Coeliac disease is an autoimmune disorder in people when the indigestion of Gluten leads to problems in the body. If someone with coeliac disease eats something with gluten (for example, wheat, rye, barley), cells inside the body attack the lining of the intestine. This means that they cannot digest (eat) food properly, making them unable to have enough energy, vitamins, or minerals. Children may be unable to grow taller or gain weight properly. People with coeliac disease often lose weight. They are also frequently tired.