A dietary cook is a food preparation specialist who works at an institutional kitchen or cafeteria, such as at a school, hospital, medical center, or nursing facility. Your duties in this career are to cook food that meets the particular dietary needs of your clients. For example, at an elementary school, you need to cook food that provides children with the proper nutrition, while at a nursing home, you need to tailor your menu to meet the needs of the residents, taking into account specific medical issues, such as patients who have diabetes or heart disease.