Some members of Congress and the president of the School Nutrition Association have said the new standards, which further limit calories, sodium, fat, and sugar, were a burden on schools, and have suggested delaying implementation.
Michelle Obama, whose campaign against childhood obesity championed the stricter guidelines, has said Congress is trying to undo what the campaign has accomplished.
Michael Rock, a Unionville-Chadds Ford school board member, said the district needed to push back more often against top-down policies.
"I have thought for a long time that we are passive recipients of everything that gets imposed on us from the outside," Rock said at the board's June 16 meeting.
The district calculated that under the new guidelines, its revenue would decrease from $2.32 per high school student per day to $1.73, since the students would be buying fewer items.
That represented "a significant financial impact on the food-service operation," said Marie Wickersham, the district's supervisor of food services.
By withdrawing the high schoolers, the district would lose about $38,000 in federal money, Wickersham said, but would more than make up for it in lunchtime revenue.
The district decided to remove only its high school students from the program because they are the most capable of making their own decisions, Wickersham said. "It's our responsibility to teach these kids how to function in the real world," she said.
Unionville High School students will not see a change in school menu items.
The Chester County school district decided to rely on its student-wellness policy as a guide for what to offer its high schoolers. It also still will comply with current nutrition requirements under the Healthy, Hunger-Free Kids Act of 2010, which directs schools to limit fat in milk and offer certain quantities of fruits, vegetables, and whole grains.
New federal guidelines don't fit the needs of the high school community, Wickersham said. For example, student athletes would no longer be able to buy a 20-ounce Gatorade. Under the new rules, the high school could not offer any drink larger than 12 ounces or above a certain calorie limit.
School board member Kathleen Do said she admired the work Obama has done to fight childhood obesity and related diseases. However, she said, the district has seen a decline in the number of students buying lunch at school, from 32 percent in 2011 to 25 percent last school year.
"We may have reached a point of diminishing returns," she said.
Do said the district would continue to evaluate what it offered its students in the lunch line and in vending machines to make sure foods were both healthy and attractive to students.