The prevalence of obesity and inflammatory bowel diseases (IBD) is increasing. Approximately 15%-40% of patients with IBD are obese. Although the reasons for this trend are unclear, IBD appears to promote accumulation of intra-abdominal fat and mucosal inflammation, leading to increased disease severity, poor quality of life and higher rates of hospitalization and IBD-related surgeries. Limited epidemiological data is available on the economic burden of obesity on patients with IBD in the US.