Intermittent Fasting on the Blood Microbiome

Inclusion Criteria: * Age 18-65 years * 18.5 =\< BMI \< 25 kg/m2 * All genders are included. * Have not fasted (go for a day without any food) for any amount of days in the month before the start of the study * Being willing to provide App-derived movement data over the course of the study * Participants are willing to and capable of providing written informed consent. Exclusion Criteria: * Regular use medications such as antibiotics, steroids, beta blockers, and adrenergic-stimulating agents (self-report) * Regular use prebiotic and/or probiotics (self-report) * Intake of antibiotic at least in previous 1 months (self-report) * Daily consumption of \>10 cigarettes, or \>6 cups of coffee (the latter because of the effects on circadian rhythm). (self-report) * Chronic diseases including type 2 diabetes, hypertension, fatty liver disease, cancer, or autoimmune disease (self-report and clinical chemistry) * Internal diseases, including those of the gastrointestinal tract, lung, heart, vasculature, liver, and kidney (self-report and clinical chemistry) * Eating disorder or unconventional eating habits (self-report) * Have a clinically significant abnormality as measured by a blood test * Participation in another study (self-report) * Habit of performing regular fasting (self-report) * Women: pregnancy and breastfeeding (self-report)