Women could choose to adhere to the low FODMAP diet, over a period of six months. In the first three months, they received extensive guidance by a dietician in training, in addition to supportive materials such as the Monash app, recipes and grocery lists, in the hope of optimal adherence to the diet. After three months, women were asked to continue the diet independently. In addition, women were asked to complete three questionnaires, one every two months. The questionnaires contained the EHP-30, the GIQLI, and self composed questions on their demographics in the first questionnaire, and their strictness of adherence in the second and third questionnaire. The third questionnaire also contained questions on their satisfaction with the dietary guidance and the dietician in training.

Women could choose to adhere to the endometriosis diet, over a period of six months. In the first three months, they received extensive guidance by a dietician in training, in addition to supportive materials such as the Monash app, recipes and grocery lists, in the hope of optimal adherence to the diet. After three months, women were asked to continue the diet independently. In addition, women were asked to complete three questionnaires, one every two months. The questionnaires contained the EHP-30, the GIQLI, and self composed questions on their demographics in the first questionnaire, and their strictness of adherence in the second and third questionnaire. The third questionnaire also contained questions on their satisfaction with the dietary guidance and the dietician in training.

Women were asked to complete three questionnaires, once every two months. These contained the EHP-30 and GIQLI. The first questionnaire contained questions on their demographics, and whether they applied a diet before.

The Low FODMAP diet is an avoidance diet and consist of three phases. In the first phase, all nutrients high in FODMAPs (high-FODMAPS) are eliminated from the daily diet over a period of 2 to 6 weeks to calm down the bowel. The second phase consists of the addition of FODMAP challenges. During this phase the patient continues the Low FODMAP diet, but will reintroduce one high-FODMAP nutrient once every three days to see whether exposure to this high-FODMAP causes IBS symptoms. When this is not the case, the patient can continue eating this high-FODMAP group in their daily diet. In the third and final phase, the diet is fully personalized. This personalization is based on whether the patient tolerated the high-FODMAP nutrient or not during the FODMAP challenges. Only when the high-FODMAP nutrient is not tolerated, it is advised to permanently remove it from the daily diet.

The primary outcome focused on pain scores (in VAS, scale 0-10cm) of the endometriosis-related symptoms dysmenorrhea, deep dyspareunia, chronic pelvic pain, dysuria, dyschezia, tiredness and bloating. Pain scores will be measured on a scale between 0 and 10, where 0 represents no pain at all and 10 the worst pain possible.

Secondary outcome focused on QoL, expressed using the EHP-30 questionnaire. Using the EHP-30, a score between 0 and 100 can be measured for 11 different QoL domains. For every domain, a score of 0 represents best health status through to a score of 100 which represents worst health status.