Although it is reported that refeeding too cautiously can place patients at even further risk of malnutrition, postpone recovery and lead to unnecessary loss of physical function but NICE has stated that guidelines cannot be changed unless more high-quality RCTs are performed. This study will provide new knowledge regarding how to refeed severely malnourished elderly patients. By providing them with 40% more calories and protein the first 7 days of hospitalization one can expect faster improvements in regards to physical function, independency, reduced readmission-and mortality rates. In addition this study provides new knowledge regarding the necessity to monitor phosphate levels in patients not identified as at risk of developing RFS.