The potential impact of a school food policy change reducing sweetened beverage and high-fat, salty, and sweet food portions on energy consumption of middle-school students was assessed. Snack bar sales for one school year were obtained from 23 schools. Energy content was calculated for each item and energy savings from reduced portion size was determined. Per student, about 111 kcal per day was purchased; 47 kcal per day was saved when reduced portion sizes were substituted for the large servings. These findings should provide some assurance that changes in food portion sizes in school food environments could impact energy balance.