factors and glycemic responses in adults. However, more prospective cohort and interventional studies are needed to better understand this causal-effect relationship.

Eating Patterns, Chronotypes, and Their Relationship with Metabolic Health in the Early Postpartum Period in Women after Gestational Diabetes Mellitus

Observational studies have shown a relationship between eating patterns and chronotypes with metabolic health in the general population and in healthy pregnancies. Data are lacking in the postpartum period, which is characterized by an externally driven misalignment of sleep and food intake. We investigated the associations between eating patterns, chronotypes, and metabolic health in the early postpartum period in women who had gestational diabetes mellitus (GDM). We prospectively included 313 women who completed their 6-8 weeks postpartum visit between January 2021 and March 2023 at the Lausanne University Hospital. Women filled questionnaires on the timing of food intake, sleep (a shortened Pittsburgh Sleep Quality Questionnaire), and the chronotype (the Morningness-Eveningness Questionnaire) and underwent HbA1c and fasting plasma glucose measurements. After adjustments for weight, sleep quality, or breastfeeding, the later timing of the first and last food intake were associated with higher fasting plasma glucose and HbA1c levels 6-8 weeks postpartum (all p ≤ 0.046). A higher number of breakfasts per week and longer eating durations were associated with lower fasting plasma glucose levels (all p ≤ 0.028). The chronotype was not associated with metabolic health outcomes. Eating patterns, but not the chronotype, were associated with worsened metabolic health in the early postpartum period in women with previous GDM.

The effect of observing religious or faith-based fasting on cardiovascular disease risk factors: A systematic review and meta-analysis

AIMS

Cardiovascular diseases (CVD) are the leading cause of death worldwide. Fasting is common in many religions and is associated with health benefits. This systematic review to compares the impact of different religious fasting practices, on risk of cardiometabolic diseases.

DATA SYNTHESIS

The search covered five databases following PRISMA guidelines to identify papers published in English from inception to March 2023 (updated January 2024). Inclusion criteria were healthy adults in observational studies, who engaged in religious fasting practices, studies were included where data on matched non-fasting individuals was available. Outcomes were systolic and diastolic blood pressure, body mass index (BMI), triglycerides, total cholesterol (TC), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc), and fasting plasma glucose levels. A meta-analysis was conducted, and the review was registered (CRD42022352197). Fourteen studies were met the inclusion criteria with ten studies data being suitable for meta-analysis, reporting on 755 adults participating in fasting practices and 661 non-fasting controls. Religious fasting was associated with a reduction in BMI (-0.40 kg/m2, 95% CI [-0.70, -0.10], p < 0.01). Observance of Ramadan fasting was associated with decreased systolic blood pressure (-3.83  mmHg, 95% CI [-7.44, -0.23], p = 0.04). The observance of Orthodox Christian fasting was associated with a reduction in TC (-0.52 mmoL/l, 95%CI [-0.64, -0.39], p < 0.01). No difference was found for the other outcomes.

CONCLUSION

This review found religious fasting practices which were associated with a reduction in some biomarkers of cardiometabolic diseases risk. Further research on other fasting practices is needed due to limited data.

Time-restricted feeding can increase food-related impulsivity: a randomized controlled trial

OBJECTIVES

Although an increasing number of studies show that time-restricted feeding may improve metabolic health, studies examining the behavioral effects of this eating pattern are limited. This study examined the effect of time-restricted feeding on impulsivity in adults.

METHODS

Thirty adults aged 25-41 years participated in this randomized controlled trial. The intervention group followed time-restricted feeding for 4 weeks and there was no energy restriction in the intervention group (n = 15) or control group (n = 15). Impulsivity was assessed before and after the intervention with the Barratt Impulsiveness Scale and the Go/NoGo task.

RESULTS

The compliance rate (the percentage of days when participants had a feeding time of ≤ 8 hours/day) of the intervention group to the time-restricted feeding pattern was 92.38 ± 4.24%. The Barratt Impulsiveness Scale-11 total score of the intervention group increased from 55.53 ± 6.37 to 59.47 ± 7.67 (p = 0.02). During the Go/NoGo task, an indicator of inhibitory control, the reaction time to food and non-food stimuli was significantly shortened in the intervention group (respectively; p = 0.009, p = 0.01). In the control group, no significant change was detected in impulsivity determined by the BIS-11 or Go/NoGo task.

DISCUSSION

This study showed that although time-restricted feeding may reduce body weight, it can lead to increased impulsivity and impaired inhibitory control.Trial registration: ClinicalTrials.gov identifier: NCT04960969.

Circadian alignment of food intake and glycaemic control by time-restricted eating: A systematic review and meta-analysis

Daily rhythms of metabolic function are supported by molecular circadian clock systems that are strongly regulated by feeding and fasting. Intermittent fasting diets have been associated with weight loss and improved metabolism. However, the effects of time-restricted eating (TRE) on glycemic parameters are still under debate. In this review, we aim to systematically analyze the effects of TRE on glycemic parameters. We searched on PubMed, EMBASE, and the Cochrane Library for controlled studies in which subjects followed TRE for at least 4 weeks. 20 studies were included in the qualitative systematic review, and 18 studies (n = 1169 subjects) were included in the meta-analysis. Overall, TRE had no significant effect on fasting glucose (Hedges's g = -0.08; 95% CI:-0.31,0.16; p = 0.52), but it did reduce HbA1c levels (Hedges's g = -0.27; 95% CI: -0.47, -0.06; p = 0.01). TRE significantly reduced fasting insulin (Hedges's g = -0.40; 95% CI: -0.73,-0.08; p = 0.01) and showed a tendency to decrease HOMA-IR (Hedges's g = -0.32; 95% CI:-0.66,0.02; p = 0.06). Interestingly, a cumulative analysis showed that the beneficial effects of TRE regarding glucose levels were less apparent as studies with later TRE windows (lTRE) were being included. Indeed, a subgroup analysis of the early TRE (eTRE) studies revealed that fasting glucose was significantly reduced by eTRE (Hedges's g = -0.38; 95% CI:-0.62, -0.14; p < 0.01). Our meta-analysis suggests that TRE can reduce HbA1c and insulin levels, and that timing of food intake is a crucial factor in the metabolic benefit of TRE, as only eTRE is capable of reducing fasting glucose levels in subjects with overweight or obesity.PROSPERO registration number CRD42023405946.

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.

Effect of Aerobic Exercise and Time-Restricted Feeding on Metabolic Markers and Circadian Rhythm in Mice Fed with the High-Fat Diet

SCOPE

Diet and exercise are significant players in obesity and metabolic diseases. Time-restricted feeding (tRF) has been shown to improve metabolic responses by regulating circadian clocks but whether it acts synergically with exercise remains unknown. It is hypothesized that forced exercise alone or combined with tRF alleviates obesity and its metabolic complications.

METHODS AND RESULTS

Male C57bl6 mice are fed with high-fat or a control diet for 12 weeks either ad libitum or tRF for 10 h during their active period. High-fat diet (HFD)-fed mice are divided into exercise (treadmill for 1 h at 12 m min-1 alternate days for 9 weeks and 16 m min-1 daily for the following 3 weeks) and non-exercise groups. tRF and tRF-Ex significantly decreased body weight, food intake, and plasma lipids, and improved glucose tolerance. However, exercise reduced only body weight and plasma lipids. tRF and tRF-Ex significantly downregulated Fasn, Hmgcr, and Srebp1c, while exercise only Hmgcr. HFD feeding disrupted clock genes, but exercise, tRF, and tRF-Ex coordinated the circadian clock genes Bmal1, Per2, and Rev-Erbα in the liver, adipose tissue, and skeletal muscles.

CONCLUSION

HFD feeding disrupted clock genes in the peripheral organs while exercise, tRF, and their combination restored clock genes and improved metabolic consequences induced by high-fat diet feeding.

Association of Christian Orthodox Fasting with Sociodemographic, Anthropometric and Lifestyle Factors and Serum Biochemical Indices: A Cross-Sectional Study on Patients with Metabolic Diseases

Christian Orthodox fasting, a type of time-restricted diet, which presents some similarities to the Mediterranean Diet, also including certain similarities with periodic vegetarianism or other time-restricted diets (e.g., intermittent diet and Ramadan fasting), may cumulatively be related to the same or even better beneficial healthy effects as these well-recognized dietary patterns. The present study aimed to explore the potential beneficial impact of Christian Orthodox fasting in patients with metabolic disorders, such as diabetes mellitus type 2, excessive obesity, hypothyroidism and osteoporosis. This was a cross-sectional study, including 135 patients with metabolic disorders (67 fasters and 68 non-fasters). The enrolled fasters had adapted Christian Orthodox fasting recommendations for at least twelve consecutive years or even from childhood. Relevant questionnaires were used to record sociodemographic, anthropometric and lifestyle data of the study population through face-to-face interviews between the enrolled individuals and qualified personnel during a non-fasting period. Christian Orthodox fasting patients showed a significantly and independently lower prevalence of overweight/obesity and abdominal obesity, which is highly associated with cardiometabolic disease risks, as well as a significantly and independently lower incidence of hypertension, including separately lower systolic and diastolic pressure, than non-fasting patients. Fasters also had a significantly and independently increased prevalence of an advanced educational level and no smoking history, as well as a lower incidence of sedentary behavior, and a trend of a correlation with reduced c-reactive protein (CRP), an indicator of inflammation, compared to non-fasters. Fasters also exhibited higher serum albumin and high-density lipoprotein (HDL) levels, as well as lower glucose levels, than non-fasters. This is one of the few cross-sectional studies demonstrating that Christian Orthodox fasting may promote metabolic health by improving several aspects of metabolic disorders, being associated with specific sociodemographic, anthropometric and lifestyle factors. Further studies conducted on larger sample sizes from different countries and different ethnicities that include Christian Orthodox fasters are recommended to evaluate the impact of long-term religious fasting effects on human health, either as a preventative factor reducing the risk of chronic diseases and especially cardiometabolic disorders or as a nutritional intervention to ameliorate symptom severity.

Differences in Dietary Intake, Eating Occasion Timings and Eating Windows between Chronotypes in Adults Living with Type 2 Diabetes Mellitus

Chronotype studies investigating dietary intake, eating occasions (EO) and eating windows (EW) are sparse in people with type 2 Diabetes mellitus (T2DM). This analysis reports data from the CODEC study. The Morningness-Eveningness questionnaire (MEQ) assessed chronotype preference. Diet diaries assessed dietary intake and temporal distribution. Regression analysis assessed whether dietary intake, EW, or EO differed by chronotype. 411 participants were included in this analysis. There were no differences in energy, macronutrient intake or EW between chronotypes. Compared to evening chronotypes, morning and intermediate chronotypes consumed 36.8 (95% CI: 11.1, 62.5) and 20.9 (95% CI: -2.1, 44.1) fewer milligrams of caffeine per day, respectively. Evening chronotypes woke up over an hour and a half later than morning (01:36 95% CI: 01:09, 02:03) and over half an hour later than intermediate chronotypes (00:45 95% CI: 00:21; 01:09. Evening chronotypes went to sleep over an hour and a half later than morning (01:48 95% CI: 01:23; 02:13) and an hour later than intermediate chronotypes (01:07 95% CI: 00:45; 01:30). Evening chronotypes' EOs and last caffeine intake occurred later but relative to their sleep timings. Future research should investigate the impact of chronotype and dietary temporal distribution on glucose control to optimise T2DM interventions.

Keto Menu-Effect of Ketogenic Menu and Intermittent Fasting on the Biochemical Markers and Body Composition in a Physically Active Man-A Controlled Case Study

The combination of ketogenic diet (KD) with intermittent fasting (IF) has, for years, aroused a great interest in the scientific world and among healthy lifestyle enthusiasts. Its importance is even greater when the study subjects are physically active individuals. The aim of the study was a determination of the effect of strict calculated ketogenic menu combined with IF and with caloric deficit on the selected biochemical markers and body composition in a 23-year-old man performing strength training. At the same time, we decided to conduct the first so-deeply investigated and controlled case study in this respect. The study protocol included a 13-week-long ketogenic diet with intermittent fasting (of delayed time-restricted eating 16:8 type) and caloric deficit. A detailed menu was designed and was used by the man throughout the whole study duration. A number of blood tests were performed before and after the implemented dietary intervention. Additionally, body composition was determined weekly and the concentrations of glucose and ketone bodies, as well as pulse rate and arterial pressure, were measured daily. The most important changes noted included a significant increase in testosterone and vitamin D concentrations and significant reduction in the HOMA-IR index and concentrations of hepatic enzymes, insulin, glucose, iron, urea, and free triiodothyronine (FT3). Moreover, a significant improvement of body composition occurred (the ratio of total body mass to the adipose and muscular tissue and water mass improved). Favourable changes were also noted in heart rate and arterial pressure values. In view of that, the KD with IF and caloric deficit exerted favourable effects on most biochemical parameters and on body composition and caused an almost twofold increase in serum testosterone concentration.

Effects of time-restricted eating with different eating duration on anthropometrics and cardiometabolic health: A systematic review and meta-analysis

BACKGROUND

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.

AIM

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Non-Classical Aspects of Obesity Pathogenesis and Their Relative Clinical Importance for Obesity Treatment

Obesity is a chronic disease and a major public health problem due to its association with non-communicable diseases and all-cause mortality. An increased energy intake and decreased physical activity have been long recognized as the classical parameters that contribute to the development of obesity. However, several other, non-classical factors have also been associated with obesity through various complex mechanisms. Some of them are diet related, such as diet quality, dietary habits and speed of eating. Other factors are non-dietary, such as endocrine-disrupting chemicals, sleep quality and quantity, psychotropic medications and light at night. The scope of the present narrative review is to address these non-classical factors that are implicated in the pathogenesis of obesity, to clarify their potential role in the management of obesity and, where possible, to provide some practical clinical recommendations.

Timing Is Important-Management of Metabolic Syndrome According to the Circadian Rhythm

Physiological processes occur in accordance with a rhythm regulated by the endogenous biological clock. This clock is programmed at the molecular level and synchronized with the daily light-dark cycle, as well as activities such as feeding, exercise, and social interactions. It consists of the core clock genes, Circadian Locomotor Output Cycles Protein Kaput (CLOCK) and Brain and Muscle Arnt-Like protein 1 (BMAL1), and their products, the period (PER) and cryptochrome (CRY) proteins, as well as an interlocked feedback loop which includes reverse-strand avian erythroblastic leukemia (ERBA) oncogene receptors (REV-ERBs) and retinoic acid-related orphan receptors (RORs). These genes are involved in the regulation of metabolic pathways and hormone release. Therefore, circadian rhythm disruption leads to development of metabolic syndrome (MetS). MetS refers to a cluster of risk factors (RFs), which are not only associated with the development of cardiovascular (CV) disease (CVD), but also with increased all-cause mortality. In this review, we consider the importance of the circadian rhythm in the regulation of metabolic processes, the significance of circadian misalignment in the pathogenesis of MetS, and the management of MetS in relation to the cellular molecular clock.

Intermittent fasting with ketogenic diet: A combination approach for management of chronic diseases

Intermittent Fasting (IF) is the consumption of food and drinks within a defined time, while the ketogenic diet (KD) switches the metabolism from glucose to fats. Continuation of intermittent fasting leads to the generation of ketones, the exact mechanism for a ketogenic diet. This article discusses the types of IF and KD, the monitoring required, and the mechanisms underlying IF and KD, followed by disorders in which the combination strategy could be applied. The strategies for successfully applying combination therapy are included, along with recommendations for the primary care physicians (PCP) which could serve as a handy guide for patient management. This opinion article could serve as the baseline for future clinical studies since there is an utmost need for developing new wholesome strategies for managing chronic disorders.