This is a prospective, interventional pilot study to assess the feasibility and optimal timing of a multimodal intervention program in Ulcerative Colitis (UC) patients with active disease as well as in patients in remission. Secondly, to demonstrate the effects of a multimodal intervention program on individual patients level and therapy outcomes.

Rationale: Despite considerable advances in the knowledge of UC, and a variation of treatment options, UC still impacts patients' ability to lead a normal life. Clearly, there is an unmet need to improve treatment outcomes. Prehabilitation programs in surgery have shown that the amount of complications is closely related to preoperative physical fitness, nutritional status and psychological well-being. IBD patients often search for self-management strategies to manage their symptoms, however, research focussing on a multimodal intervention approach in parallel to starting new IBD treatment is lacking. Given the potential benefits of intervention programs, limitations of current treatments in terms of improving quality of life and patients' desire for self-management options, we believe that exploring the results of a multimodal intervention program in patients with UC is of high relevance.

Objective/study design: This is a prospective, interventional pilot study to assess the feasibility and optimal timing of a multimodal intervention program in UC patients. Secondly, to demonstrate the effects of a multimodal intervention program on individual patients level and therapy outcomes.

Study population: Patients ≥ 18 years old, with UC. Intervention: Multimodal intervention program including an exercise program, nutritional intervention and psychological evaluation.

Main study parameters/endpoints: This study assesses the feasibility of a multimodal intervention program. Secondary, assesses the effect on:

• Individual patients' level, i.e. physical fitness, nutritional status, mental health, quality of life and work productivity and activity impairment.
• Therapy outcomes, e.g. adherence, number and severity of (S)AEs, corticosteroid use, biochemical and clinical response/remission rates and patient reported outcomes.

Inclusion Criteria:

• Age ≥ 18 years old;
• Diagnosis of UC confirmed by clinical, endoscopic, and/or histological evidence prior to screening as per standard criteria;
• Ability of subject to participate fully in all aspects of this project;
• Written informed consent must be obtained and documented.

Exclusion Criteria:

• Suspicion of differential diagnosis of CD, indeterminate colitis, ischemic colitis, radiation colitis, diverticular disease associated with colitis, or microscopic colitis;
• Serious underlying disease other than UC that in the opinion of the investigator may interfere with the subject's ability to participate fully in the study or would compromise subject safety (such as history of malignancies, major neurological disorders, certain orthopedic impairments or any unstable, uncontrolled or severe systemic medical disorder);
• History of alcohol or drug abuse that in the opinion of the investigator may interfere with the subject's ability to comply with the study procedures;
• History of psychiatric disorders that in the opinion of the investigator may interfere with the subject's ability to comply with the study procedures;
• If female, the subject is pregnant or lactating (< 1 year) or intending to become pregnant;
• Immobilized patients who are not able to complete exercise intervention;
• Illiteracy (disability to read and understand Dutch).