Time to Eat - A Personalized Circadian Eating Schedule Leads to Weight Loss Without Calorie Restriction: A Randomized Controlled Trial

ObjectiveMany 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 & MethodsIn a two-group, single center randomized-controlled single-blind pilot study (pre-registration DRKS00021419) with participants aged 18-65 years and BMI [&ge;] 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. ResultsOf 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. ConclusionIn 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. HighlightsO_LIIndividual optimal times for meals are determined via an app-based meal diary. C_LIO_LIGeneration of a structure plan for mealtimes are adjusted to individual circadian clocks. C_LIO_LIFollowing this plan, participants lost an average body weight of 2.6 kg over six weeks. C_LIO_LIWeight loss does not correlate with self-reported changes in food quantity or composition. C_LIO_LIRegular mealtimes contribute to the improvement of general well-being. C_LI