Any processed, partially processed, or unprocessed substance taken into the body primarily for providing nourishment. In addition, factors such as satisfying social needs, achieving psychological ends, and satisfying hunger govern the selection and consumption of foods. Chosen carefully, foods can provide all of the essential nutrients required for the normal functioning of the human body. In this context, food is necessary to provide energy, to provide structural components for building and repairing body tissues, and to regulate body processes.