This clinical study is designed to evaluate the effect of Mediterranean diet as an add-on therapy for induction of remission in adult patients with active Crohn's disease and to evaluate its effects on clinical, inflammatory and microbial parameters.

The Mediterranean diet has been associated with anti-inflammatory properties and with decreased risk for several chronic diseases. However, the effect of Mediterranean diet has not been evaluated in patients with inflammatory bowel diseases.

The purpose of this study is to determine whether Mediterranean diet is superior to a low residue diet as an add-on therapy for induction of remission in adult patients with active Crohn's disease and to evaluate its effects on clinical, inflammatory and microbial parameters.

Seventy eligible patients will be randomly assigned to one of two dietary interventions: Mediterranean diet or low residue diet, as an add-on therapy for induction of remission of active Crohn's disease. The effect of the dietary regimens on clinical, inflammatory and microbial parameters will be assessed at 8 and 52 weeks.

Inclusion Criteria:

• Males and females
• Age: 18-75
• Diagnosis of Crohn's Disease
• Montreal classification- B1
• CDAI: 150-450 + CRP>0.5 or fecal calprotectin >200
• Induction therapy with corticosteroids, 5-ASA, AZA, 6-MP, MTX or biologic therapy
• Capacity to give informed consent

Exclusion Criteria:

• Ileostomy or colostomy
• Exclusive enteral nutrition/ partial enteral nutrition
• History of or current severe systemic diseases
• History of admission due to bowel obstruction
• Positive Clostridium difficile toxin
• Positive Salmonella, Shigella, Campylobacter, stool culture
• Pregnancy or lactation
• Use of antibiotics or steroids one month prior to inclusion