The authors developed "DIET", a computerized system preparing dietary prescriptions in clinical settings. "DIET" has the ability to calculate the nutritional requirements and to produce daily menus of patients automatically. Also, it serves as an electronic medical and dietetic record and it can produce daily reports regarding portions, quantities and cost of meals. The authors also conducted a preliminary evaluation of the system by comparing the design of nutritional plans for 135 patients using "DIET" versus the customary manual methods. Its use resulted in a decrease of the error percentages, concerning appropriate food choices, data recording and calculations of daily nutrient requirements; from 12% to 1.5%. Additionally, there was a reduction by 50% of the time required to obtain and process data as well as design a patient's menu. "DIET" implementation resulted in error decrease and thus in improvement of menu planning, accuracy and recovery of data and decreased the time spent on menu planning.