The number of students eating breakfast in Central Unified School District more than doubled this year after a simple change: Food was moved out of the cafeteria.

Breakfast was already offered to all students, regardless of income. But participation jumped from 16% last school year to 34% this school year after the district bought food carts, packed them with convenient meals and placed them in strategic locations such as school entrances and bus drop-off sites.

The carts allow students to easily pick up breakfast -- such as a sausage sandwich and milk -- without having to step into a cafeteria line. They can eat on their own terms while visiting with friends before class starts.

"Not having the kids walk across campus [to the cafeteria] made a huge difference," said Debi Pollock, food services director for Central Unified.

The new breakfast program is part of an effort by Central to entice more students to eat breakfast, which studies have found is critical to learning.

A study last year by the Harvard School of Public Health, drawing from more than 100 published research articles, found that serving breakfast to children significantly improves their cognitive or mental abilities and enables them to be more alert, pay better attention and perform better on standardized tests.

The same study also said children who eat breakfast are sick less often.

Laurel Ashlock, Central Unified's chief academic officer, said the district will evaluate how well the breakfast program improves student performance, including standardized test scores.

More school districts are pushing breakfast, especially districts where students qualify for free or reduced-price meals but fail to take advantage of them. At Central, about 62% qualify for free or reduced-price meals.

District officials say there are varied reasons why students don't eat breakfast at home, but often it's due to low family incomes. As a result, the majority of students qualify for free or reduced-cost meals at school.

School officials say that even when free breakfast was available in the cafeteria, students often bypassed it so as not to lose precious pre-class time with friends -- and also to avoid having to wake up earlier to leave time for breakfast. It's not as difficult to get students to eat lunch at school, because they're already awake and on campus.

School officials keep trying to boost the rates of breakfast consumption.

Last year Central Unified -- a district of about 14,500 students -- started offering free breakfast to every student. But participation only edged up two percentage points.

It wasn't until the food was taken out of the cafeteria and moved to strategic campus locations this year that the numbers really began to climb.

While the food carts made a huge difference at all of Central's schools, the numbers really shot up at the district's two high schools.

The biggest jump in student participation was at Central High School East campus -- climbing from 10% last year to 41% this year.

It turns out that requiring students to sit and eat in a cafeteria was a big barrier, Pollock said. But having the freedom to eat breakfast on their terms, where they wanted, made all the difference, she said.

The portable meal program is at all of the district's schools. However, Pollock said elementary schools have designated eating areas because younger children require monitoring.

Central Unified heavily promoted the new breakfast program this year.

Fliers were sent home to parents and signs on school grounds tout the free -- and convenient -- breakfast. "Our motto is, 'Free breakfast, every day, every student,' " Pollock said.