Celiac Disease (also known as celiac sprue or gluten sensitive enteropathy) is a chronic digestive and autoimmune disorder that damages the small intestine. The cause is unknown. According to the National Institutes of Health, 2 million people in the United States have celiac disease.

Celiac Disease is unique in that a specific food component, gluten, has been identified as the trigger. Damage to the mucosal surface of the small intestine is caused by an immunologically toxic reaction to the ingestion of gluten and interferes with the absorption of nutrients. Gluten is the common name for the proteins in specific cereal grains. These proteins are found in all forms of wheat (including durum, semolina, spelt, Kamut, einkorn, and faro), and related grains: rye, barley (and its derivatives—malt, malt flavoring, malt vinegar) and triticale (which is a hybrid of rye and wheat) and must be eliminated from one’s diet.

Obesity can make celiac disease worse because it can lead to a delayed diagnosis and more disease progression.

For more info, here’s a reference sheet which you can download and/or print out.