Nutrition plays an important role in health and disease, both in prevention and treatment. Increasing emphasis is being placed upon nutrition as a therapeutic tool to decrease the morbidity and mortality associated with obesity, hypertension, coronary artery disease, and cancer. Adequate nutrition should be a concern for all health care workers because of its impact on the overall health of patients. Health care professionals should be familiar with the essentials of nutritional assessment and basic nutritional requirements and be able to improve their patients' care in the face of nutritional deficiencies or excesses.