Elena Shekhova, PhD (@lumipie.com)

Time to Eat - A Personalized Circadian Eating Schedule Leads to Weight Loss Without Imposing Calorie Restriction: A Randomized Controlled Pilot Study Objective Many weight loss strategies are based on the restriction of calories or certain foods. In this pilot study, we preliminary tested a weight loss intervention based solely on increasing the regularity of meals. The assumption is based on the evidence that eating at fixed times allows the circadian system to optimally prepare the food metabolism for these times. Participants & Methods In a two-group, single center randomized-controlled single-blind pilot study (pre-registration DRKS00021419) with participants aged 18-65 years and BMI ≥ 22 kg/m2, we used a smartphone application to identify the times at which each participant eats particularly frequently and asked participants of the experimental group to restrict their meals to only these times for six weeks. Control participants received sham treatment. Primary outcome was body weight/BMI and secondary outcome the well-being of participants. Results Of 148 participants taking part in the pilot study, 121 were randomized, of whom 100 (control: 33, experimental: 67) completed the study. Our results show that the more regular the meals of participants of the experimental group became, the more weight/BMI they lost, averaging 2.62 kg (0.87 kg/m2); p < 0.0001 (BMI: p < 0.0001) compared to an insignificant weight loss of 0.56 kg (0.20 kg/m2) in the control group; p = 0.0918 (BMI: p = 0.0658). Strikingly, weight loss was not related to self-reported changes in calories, food composition, and other food-related factors. Additionally, physical and mental well-being improved significantly. Conclusion In summary, increasing the regularity of meals may cause participants to lose excess body weight and improve overall well-being. These promising results justify a larger-scale study, albeit with a more rigorous study design. Highlights ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial DRKS00021419 ### Funding Statement This work was supported by an Emmy Noether fellowship: LA4126/1-1 of the Deutsche Forschungsgemeinschaft to DL. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics Committee of Ludwig Maximilian University gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors. The codes used to calculate MTVS, individual optimal number of meals, and personalized optimal eating times will be available at <https://github.com/dolandgraf/Time-To-Eat.git> as of the date of publication of this paper. * CG : Control group EG : Experimental group IDS-SR : Self-Assessment Inventory of Depressive Symptoms MCTQ : Munich Chronotype Questionnaire MTVS : Meal time variability score PSQI : Pittsburgh Sleep Quality Index SF-36 : 36-Item Short Form Health Survey SWE : Scale of General Expectations of Self-Efficacy TRE/TRF : time-restricted eating/feeding https://doi.org/10.1101/2024.01.30.24301983