{"doi":"10.1111/dom.16399","title":"Effectiveness of isocaloric early time‐restricted eating on glucose metabolism in adults: A randomized controlled crossover trial","abstract":null,"journal":"Diabetes, Obesity and Metabolism","year":2025,"id":609908,"datarank":0.10397207708399181,"base_score":0.6931471805599453,"endowment":0.6931471805599453,"self_citation_contribution":0.10397207708399181,"citation_network_contribution":0.0,"self_endowment_contribution":0.10397207708399181,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1567839,"name":"Sisi Deng","orcid":null,"position":1,"is_corresponding":false},{"id":894793,"name":"Wei Xie","orcid":"0000-0001-9563-4927","position":2,"is_corresponding":false},{"id":1567840,"name":"Yuqi Ma","orcid":null,"position":3,"is_corresponding":false},{"id":1567841,"name":"Yeran Jia","orcid":"0009-0005-8513-7173","position":4,"is_corresponding":false},{"id":1567838,"name":"Minfang Weng","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Effectiveness of isocaloric early time‐restricted eating on glucose metabolism in adults: A randomized controlled crossover trial","abstract":"Healthy dietary patterns play a pivotal role in improving metabolic markers. Early time-restricted eating (eTRE) entails abstaining from food intake after noon, typically restricting the eating window to 8 h daily, followed by an extended fasting period. This approach aligns with the circadian rhythm, as prolonging the fasting interval between dinner and subsequent breakfast is generally regarded as a healthier eating pattern. While reducing calorie intake is well established as beneficial for the improvement of metabolic markers, the effects of modifying the eating window on metabolism regulation remain controversial. Many studies suggest that TRE enhances metabolic function by increasing insulin sensitivity and reducing insulin resistance through prolonged fasting1; however, these studies have not demonstrated significant improvements in blood glucose levels. This contradiction highlights the uncertainty surrounding the metabolic effects of TRE. While some studies suggest that aligning meal timing with circadian rhythms enhances glucose control,2, 3 others argue that these benefits are primarily due to caloric restriction (CR) rather than meal timing alone.4 It is crucial to determine the effects of eTRE independent of CR on blood glucose regulation. Our team designed a randomized crossover study to assess the effects of eTRE on blood glucose levels while maintaining constant caloric intake. The details are provided in the Supplemental Material. On 1 September 2022, eligible participants were recruited from adult health check-ups at Guangdong Provincial People's Hospital. Ultimately, eight participants completed the study. The experiment was conducted in two 14-day phases, with participants randomly assigned to one of the two groups using random number tables (Supplemental Figure 1). Each participant wore a real-time continuous glucose monitoring (RT-CGM) device (Shenzhen Silicon Sensor Technology Co., Ltd., CN) to measure tissue fluid glucose levels every 5 min. The devices were used for 14 days (336 h). The first phase began when the device was activated and ended automatically after 336 h. One group of participants had an early dinner (5:00–7:00 PM) for 14 days, whereas the other group had a late dinner (9:00 PM–12:00 AM) for 14 days. Both groups had identical breakfast (7:00–8:00 AM) and lunch (12:00–1:00 PM) schedules. After the first phase, both groups underwent a washout period of more than one month, during which they followed their usual dietary habits. The second phase began when the RT-CGM device was activated and ended automatically after 336 hours. Participants who had an early dinner (5:00–7:00 PM) in the first phase switched to a late dinner (9:00 PM–12:00 AM) in the second phase, whereas those who had a late dinner in the first phase switched to an early dinner in the second phase. The breakfast (7:00–8:00 AM) and lunch (12:00–1:00 PM) schedules remained unchanged. In the second phase, the caloric intake and food type of each meal were required to match those of the corresponding meal on the same day in the first phase. After each phase, the RT-CGM app used glucose data to compute the glucose management indicator (GMI), mean glucose (MG), glucose coefficient of variation (CV), standard deviation (SD), time in range (TIR), time above range (TAR) and time below range (TBR). The details are provided in the supplemental material. Paired t tests were used to compare means between groups. The significance level was set at α = 0.05. There were 8 participants with a mean age of 39.50 ± 9.83 years and a BMI of 21.90 ± 3.68 kg/m2. Their basic characteristics are listed in Table 1. Comparisons between the early and late dinner groups revealed no significant differences in GMI (p = 0.231), MG (p = 0.235), SD (p = 0.406), CV (p = 0.778), TIR (p = 0.257), TAR (p = 0.195) or TBR (p = 0.623) (Table 2). In this study, we found that with equal calorie intake, advancing the dinner time by more than 2 h did not improve tissue fluid glucose levels. Because tissue fluid glucose levels measured by RT-CGM closely reflect blood glucose levels, we conclude that eTRE does not enhance blood glucose metabolism. To contextualize our findings, we compared them to those of previous studies that examined the effects of TRE on glucose metabolism. While some studies have reported that eTRE improves blood glucose levels,2, 3 others indicate that eTRE does not enhance blood glucose metabolism.5-10 A key aspect of this controversy is whether the metabolic benefits of TRE are attributed to CR. If CR is present in a TRE protocol, reductions in blood glucose levels may stem from lower calorie intake rather than shifts in meal timing. Liu et al. conducted a randomized controlled trial to investigate the effects of CR and TRE on weight and metabolism.6 The study found that both groups experienced the same weight loss, with no significant differences in blood glucose levels. This result suggests that CR is the primary driver of weight loss, whereas TRE has no significant effect on weight reduction or blood glucose metabolism. Lowe et al. conducted a randomized clinical trial.4 In this study, the TRE time window was 12:00–8:00 PM. However, there was no significant difference in glucose metabolic indicators compared to the control group (three meals a day with the same calories). This result further demonstrates that the eating rhythm has no impact on glucose metabolism. Lin et al. compared the TRE group, CR group and control group (a regular diet with an eating time window of more than 10 h and unrestricted calorie intake) and found that there was no significant difference in the blood glucose levels of the three groups.11 Queiroz et al. conducted a randomized controlled trial that compared eTRE plus CR, later TRE plus CR and CR alone and found no significant difference in the reduction of blood glucose among the three.9 This finding suggested that TRE does not improve blood glucose metabolism, and CR is the fundamental cause for the improvement of blood glucose metabolism. Some studies have shown that TRE positively influences blood glucose metabolism. A study found that a delayed eating schedule led to an elevated 24-h mean blood glucose level.12 However, the delayed eating schedule matched the 11-h eating window of the control group in this study, with all three meals being postponed by 3.5 h. Both groups maintained the same fasting-to-eating ratio. This result suggests that this study does not establish a causal link between meal timing and elevated 24-h mean blood glucose levels. Similarly, a randomized crossover trial indicated that early dinner improves 24-h blood glucose levels.2 However, the study's findings are less conclusive due to its short duration of only three days. Our study has some limitations. First, it did not quantify energy consumption. Second, exercise levels were not measured, as participants were instructed to maintain their usual exercise habits throughout both phases. Third, owing to the small sample size, the possibility of type II errors increases. The small sample size requires large-scale clinical trials to validate our findings further. Caloric intake may dominate metabolic regulation over meal timing, and further research is required with metabolic disorders to assess potential long-term metabolic adaptations. Simply moving dinner to an earlier time without reducing calorie intake may not effectively enhance glucose regulation. We would like to thank Editage (www.editage.cn) for the English language editing. This study was funded by the Medical Scientific Research Foundation of Guangdong Province, China (C2022009). The authors declare no conflicts of interest. The sponsors had no role in the design, execution, interpretation or writing of this study. The study was conducted in accordance with the guidelines of the Declaration of Helsinki and was approved by the Ethics Committee of Guangdong Provincial People's Hospital (KY-Z-2022-079-01) on 10 May 2022. Informed consent was obtained from all subjects involved in the study. The study protocol and consent procedures were approved by the Ethics Committee of Guangdong Provincial People's Hospital (protocol code KY-Z-2022-079-01). The peer review history for this article is available at https://www.webofscience.com/api/gateway/wos/peer-review/10.1111/dom.16399. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. Data S1. Supporting information. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.","is_dataset_classified":null,"base_score":0.6931471805599453,"endowment":0.6931471805599453,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"40211977","pmcid":"PMC12146466","openalex_id":"https://openalex.org/W4409370748","authors":[],"funders":[{"funder_name":"Medical Scientific Research Foundation of Guangdong Province","grant_id":"C2022009","title":null}],"total_grants":1,"fwci":0.6473,"citation_percentile":0.65542055,"influential_citations":0,"citation_trend":[{"year":2026,"count":1}],"oa_status":"hybrid","license":"cc-by-nc-nd","oa_locations":[{"url":"https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/dom.16399","host_type":"journal"},{"url":"https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/dom.16399","host_type":"publisher"},{"url":"https://dom-pubs.pericles-prod.literatumonline.com/doi/pdf/10.1111/dom.16399","host_type":"publisher"},{"url":"https://doi.org/10.1111/dom.16399","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/40211977","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/12146466","host_type":"repository"},{"url":"https://europepmc.org/articles/PMC12146466","host_type":"Europe_PMC"},{"url":"https://europepmc.org/articles/PMC12146466?pdf=render","host_type":"Europe_PMC"}],"fields_of_study":["Dietary Effects on Health","Diet and metabolism studies","Circadian rhythm and melatonin"],"mesh_terms":[],"keywords":["Medicine","Randomized controlled trial","Crossover study","Internal medicine","Alternative medicine","Circadian rhythm","glucose metabolism","Blood Sugar Regulation","Late Dinner","Time‐Restricted Eating"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Zero hunger"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-07-31T17:20:50.248363Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}