The Effect of Gluten-Free Diet Duration on Body Mass Index of Iranian Patients with Celiac Disease.

: A gluten-free diet (GFD) is the only effective treatment of celiac disease (CD) that is associated with body mass index (BMI) changes. This study aimed to determine how GFD duration affects the BMI of Iranian patients with CD. : In this prospective study, 215 patients with CD, who were on a GFD, were categorized into three groups according to the duration of compliance to GFD: 1. patients with less than 6 months of diet, 2. Patients who had a diet for 6 months to 2 years, and 3. patients with more than 2 years of diet. The BMI changes were assessed before and after adherence to the GFD. : Most patients' weight remains in the same BMI category during different courses of GFD adherence. Patients who were underweight showed significant changes in their BMI following the diet in less than 6 months (=0.033) and more than 2 years (<0.001), and the number of weight gain cases increased over time. : There is a need for careful, updated, and personalized nutrition management of patients with CD in different periods of the diet. Conducting similar studies with larger sample sizes in different regions can lead to providing expert dietary counseling for patients with CD.