10-h time-restricted eating: are there broad health benefits?

Time-restricted eating (TRE) is increasingly recognised as a straightforward and effective dietary intervention, particularly beneficial for individuals at high risk of or who currently have conditions such as overweight, obesity, or type 2 diabetes.1Ezzati A McLaren C Bohlman C Tamargo JA Lin Y Anton SD Does time-restricted eating add benefits to calorie restriction? A systematic review.Obesity (Silver Spring). 2024; (published online Feb 21.)https://doi.org/10.1002/oby.23984Crossref PubMed Scopus (0) Google Scholar The principle behind TRE involves confining the daily eating-time range to a specific number of hours, typically ranging from 8 h to 12 h, and fasting for the remaining hours of the day. This method is believed to synchronise eating patterns with the natural circadian rhythms of the body, thereby optimising metabolic processes. The potential benefits of TRE extend beyond mere weight loss. Research has indicated that this dietary approach might mitigate markers associated with cardiovascular diseases. By regulating the timing of food intake, TRE can influence various protective factors that contribute to cardiac metabolic health. Among these factors are improved blood pressure and blood sugar, which are crucial in managing and preventing the progression of cardiovascular conditions. Furthermore, weight loss achieved through TRE can further reduce the strain on the heart and improve overall cardiovascular health.2Lin S Cienfuegos S Ezpeleta M et al.Time-restricted eating without calorie counting for weight loss in a racially diverse population: a randomized controlled trial.Ann Intern Med. 2023; 176: 885-895Crossref PubMed Scopus (14) Google Scholar, 3Ozcan M Abdellatif M Javaheri A Sedej S Risks and benefits of intermittent fasting for the aging cardiovascular system.Can J Cardiol. 2024; (published online Feb 12.)https://doi.org/10.1016/j.cjca.2024.02.004Summary Full Text Full Text PDF PubMed Google Scholar, 4Cheung K Chan V Chan S et al.Effect of intermittent fasting on cardiometabolic health in the Chinese population: a meta-analysis of randomized controlled trials.Nutrients. 2024; 16: 357Crossref PubMed Scopus (0) Google Scholar Jonas Salling Quist and colleagues5Quist JS Pedersen HE Jensen MM et al.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.Lancet Healthy Longev. 2024; (published online April 5.)https://doi.org/10.1016/S2666-7568(24)00028-XGoogle Scholar conducted a single-centre, parallel, superiority, open-label randomised controlled trial at the Steno Diabetes Center Copenhagen in Denmark to examine the effects of 3 months of 10-h TRE on weight and cardiac metabolic risk factors in a population at high risk for type 2 diabetes, and to explore whether potential changes in weight and cardiac metabolic risk markers could be sustained for an additional 3 months. Unlike most trials of TRE to date, which featured smaller sample sizes, this trial is important due to its larger cohort of 100 participants, who were divided into two groups of 50. Notably, Quist and colleagues used continuous glucose monitoring, had a low dropout rate, and reported high adherence to the TRE intervention, giving their findings scientific reliability and high external validity. Contrary to their hypothesis and previous perspectives, Quist and colleagues found that 3 months of 10-h TRE did not lead to weight loss or improved cardiac metabolic health in the population at high risk for type 2 diabetes. Although TRE did result in improvements within the group in BMI, fat percentage, waist circumference, alanine aminotransferase, and glycaemic control, there were no statistically significant differences in outcomes for the TRE group compared with the control group (who underwent 3 months of habitual living). Similar scepticism about the effectiveness of TRE has been noted in other studies, with one particular 10-h TRE study showing no significant weight loss.6Manoogian ENC Zadourian A Lo HC et al.Feasibility of time-restricted eating and impacts on cardiometabolic health in 24-h shift workers: the Healthy Heroes randomized control trial.Cell Metab. 2022; 34: 1442-1456Summary Full Text Full Text PDF PubMed Scopus (47) Google Scholar However, the fasting-time range when eating is restricted to 10 h is shorter than the range in studies reporting positive outcomes, which typically involved longer fasting-time ranges as eating was restricted to 6 h or 8 h.7Rovira-Llopis S Luna-Marco C Perea-Galera L Bañuls C Morillas C Victor VM Circadian alignment of food intake and glycaemic control by time-restricted eating: a systematic review and meta-analysis.Rev Endocr Metab Disord. 2023; (published online Nov 22.)https://doi.org/10.1007/s11154-023-09853-xPubMed Google Scholar On the basis of their findings, Quist and colleagues do not recommend 10-h TRE as a short-term (ie, 3 months) strategy for weight loss and metabolic health improvement. However, an unresolved question remains: given the typical time to benefit from dietary treatments and that previous energy-restriction interventions often took a long time to become a lifestyle habit, could it be that 10-h TRE, as a convenient and feasible dietary strategy, requires a longer duration than 3 months (eg, 6 months or 12 months) to exert protective effects on weight and heart health? For example, an 8-h TRE intervention during 6 months was effective in reducing bodyweight and HbA1c.8Pavlou V Cienfuegos S Lin S et al.Effect of time-restricted eating on weight loss in adults with type 2 diabetes: a randomized clinical trial.JAMA Netw Open. 2023; 6e2339337Crossref PubMed Scopus (3) Google Scholar Without large-scale trials of increased durations to continue observing changes in weight and cardiac-health indicators, concluding that TRE is ineffective in populations at high risk for overweight, obesity, and type 2 diabetes could be premature. As Quist and colleagues mention, long-term studies of individuals with obesity or metabolic dysfunction are scarce. Nevertheless, the trial conducted by Quist and colleagues5Quist JS Pedersen HE Jensen MM et al.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.Lancet Healthy Longev. 2024; (published online April 5.)https://doi.org/10.1016/S2666-7568(24)00028-XGoogle Scholar is meaningful. It provides an objective evaluation of the short-term effects of 10-h TRE, challenging the so-called mythical expectations of the efficacy of various TRE interventions. Perhaps future strategies should consider combining TRE with calorie-restriction diets for improved effectiveness.9He M Li B Li M Gao S Does early time-restricted eating reduce body weight and preserve fat-free mass in adults? A systematic review and meta-analysis of randomized controlled trials.Diabetes Metab Syndr. 2024; 18102952Crossref Scopus (0) Google Scholar We hope this trial will motivate further exploration into convenient and effective weight loss interventions. We declare no competing interests. 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 trial3 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.