Since celiac disease is an autoimmune illness, it is the same body that aims to protect you from the disease that contributes to the damage that this disease makes. When someone with celiac disease eats any kind of gluten like barley, wheat, or rye, you can expect that person to have such symptoms like diarrhea, malabsorption, stunted growth for those who are still children, and others. It is because the disease is causing damage to the villi, the finger-like projections along the lining of the small intestine. When completely damaged, the small intestine will not be able to absorb nutrients which are needed to keep the body fully functioning. Since the different systems in our body solely rely on the food that you eat to make the other systems function, it will be detrimental for you, in the long run, to eat gluten consistently.