Dietary Fiber Before Colorectal Cancer Surgery

The aim of this randomized controlled trial is to investigate the feasibility of increasing preoperative dietary fiber intake in individuals with colorectal cancer who will undergo surgery. This will be done using 1) digital personalized dietary advice or 2) a dried vegetable product compared to 3) habitual diet (control).

Inclusion Criteria: * Age ≥18 years; * Being diagnosed with CRC and planned to undergo elective CRC resection; Exclusion Criteria: * Previously have had a large abdominal resection, excluding appendectomy and cholecystectomy; * Diagnosed with Crohn's disease, Ulcerative Colitis, Celiac Disease; * Currently having a stoma; * Known allergic reactions to plants from the Asteraceae (Compositae) family (e.g., lettuce, daisies, sunflowers, artichokes, sage, tarragon, chamomile, chicory etc.); * Currently following a strict diet and unwilling or unable to change (e.g., gluten free or ketogenic diet); * Currently using fiber supplements, prebiotics and/or probiotics and unwilling to stop using these for the duration of the intervention; * Having a habitual dietary fiber intake \>30 g/day for women and \>40 g/day for men, measured with a food frequency questionnaire; * Dementia or other cognitive disabilities that makes it impossible to fill out questionnaires correctly; * Illiteracy (inability to read and understand Dutch).