Rationale: Nutrition and lifestyle interventions are currently not implemented in usual clinical care of PAH-patients. Mainly because there is little known on the relation between pathology, nutrition and lifestyle. Patients who suffer from Pulmonary Arterial Hypertension feel insecure about their nutrition and lifestyle. The investigators hypothesize that an intervention on nutrition and lifestyle can improve the patients' quality of life.

Objective: To explore the effect of a nutrition and lifestyle intervention on quality of life for patients suffering from PAH.

Study design: Investigator initiated intervention study with control group. Study population: investigators aim to include 70 patients (18 - 80 years) with idiopathic, hereditable or drug related PAH, who have been stable for at least three months and are self-sufficient and/or have a family who's willing to participate in the lifestyle changes.

Intervention (if applicable): Nutritional status, - education, - intervention and - compliance.

Main study parameters/endpoints: This is an intervention study in which the investigators will asses the effect of a nutrition and lifestyle intervention on quality of life measured by SF-36 overall outcome with a significant difference of 6.35.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The burden for the patient exists of 12 extra visits to the hospital and contact moments, over a period of 11 months, as well compliance to the diet and lifestyle. There is minimal risk in participation.

Baseline nutritional assessment

Nutritional education:

8 online lessons containing information about nutrition, lifestyle and general health with complementary tips regarding PH. All participants recieve workbook with assignments.

Nutritional intervention:

Group A: MedDASH diet (55% carbohydrates, 25% amino acids, 20% fatty acids) Group B: MedDASHfat diet (10% carbohydrates, 25% amino acids, 65% fatty acids) Control group: no diet.

Follow-up:

Patients in intervention arm followed for a period of 6 months to assess compliance.

Inclusion Criteria:

• Diagnosis of idiopathic PAH, hereditable PAH or drug related PAH
• Age between 18 and 80
• NYHA II or III and stable for at least 3 months, determined by a stable 6minute walk test with a difference of <10%.
• Self-sufficient and/or compliance from partner and/or family
• Creatinine > 30 ml/min
• Able to understand and willing to sign the Informed Consent Form

Exclusion Criteria:

• - Pregnant subjects
• Fat percentage < 10% > 50 %
• One or more of the following comorbidities: diabetes mellitus type one or two, clinically relevant thyroid disease
• Known history of noncompliance considering therapies

Data of the study will be kept by the principal investigators and will be available for regulatory authorities. Subjects' personal data will be stored confidentially according to institutional routine. In principle, results will be published in peer-reviewed international journals.

Randomisation control and E-learning Randomisation Diet A and B