Book excerpt: Gluten intolerance (celiac disease) is a genetic disorder that affects almost 3 million Americans, with symptoms that run the gamut from diarrhoea, weight loss, and malnutrition to isolated nutrient deficiencies that don't produce gastrointestinal symptoms. And although popular wisdom holds that celiac disease is strictly a problem tolerating wheat, sufferers also have difficulties with rye and barley. Testing for celiac disease is a fairly simple process, but it can be extremely difficult to diagnose-and today the only truly successful treatment for it is a strict gluten-free diet for life. The Complete Idiot's Guide to Gluten-Free Eatingtakes post-diagnosis readers on to the next stage of the rest of their lives-dealing with the day-to-day challenge of eating gluten free. It's a practical guide that offers tips, advice, and information.