Effects of Daytime Dry Fasting on Hydration, Glucose Metabolism and Circadian Phase: A Prospective Exploratory Cohort Study in Bahá'í Volunteers

Background: Religiously motivated Bahá'í fasting (BF) is a form of intermittent dry celebrated by abstaining from food and drinks during daylight hours every year in March for 19 consecutive days. Aim: To test the safety effects BF on hydration, metabolism, circadian clock. Methods: Thirty-four healthy volunteers (15 women) participated this prospective, exploratory cohort study. Laboratory examinations were carried out four study visits: before (V0), third week (V1) as well 3 weeks (V3) months (V4) after fasting. Data collection included blood urine samples, anthropometric measurements bioelectrical impedance analysis. At V0 V1, 24- 12-hour serum osmolality measured. V0–V2, alterations clock phase monitored 16 participants. Our was augmented an additional survey with 144 filling questionnaires subgroups attending metabolic ( n = 11) qualitative interviews 13), results which will be published separately. Results: Exploratory data analysis revealed that 34, p < 0.001) 24-hour (n 0.003) decreased daytime but remained largely within physiological range returned to pre-fasting levels night hours. BMI (body mass index), total body fat mass, resting rate 0.001), while cell water appeared unchanged. The estimated transcript biomarkers monocytes advanced 1.1 h 16, 0.005) values Most observed changes not detectable anymore Conclusions: Results indicate (Bahá'í fasting) safe, has no negative can improve metabolism cause transient shifts rhythms. Trial Registration: https://www.clinicaltrials.gov/ , identifier: NCT03443739.