Standardized state testing ended this week for most Philadelphia public schools, and, sadly, so did a push by principals to make sure students ate breakfast.

Research shows that students who eat breakfast perform better academically. So, it makes sense that principals would try to give their students an edge during testing periods - especially when they have a personal stake in the results. But what about the rest of the year?

Too many students come to school with hunger pains every day - not just during the testing cycle.

A Public Citizens for Children and Youth survey of 35 Philadelphia elementary schools found that 63 percent changed their policy to make sure kids ate breakfast during test week.

Students were taking the Pennsylvania System of School Assessment. Besides measuring academic progress under the federal No Child Left Behind law, the test results are used to judge principals' performance. So, during test week, some principals took extra steps to provide breakfast at their schools.

That is in stark contrast to a normal school day, when more than 100,000 city students skip a chance to eat a free breakfast at school. Too little has been done to change that.

Every city school serves breakfast, and all students are eligible for the meal, regardless of income. Yet, only about 51,000 of the 165,000 district students take advantage.

Some likely get breakfast at home, but in a largely poor school district, many probably do not.

To get more students to eat breakfast at school, the district this year began offering free meals to all students. That has accounted for a 9 percent increase.

During testing week, principals made it even easier for students to get fed by serving breakfast in classrooms during the first period. Breakfast usually is served in the cafeteria before the first bell.

The temporary change in serving breakfast underscores a structural problem in the program. It lacks uniform guidelines. How breakfast is served is decided by each principal. That's a huge factor in participation.

More kids eat breakfast when it is served in the classroom. Principals say that cuts into instruction time. But other districts have found ways to make it work. The Newark, N.J., district uses that approach, and it has the highest breakfast participation rate in the country.

With no mandate from central administration, however, Philadelphia principals are left to develop feeding programs as they see fit. Many are unwilling to restructure the school day to serve breakfast. Many parents are unaware of the free-breakfast program.

That must change. If schools chief Arlene Ackerman wants to improve student performance, she should begin by making breakfast a priority for healthy learning. That means giving principals their marching orders, and holding them accountable. Add breakfast service to their job evaluations, if necessary.

Michael Masch, the district's chief business officer, says that if the district can make breakfast a priority during testing, it should be able to do it all the time. He's right.