A diet high in animal meat and fat has been linked to an increased risk for ulcerative colitis (UC) and high meat intake increases the likelihood of UC flares. Despite these correlations, there has never been a controlled, prospective study to investigate the contribution of dietary fat to inflammation and the quality of life in patients with UC. In this pilot, cross-over design study, patients with UC were randomized and given two, 4 week, isocaloric dietary interventions with a 2 week wash out between diets: a low fat diet (LFD), containing 10% total calories from fat, and a standard American diet (SAD), containing 35-40% total calories from fat.