Human: I've heard that a lot of people are switching to a gluten-free diet. What does that mean? Assistant: 
A gluten-free diet is one that excludes foods containing gluten, which is a protein found in wheat, rye, and barley. People with celiac disease have an immune response to gluten, so they must avoid it completely. However, there are many people who do not have celiac disease but still experience symptoms from eating gluten, such as bloating, abdominal pain, and fatigue. For these people, a gluten-free diet can help reduce their symptoms.