The Effect of a 12-week Self-composed Vegan Diet With or Without Concurrent Resistance Exercise on Thigh Muscle Volume in Older Adults (Vold)

Inclusion Criteria: Aged ≥65 years old; Community-dwelling; BMI 25-32 kg/m2; Habitual diet contains animal-based food products (i.e. dairy, meat and/or fish) at least 5 days per week; Exclusion Criteria: Following a self-reported entirely vegetarian or vegan diet during the six months prior to the study; Following a prescribed high (≥1.2 g/kg/d) or low protein diet (<0.8 g/kg/d), and/or or taking protein supplements on medical advice, during the month prior to the study; Participating in a structured progressive resistance exercise training program the during three months prior to the study; ≥4 kg of body weight loss during three months before the start of the study; Being diagnosed with one of the following: diabetes mellitus; renal disease; neurological or neuromuscular disorders; serious cardiovascular diseases; cancer (with the exception of the following types of skin cancer: basal cell carcinoma, squamous cell carcinoma); (very) severe chronic obstructive lung disease (COPD; GOLD stage III or IV); bowel disease. Chronic use of medication that affects muscle function as assessed by the research physician; The use of anticoagulants incompatible for muscle biopsies as assessed by the research physician: acenocoumarol (sintrom); phenprocoumon (marcoumar); dabigatran (pradaxa); apixaban (eliquis); rivaroxaban (xarelto); clopidogrel (plavix); edoxaban (lixiana); combination of acetylsalicylic acid or carbasalate calcium (ascal) with dipyridamole; Having a contra-indication to MRI scanning (including, but not limited to): Pacemakers and defibrillators Infraorbital or intraocular metallic fragments Ferromagnetic implants Claustrophobia Not willing to stop nutritional supplements, with the exception of supplements on medical advice, and vitamin D; Not willing or afraid to give blood, undergo a muscle biopsy or have an MRI scan during the study; Unwilling to eat a self-composed vegan diet or an omnivorous diet with daily consumption of animal-based food sources for 3 months; Unwilling to participate in RE twice a week for 3 months; Currently a research participant in another trial or participated in a clinical trial during one month before the start of the measurement period; Not being able to understand Dutch; Not having a general physician; Working, or having a direct family member that work at the Division of Human Nutrition at Wageningen University during the study. Unwilling to be informed about incidental findings of pathology and approving of reporting this to their general physician.