Promoting Immune Health by Intermittent Fasting: a Pilot Study

Inclusion Criteria metsyn: * BMI 30 to 43 kg/m2 * HOMA-IR index larger/same as 2.5 * And At least 3 out of 5 NCEP (National Cholesterol Education Program) metabolic syndrome criteria: * Fasting plasma glucose ≥ 6.1 mmol/l, * Triglycerides≥1.7mmol/l, * Waist-circumference\>102cm, * HDL-cholesterol\<1.04mmol/l, * Bloodpressure≥130/85mmHg). Inclusion healthy volunteers * Body mass index (BMI) 18 to 25 kg/m2, * Waist circumference between 79 cm and 94 cm and * HOMA-IR index: ≤ 2.0 (measured as fasting insulin (pmol/L) x fasting glucose (mmol/L)) / 135) Exclusion criteria; (all) * Excessive weight loss of \>10% in the last months; * Use of any medication, including proton pomp inhibitors and antibiotics in the past three months; * Cholecystectomy; * Untreated GI disease/abnormal bowel habits; * Plasma aspartate aminotransferase and alanine aminotransferase are 2.5 times or more the upper limit of the normal range; * A history of cardiovascular event (MI or pacemaker implantation); * A history of heavy alcohol use (\>12 to 15 g of alcohol per day, or \>12 oz of beer, 5 oz of wine, or 1.5 oz of distilled spirits); * A dependency on alcohol or unable to pause the consumption of alcohol during the study period. * An (expected) prolonged compromised immunity (due to recent cytotoxic chemotherapy or HIV infection with a CD4 count \< 240); * Unmotivated or not able to adhere to a specific diet; * History of eating disorder; * Night workers or people with deviant day/night rhythm; * Pregnant, trying to get pregnant or breast feeding at inclusion; * Irregular menstrual cycle; * Hormonal replacement therapy (other than oral contraceptives).