 In Part 2 a 2-armed randomized controlled intervention study is performed . One group starts with a dietary intervention whereas the second group controls starts with a non-interventional period of 6 months. After this period the dietary intervention is also performed in the second group . The dietary intervention implies optimizing the diet based on individually calculated energy and protein requirements, while for remaining nutrients advise in line with recommended daily amounts RDA will be provided. Extended Nutritional Assessment measurements will be repeated every 3 months. Indirect Calorimetry will be performed at the start of the study. 