Hip Fracture Surgery and Oral Nutritional Supplements

Inclusion Criteria: * Age (70+); * Had an acute hip fracture and surgical treatment * Able to walk at least 3 meters without assistance of another person, with or without a walking aid other than a wheeled walker prior to hip fracture MMSE \>=18 (proxy will be informed in addition if MMS-score ≤ 24) * Able to perform the SPPB at baseline * No prior hip fracture * Patient (and/or his/her legal representatives/relatives) understands the study procedure, alternative treatments available and risks involved with the study, and voluntarily agrees to participate by giving his/her (or his/her legal representative's/relatives) written informed consent. Exclusion Criteria: * Baseline visit can not be performed between the second and tenth postoperative day. * Milk protein allergy * Patients with conservative treatment for hip fracture * Serum calcium adjusted for albumin of \> 2.6 mmol/L * Pathologic fracture in the last year (except for fractures due to osteoporosis) * Chemo therapy / Radiation /antihormonal therapy due to cancer in the last year * Treatment which has an effect on calcium metabolism (e.g. PTH, calcitonin, chronic cortisone intake \> 5mg/day in the last 12 months (except for inhalation and sporadic infiltration)) * Oral vitamin D intake of more than 1000 IU per day during the last 3 months before the study * Unwilling to stop multi-vitamin, calcium supplementation, and vitamin D supplementation during the trial (maximal calcium supplement intake 250mg/d; no additional vitamin D supplementation). We will inform the treating physician that we initiated vitamin D supplementation as standard of care. * Severe visual or hearing impairment * Unwilling or unable to take study medication * Diseases with a risk of recurrent falling (e.g. Parkinson's disease/syndrome, Hemiplegia after stroke, symptomatic stenosis of the spinal canal, polyneuropathy, epilepsy, recurring vertigo, recurring syncope) BMI ≥ 40 * Estimated creatinine clearance \< 15 ml/min (estimated Creatinine Clearance cockcroft and Gault) * Malabsorption syndrome (celiac diseases, inflammatory bowel disease, hepatic and/or pancreas dysfunction) * Diseases that may enhance serum calcium: sarcoidosis, lymphoma, primary hyperparathyroidism * Kidney stone in the last 10 years * Patient heavily consumes alcohol containing products defined as greater than (\>) 3 drinks (beer, wine, or distilled spirits) of alcoholic beverages per day. * Patients who are planning a stay in a "sunny" location (e.g. winter sun resort) for more than one month during the trial * Medication which has an effect on serum 25-hydroxyvitamin D level (e.g. certain anticonvulsants (e.g. Phenobarbital, Carbamazepin, Phenytoin) M. Paget (Ostitis deformans) * Inflammatory arthritis (e.g. rheumatoid arthritis, reiter syndrome, psoriasis arthritis) * Uncontrolled metabolic conditions, or psychiatric conditions that might make tolerance or evaluation of the feeding formula difficult * Severe acute and/or chronic disease that makes the performance of the study assessments impossible (e.g. severe infection/sepsis, myocardial infarction, heart failure, respiratory failure or renal failure); * Patient is taking peripherally acting anti-adiposity drugs (e.g. Xenical®, formoline L112®, (Acomplia®)) * Patients taking protein supplements (\>15g per serving more than once a week) or are unwilling to stop any protein supplements during the trial Participation in a study in the last 6 month, except for studies without drug-application, or any influence of the study-medication can be excluded * Patient is unlikely to adhere to the study procedures, to keep appointments, or is planning to relocate during the study.