Butyrate/Hexanoate in Metabolic Health

Inclusion criteria * Overweight/obese men (BMI ≥ 25 kg/m2 and ≤ 34.9 kg/m2); * Aged 40 - 70 years; * Caucasian; * Normal blood pressure (systolic blood pressure 100-140mmHg, diastolic blood pressure 60-90 mmHg); * Weight stable for at least 3 months (± 2 kg). Exclusion criteria * Type 2 diabetes mellitus (defined as fasting plasma glucose ≥ 7.1 mmol/L) * Gastroenterological diseases or abdominal surgery (gallbladder removal and appendix removal are allowed) * Cardiovascular diseases, cancer, liver or kidney malfunction, disease with a life expectancy shorter than 5 years; * Lactose intolerance or other disorders that affect digestion (such as celiac disease) * Abuse of products; alcohol and drugs, excessive nicotine use defined as \>20 cigarettes per day; and excessive alcohol use defined as (\> 15 units/week) * Plans to lose weight or following of a hypocaloric diet in the following three months; * Regular supplementation of pre- or probiotic products (for example Yakult, Activia), use of pre- or probiotics 3 months prior to the start of the study; * Intensive exercise training more than three hours a week; * Use of any medication that influences glucose or fat metabolism and inflammation (i.e. betablockers, corticosteroids, statins or NSAIDs); * Regular use of laxation products in 3 months prior start of study or during study period; * Use of antibiotics in the last three months (antibiotics use can alter substantially the gut microbiota composition). * Follow a vegan diet or vegetarian diet.