Background: A recurring problem in medical institutions is patients not always receiving food meeting their nutritional and medical needs. A proposed contributing factor is non-inclusion of dietitians in food service staff. Recently, positions for food service dietitians in hospitals were created. For the newly defined role of "Food Service Dietitian", comprehensive training courses were developed (70 dietitians participated). Objective: To examine the impact of the addition of the role of a "Food Service Dietitian" in medical institutions on suitability of foods served, food costs and food waste.Methods: A three years (2014-2017) national case study to examine the new role's impact was carried out, in 18 hospitals, nine of which employ a food service dietitian (intervention), and 9 without (control). The number of nutritional analyses of menus was checked, as was the extent of kitchen staff training, and how often night meals were served for all patients. Data were gathered regarding food costs and waste with respect to food distributed to staff and patients. Food costs savings and waste reduction were calculated, based on reduction in provision of unnecessary meals, at a cost of 18 NIS per day per meal.