The Effect of Prebiotics on Gastrointestinal Functioning and Metabolism

Inclusion Criteria: * Overweight to obese men and women (BMI ≥ 25 kg/m2 \<35 kg/m2) * Aged 20-50 years * Caucasian * Normal fasting glucose (\<6.1 mmol/L.) * Normal blood pressure (systolic blood pressure 100-140 mmHg, diastolic blood pressure 60-90 mmHg) * Weight stable in last 3 months (±2 kg) * A low defecation frequency, \<4 times/week and no constipation or underlying pathology, as determined by gastro-intestinal questionnaires). * A slow whole gut transit (\>35h) Exclusion Criteria: * Woman lactating, pregnant (where pregnancy is defined as the state of a female after conception and until the termination of gestation, confirmed by a positive hCG laboratory test) or (post)-menopausal * Regular smokers * People with intensive fitness training, eg. athletes (≥3 per week ≥ 1 hour training) * Diabetes Mellitus (defined as FPG ≥ 7.0 mmol/l and or 2h PG ≥ 11.1 mmol/l) * Gastro-intestinal diseases or abdominal surgery, cardiovascular diseases, cancer, liver or kidney malfunctioning (determined based on ALAT and creatinine levels, respectively) disease with a life expectation shorter than 5 years * Following a hypocaloric diet * Gluten intolerance * Regular use of laxation products, or use of antibiotics, probiotics or prebiotics 3 months prior to the start of the study * More than 2 symptoms occurring over a period of 12 weeks in the preceding 12 months such as 1. Straining in \>1/4 defecations; 2. Lumpy or hard stools in \>1/4 defecations; 3. Sensation of incomplete evacuation in \>1/4 defecations; 4. Sensation of anorectal obstruction/blockade in \>1/4 defecations 5. Manual maneuvers to facilitate \>1/4 defecations (e.g., digital evacuation, support of the pelvic floor); and/or 6. \<3 defecations/week * Current use of medication interfering with study intervention or interfering with study endpoints/hypotheses * Not to be able to understand the study information * Blood donation 2 months prior to the study and during the study * Participation in other studies