Fatigue is the most common complaint doctors hear from their patients. In this User's Guide, a leading health writer explains the three most common fatigue-related disorders - chronic fatigue, chronic fatigue syndrome, and fibromyalgia. Laurel Vukovic describes how our modern diets and lifestyles set the stage for these energy-draining diseases - and she recommends specific eating habits and nutritional supplements that can help readers boost their energy levels.