Pharmaceutical preparations and substances for the prevention, treatment and diagnosis of cancer, diabetes, and heart disease; pharmaceutical preparations and substances for the prevention, treatment and diagnosis of neurodegenerative diseases, namely, Alzheimer's disease, Parkinson's disease, and Huntington's disease; pharmaceutical preparations and substances for the prevention, treatment and diagnosis of immune disorders, namely, psoriasis, rheumatoid arthritis, lupus, Chron's disease, inflammatory bowel disease, and multiple sclerosis; pharmaceutical preparations and substances for the prevention, treatment and diagnosis of metabolic, endocrine, cardiovascular, oncological, gastrointestinal, musculoskeletal, mitochondrial, autoimmune, and neurological related diseases and disorders; pharmaceutical preparations and substances for the prevention, treatment and diagnosis of rare genetic diseases; pharmaceutical preparations and substances for the prevention, treatment and diagnosis of Leigh's syndrome, Friedrich's ataxia, lymphangioleiomyomatosis (LAM) and tuberous sclerosis; pharmaceutical preparations and substances for the prevention, treatment and diagnosis of obesity and obesity related diseases; pharmaceutical preparations and substances for the prevention, treatment and diagnosis of age-related diseases; pharmaceutical preparations and substances for modulating the catabolic or anabolic response to nutrients; pharmaceutical preparations and substances for the prevention, treatment and diagnosis of any disease related to muscle wasting diseases and conditions, including, cachexia, sarcopenia and muscle wasting due to prolonged immobilization; pharmaceutical agents affecting metabolism; pharmaceutical agents affecting caloric intake and absorption; nutraceuticals for use as dietary supplements; dietetic foods adapted for medical use; nutritional supplements containing amino acids; pharmaceutical preparations and substances for the modulation of appetite, namely, appetite suppressants and satiety inducers