Fatigue is one of the most common problems for which people seek medical attention. Why is it so widespread? Through years of research, Dr. William G. Crook discovered that chronic fatigue is often linked to the consumption of sugar and yeast, along with other foods to which people can develop sensitivities. Certain nutrient deficiencies, too, can lead to fatigue. Tired—So Tired! presents the doctor's treatment program as well as his research on this important subject.