Time-restricted feeding regulates lipid metabolism under metabolic challenges

The Interplay of Genetic Predisposition, Circadian Misalignment, and Metabolic Regulation in Obesity

PURPOSE OF REVIEW

This review explores the complex interplay between genetic predispositions to obesity, circadian rhythms, metabolic regulation, and sleep. It highlights how genetic factors underlying obesity exacerbate metabolic dysfunction through circadian misalignment and examines promising interventions to mitigate these effects.

RECENT FINDINGS

Genome-wide association Studies (GWAS) have identified numerous Single Nucleotide Polymorphisms (SNPs) associated with obesity traits, attributing 40-75% heritability to body mass index (BMI). These findings illuminate critical links between genetic obesity, circadian clocks, and metabolic processes. SNPs in clock-related genes influence metabolic pathways, with disruptions in circadian rhythms-driven by poor sleep hygiene or erratic eating patterns-amplifying metabolic dysfunction. Circadian clocks, synchronized with the 24-h light-dark cycle, regulate key metabolic activities, including glucose metabolism, lipid storage, and energy utilization. Genetic mutations or external disruptions, such as irregular sleep or eating habits, can destabilize circadian rhythms, promoting weight gain and metabolic disorders. Circadian misalignment in individuals with genetic predispositions to obesity disrupts the release of key metabolic hormones, such as leptin and insulin, impairing hunger regulation and fat storage. Interventions like time-restricted feeding (TRF) and structured physical activity offer promising strategies to restore circadian harmony, improve metabolic health, and mitigate obesity-related risks.

Effect of time-restricted feeding and caloric restriction in metabolic associated fatty liver disease in male rats

BACKGROUND

The prevalence of metabolic associated fatty liver disease (MAFLD) is high. However, there are few studies on the effects of time-restricted feeding (TRF) and caloric restriction (CR) in MAFLD.

OBJECTIVES

To investigate the efficacy and mechanism of 4 h TRF and 60% CR in MAFLD.

METHODS

Twelve male Sprague-Dawley rats were randomly assigned to the Normal group (normal diet, 10 kcal% fat), while the remaining 38 rats were assigned to the MAFLD group (high-fat diet, 60 kcal% fat). 10 weeks later, the MAFLD group was randomly divided into the 4 h TRF, 60% CR, 4 h TRF + 60% CR, and Model groups; all rats were then given normal diet. After 4 weeks, weight, blood lipid, and other indicators were detected.

RESULTS

After the high-fat diet was discontinued, the liver lipid levels in the rat with MAFLD significantly reduced, while the body weight was not significantly changed. The rats in the Model group were heavier than those in the other four groups (p < 0.01). The triglyceride levels were higher in the TRF + CR group compared with the Model group (p < 0.01). Compared with the Model group, 110 metabolites were decreased in the TRF + CR group, and 83 metabolites were elevated in liver. Kyoto Encyclopedia of Genes and Genomes revealed that the mechanism involved the proliferator-activated receptor alpha signaling pathway, metabolic pathway, and so on. We observed differences in silent information regulator transcript 1 (SIRT1) mRNA levels in all five groups (p = 0.003).

CONCLUSIONS

4 h TRF and 60% CR significantly reduced body weight and liver lipid in rats with MAFLD. 4 h TRF can improve MAFLD, and there is no need to excessively restrict food intake.

Evaluating the effects of time-restricted eating on overweight and obese women with polycystic ovary syndrome: A randomized controlled trial study protocol

BACKGROUND

Time-restricted eating (TRE) manages weight effectively, but choosing how long and what time window remain debatable. Although an 8:00 a.m. to 16:00 p.m. time frame is reported to show positive results in most weight loss trial, its safety and efficacy in overweight and obese women with polycystic ovary syndrome (PCOS) is uncertain. This randomized controlled trial is conducted to evaluate the safety and efficacy of TRE in specific populations.

OBJECTIVE

This study aims to assess the 6-month effects of TRE on weight change, metabolic improvement, reproductive recovery, and health-related quality of life in overweight and obese women with polycystic ovary syndrome (PCOS), compared to those who did not receive TRE.

METHODS

This randomized controlled trial will enroll 96 overweight and obese women with polycystic ovary syndrome (PCOS), who will be randomly assigned to either a TRE group (with an eating window from 8:00 a.m. to 16:00 p.m.) or a control group (without eating time restrictions), with 49 participants in each group. Evaluators and data analysts will remain blinded to group allocation throughout the study. The primary outcomes, including changes in weight and body mass index (BMI), will be assessed weekly. Secondary outcomes, encompassing alterations in sex hormones, metabolic parameters, body composition, sleep quality, quality of life, anxiety, and depression, will be evaluated monthly. Compliance and safety will be continuously monitored throughout the study. Additionally, a 6-month follow-up will be conducted at the end of the trial to assess the long-term effects of TRE. Statistical analysis will include the Anderson-Darling test for normality, T-test/Wilcoxon test based on distribution, mixed-effects models for assessing time/group effects, Cox model for time-to-event analysis, repeated ANOVA for change analysis, and sensitivity analysis. All tests will be conducted using appropriate software, with a significance level set at P<0.05. Missing data will be imputed.

DISCUSSION

The purpose of this study protocol is to further evaluate the effects of TRE in overweight and obese women with PCOS through a randomized controlled trial (RCT). Findings from this study are expected to provide new dietary intervention strategies for overweight and obese PCOS participants.

ETHICS AND DISSEMINATION

This study has received ethics approval from the Medical Ethics Committee of the University of South China (Number: NHHL027). Participants are included after signing informed consent. Results will be submitted for publication in peer-reviewed journals.

TRAIL REGISTRATION

Trail registration number: ChiCTR2400086815.

Synergistic Effects of Time-Restricted Feeding and Resistance Training on Body Composition and Metabolic Health: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis examined the synergistic impact of time-restricted feeding (TRF) combined with resistance training (RT) (TRF + RT) on body composition and metabolic health in adults, contrasting it with habitual eating patterns (CON) and RT (CON + RT).

METHODS

Adhering to PRISMA guidelines, five databases were searched up to 28 April 2024. Randomized controlled trials or crossover trials assessing the effects of TRF + RT for at least 4 weeks in adults were selected. Data were pooled as standardized mean differences (SMDs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs). The risk of bias was evaluated using the revised Cochrane risk-of-bias tool.

RESULTS

Seven studies with 164 participants were included in the final analysis. TRF + RT significantly reduced body mass (WMD -2.90, 95% CI: -5.30 to -0.51), fat mass (WMD -1.52, 95% CI: -2.30 to -0.75), insulin (SMD -0.72, 95% CI: -1.24 to -0.21), total cholesterol (WMD -9.44, 95% CI: -13.62 to -5.27), low-density lipoprotein cholesterol (LDL-C) (WMD -9.94, 95% CI: -13.47 to -6.41), and energy intake (WMD -174.88, 95% CI: -283.79 to -65.97) compared to CON + RT. No significant changes were observed in muscle mass, strength, or other metabolic markers.

CONCLUSIONS

TRF + RT, in contrast to CON + RT, significantly improved body composition, insulin, and cholesterol levels without affecting muscle mass or strength.

Plant-based and Early Time-restricted Eating for Prevention and Treatment of Type 2 Diabetes in Adults: A Narrative Review

Type 2 diabetes (T2D) is a significant public health challenge for which effective lifestyle interventions are needed. A growing body of evidence supports the use of both plant-based eating patterns and early time-restricted eating (eTRE) for the prevention and treatment of T2D, but research has not yet explored the potential of these dietary strategies in combination. In this narrative review, we assessed the evidence by which plant-based diets, in conjunction with eTRE, could support T2D care. The electronic databases MEDLINE and the Web of Science were searched for relevant articles published throughout the last decade. Observational research has shown that healthy plant-based eating patterns and eTRE are associated with reductions in T2D risk. Interventional trials demonstrated that plant-based diets promote improvements in glycated hemoglobin, insulin resistance, glycemic management, and cardiometabolic risk factors. These changes may be mediated, in part, by reductions in oxidative stress, dietary acid load, and hepatocellular and intramyocellular lipids. The eTRE strategies were also shown to improve insulin resistance and glycemic management, and mechanisms of action included enhanced regulation of circadian rhythm and increased metabolic flexibility. Integrating these dietary strategies may produce additive benefits, mediated by reduced visceral adiposity and beneficial shifts in gut microbiota composition. However, potential barriers to concurrent implementation of these interventions may exist, including social challenges, scheduling constraints, and tolerance. Prospective trials are needed to examine their acceptability and clinical effects.

Beneficial effects of time-restricted fasting on cardiovascular disease risk factors: a meta-analysis

BACKGROUND

Cardiovascular disease continues to be a leading cause of mortality worldwide, highlighting the need to explore innovative approaches to improve cardiovascular health outcomes. Time-restricted fasting (TRF) is a dietary intervention that involves limiting the time window for food consumption. It has gained attention for its potential benefits on metabolic health and weight management. This study aims to investigate the impact of TRF on key risk factors, including body weight, glucose metabolism, blood pressure, and lipid profile.

METHODS

We conducted a systematic search in five databases (Scopus, Embase, PubMed, Cochrane, and Web of Science) for relevant studies up to January 2023. After applying inclusion criteria, 12 studies were eligible for analysis. Quality assessment was conducted using the ROB-2.0 tool and ROBINS-I. Risk of bias was mapped using Revman 5.3, and data analysis included Hartung-Knapp adjustment using R 4.2.2.

RESULTS

The group that underwent the TRF intervention exhibited a significant decrease in body weight (SMD: -0.22; 95%CI: -0.41, -0.04; P < 0.05) and fat mass (SMD: -0.19; 95%CI: -0.36, -0.02; P < 0.05), while maintaining lean mass (SMD: -0.09; 95%CI: -0.08, 0.26; P > 0.05).

CONCLUSION

TRF has shown potential as a treatment strategy for reducing total body weight by targeting adipose tissue, with potential improvements in cardiometabolic function.