Final answer:
Individuals with celiac disease must follow a strict gluten-free diet, as consuming gluten damages their small intestine's microvilli, leading to malnutrition and other health problems.
Step-by-step explanation:
People with celiac disease must eliminate all gluten-containing foods from their diet. Gluten is a protein found in grains like wheat, barley, and rye. Consumption of gluten by someone with celiac disease causes an immune response that results in damage to the microvilli of the small intestine. This damage impairs nutrient absorption leading to symptoms such as malnutrition, cramping, and diarrhea. Therefore, foods like bread, pasta, and other baked goods that traditionally contain wheat should be avoided. Strict adherence to a gluten-free diet is the primary treatment for managing celiac disease and preventing its serious complications.