Pain in Endometriosis And the Relation to Lifestyle

Inclusion Criteria:

• Confirmed diagnosis of endometriosis via ultrasound, MRI or surgery*

• NRS pain score > 4*

• Age from 17 years

• Premenopausal status

• Body Mass Index (BMI) 18-30 kg/m2

• Ability to understand the explanation about the diet intervention (DI) and CBT*

• Willing to follow the DI*

• Willing to continue their use of food supplements

• Willing to undergo CBT*

• Willing to collect menstrual effluent, and therefore willing to have two stop weeksfrom hormonal contraception (if applicable) during the study period.

Exclusion Criteria:

• Recurrent miscarriages (> 2)

• Eating disorder

• Diagnosed with Crohn's disease, Ulcerative Colitis, short bowel syndrome or anotherchronic inflammatory disease

• Self-reported celiac disease

• Vegan diet

• Smoking

• Use of immunosuppressive or psychotropic medication

• Score on FFQ > 120

• Diagnosed with severe mental disorder currently requiring treatment by psychiatrist

• NRS average score below 4 during the last month

• Participation in another intervention study

• Unable to speak Dutch or to understand the intervention

• Need for surgery during the participation in the study

• Serious pain (NRS > 4) from other origin than endometriosis

• Pregnant

• Scalp hair shorter than 4 cm

• Only applicable to patients with endometriosis