Having discussed the clinical presentation of dysautonomia resulting from oxidative dysfunction, the role of high-calorie malnutrition is emphasized in this chapter. Some of the symptoms arising from this kind of malnutrition are obvious and some are not. Malnutrition is so frequently considered to be the result of starvation, whereas with excess empty calories the patient often looks quite well, expressing symptoms that are often considered to be psychological in nature. Empty calories, in the modern world so frequently associated with various forms of toxins and even pharmaceuticals, add an enormous physiological stress where the impact is in the brain, heart, and nervous system. Restoration of efficient oxidative metabolism and metabolic flexibility must be induced by the form of therapy chosen. Only recognition of nutrient inadequacy and solving the biochemical lesion can restore health. The role of sugar in the causation of disease is emphasized and modern research is revealing the fundamental association with thiamine metabolism. Thiamine deficiency is increasingly recognized in critically ill patients and its association in cancer, poorly recognized clinically, raises once again the question of the Warburg effect. Some recent manuscripts have revealed that thiamine deficiency plays a part in the etiology of autism spectrum disorder and sudden infant death syndrome.