This research project aims to study the effect of optimal and individualised nutrition to patients with critical illness during the intensive care unit (ICU) and hospital admission, and until six months after admission. The investigators want to describe and compare the usual care with a dietitian-tailored nutrition care. The hypothesis is that dietitian-tailored nutrition care will result in a higher mean energy intake compared to usual care.

The study will recruit patients with critical illness in one of two groups. Group one will receive standard nutrition care following the current local guidelines. Group two will receive frequent follow-up by a clinical dietitian from inclusion and until six months from admission. The dietitian will be responsible for the nutrition administered to the patient during hospital admission and will have consultations with the patients after discharge. The patients in group two will receive individualized nutrition care and recommendations.

In addition to outcome measures regarding nutrition, the patients can choose if they want to perform physical tests and blood tests as well, but that part of the study is optional. In both groups, outcome measures will be collected at day ten, 30, 90 and 180 days after admission to the ICU. The collection of data will occur even though the patients have been discharged from the hospital, either to their home or another health care facility.

The aim is to study the effect of optimal and individualised nutrition to patients with critical illness during the ICU and hospital admission, and until six months after admission. Firstly, the investigators want to describe the usual care and progression of the patients during the first six months after hospital admission. Secondly, the investigators want to see if frequent follow-up by a clinical dietitian can increase nutritional intake during the same period.

The hypothesis is that dietitian-tailored nutrition care will result in a higher mean energy intake compared to usual care, and that this will further impact other aspects, such as quality of life and physical function.

Inclusion Criteria: Patients in intensive care who gives an informed consent and meet all of the following will be eligible:

1. Admitted to the intensive care unit for >48 hours.

2. At least 18 years of age

3. Have one or more organ system failure (respiratory,cardiovascular or renal) related to their acute illness defined as:

   a. PaO2/FiO2≤300 mm Hg) b. Currently on one or more continuous inotrope/vasopressor infusion which were started at least 4 hours ago at a minimum dose of: i. Norepinephrine≥0.1 mcg/kg/min ii. Epinephrine≥0.1 mcg/kg/min iii. Any dose of vasopressin iv. Milrinone>0.1 mcg/kg/min) c. Renal dysfunction defined as: i. Serum creatinine 2.0-2.9 times baseline or ii. Urine output 0.5 mL/kg/hour for ≥12 hours or iii. Currently receiving renal replacement therapy) d. Currently has an intracranial pressure monitor or ventricular drain in situ

4. Permanent living address in Norway

Exclusion Criteria: Patients will be excluded if:

1. Death is imminent in the next 96 hours or there is a current treatment limitation in place or the patient is unlikely to survive to 180 days due to underlying/chronic illness
2. Dialysis dependent chronic renal failure
3. Suspected or known pregnancy
4. Wheelchair user
5. Cognitive impairment in which intervention is considered not appropriate
6. Eating disorders -

IPD will not be shared due to patient confidentiality. Parts of the data set may be available on reasonable request.