WASHINGTON — The U.S. Department of Agriculture has followed through on a pledge made last year to make permanent the current flexibility that allows schools to serve larger portions of lean protein and whole grains at mealtime. The U.S.D.A. first granted flexibility in the program in December 2012, acknowledging difficulties encountered by states and schools in serving meals that fit within the weekly minimum and maximum serving ranges for grains and meat/meat alternates as established in standards announced in April 2012 and implemented with the beginning of the 2012-13 school year.

“Earlier this school year, U.S.D.A. made a commitment to school nutrition professionals that we would make the meat and grain flexibility permanent and provide needed stability for long-term planning,” said Kevin Concannon, Agriculture Undersecretary for food, nutrition and consumer services. “We have delivered on that promise.”

The U.S.D.A. said it worked closely with schools and parents during the transition to healthier breakfasts, lunches and snacks. Following feedback from consumers, the U.S.D.A. implemented several updates to school meal standards, including additional flexibility in meeting the daily and weekly ranges for grain and meat/meat alternates, which has been available to schools on a temporary basis since 2012.

“S.F.A.s (school food authorities) reported that for both grains and meat/meat alternates, some popular products are not yet readily available from suppliers in the wide ranges of serving sizes needed to meet the grain and meat/meat alternate weekly maximum requirements,” the Food and Nutrition Service of the U.S.D.A. said in a Jan. 3, 2014, notice published in the Federal Register. “Additionally, S.F.A.s have reported that they are experiencing challenges with student acceptability of new items and smaller servings of items on their menus.”

The F.N.S. noted in the Federal Register that the added flexibility on weekly maximum servings of grains and meat/meat alternates will benefit S.F.A.s “who may continue to rely on prepared foods or recipes that ensure compliance with daily and weekly minimum quantities but may exceed weekly maximums in some weeks. However, because the meal patterns’ weekly calorie requirements remain in place, the added flexibility on grains and meat/meat alternates is unlikely to have a significant effect on the overall quantity of food served, the cost of acquiring that food, or the nutritional profiles of the meals served.”

The final rule will take effect March 4, 2014.

The School Nutrition Association applauded the U.S.D.A.’s announcement.

“School Nutrition Association members are pleased that U.S.D.A. has provided this permanent fix, acknowledging the need for greater flexibility in planning well balanced school meals,” said Leah Schmidt, S.N.S., president of the S.N.A. “With school nutrition professionals already planning menus and inventory for the 2014-15 school year, eliminating the grain and protein limits is a key step to providing healthy menus that appeal to students.”

Last month, the U.S.D.A. awarded $11 million in grants to help schools purchase equipment to make preparing and serving healthier meals easier and more efficient for school food service professionals. And in November, the U.S.D.A. issued an additional $5 million through the Farm to School grant program to increase the amount of healthy, local food in schools.

Also during fiscal 2013, the U.S.D.A. said it awarded $5.6 million in grants to provide training and technical assistance for child nutrition food service professionals and support stronger school nutrition education programs, and plans to award additional grants in fiscal 2014.