Gut Health Enhancement by Eating Favourable Food

Inclusion Criteria: * Men and Women, aged ≥18 - ≤70 years; * Being able to read and speak Dutch; * Willing to keep a stable dietary pattern throughout the study, apart from the dietary advice in the study; * Having a smartphone compatible with the Lifedata or PocketQ app to fill out the daily questionnaires. Exclusion Criteria: * Having a disease or medical condition which can influence the study results such as diabetes, cancer, diagnosed irritable bowel syndrome, renal disease, liver enzyme abnormality, malignant neoplasm, or a history of inflammatory diseases (such as multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease); * Having a history of intestinal surgery that might interfere with study outcomes (this does not include an appendectomy or cholecystectomy); * Average dietary fiber intake of ≥18 gram (women) or ≥22 gram (men) per day, according to the fiber screen questionnaire (see F1 questionnaires); * More than 3 servings of fermented foods per day as assessed with the fermented food frequency questionnaire (see F1 questionnaires); * Having a Body Mass Index (BMI) of ≥ 30 kg/m2 (self-reported); * Currently following a strict diet and unwilling or unable to change; for example, a gluten free diet or a "crash diet" using meal substitutes; * Specific food allergies that interfere with dietary intervention (for example, gluten, lactose, etc); * Use of prebiotics, probiotics and/or synbiotics (this should be stopped 4 weeks before the start of the s…