Introduction: Clinical research to develop treatment for inflammatory bowel disease (IBD) is focusing on a nutritional regimen restricting certain carbohydrates while incorporating the use of an optimal diet that includes pre- and probiotic foods. Current assessments are not able to measure elements of this nutritional regimen, thus we developed a food frequency questionnaire (FFQ). This FFQ will be utilized in a prospective study of IBD patients following an anti-inflammatory diet (IBD-AID) developed by us and used clinically at UMASS. We will track the bacterial communities inhabiting the microbiome of patients to determine diet-dependent changes, and their relation with patient wellbeing. Objectives: 1) Develop an FFQ capable of identifying dietary components important to IBD: prebiotics, probiotics, beneficial nutrient intake, and avoidance of certain foods. 2) Determine diet-dependent changes of the gut microbiome. Hypothesis: This study will show the microbiome of patients adopting the IBD-AID converge to one or more healthy 'enterotype' signatures, as compared to a non-IBD-AID control group. Experimental design: Patients record daily FFQ. Foods and food groups (270) are categorized and grouped according to criteria of interest. Each food has a referent by which the patient can compare their own consumption. A scoring system satisfying dietary guidelines and components of the IBD-AID will be utilized. Twice per week patients collect stool samples for microbiome analysis. Microbiome composition and ecological metrics are compared to identify components influenced by the IBD-AID, and to separate bacterial 'enterotype' signatures of patients before, during and after diet intervention. We are currently recruiting patients.