Inclusion Criteria:  Male or female persons without probable, confirmed or severe sarcopenia according to the European Working Group on Sarcopenia in Older People (EWGSOP2): no reduced muscle strength measured by chair stand test or hand grips strength 65 years or older Community-dwelling elderly or assisted living Dutch speaking  Exclusion Criteria:  Impairments/diseases that affect performance of daily activities Persons who are systematically physically active (e.g. routine or organized sports activities) or who followed a physical activity training program (e.g., rehabilitation program) in the last 6 months (systematically = twice or more/week) Diagnosis of diabetes mellitus, measured by fasting glucose ≥126 mg/dL or HbA1C ≥ 6.5% at screening or in recent (maximum 3 months old) lab report Use of antibiotics in the last 3 months Gastrointestinal cancer (active or treated in the last 5 years) No freezer at home available  After the screening visit, included persons will be invited for a test visit.