In this study, we aim to identify a well consumable butyrate/hexanoate-enriched oil that increases circulating SCFA concentrations and improves postprandial substrate metabolism, which could be further used for a long-term study.

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.