Students with short lunch periods are less likely to make healthier food choices, according to a recent study.

Researchers at Harvard University found that students with less than 20 minutes to eat school lunches consume significantly less of their entrées, milk, and vegetables than those who aren't as rushed, U.S. News and World Report reported.

"Many children, especially those from low-income families, rely on school meals for up to half their daily energy intake so it is essential that we give students a sufficient amount of time to eat their lunches," Juliana Cohen, lead author of the study and adjunct assistant professor in the Department of Nutrition at Harvard Chan School, said in a statement.

For the study, researchers collected and analyzed data from more than 1,000 students six elementary and middle schools with lunch periods ranging from 20 to 30 minutes, in a low-income urban school district in Massachusetts. They analyzed the students' food selection and consumption by monitoring what was left on their plates at the end of the lunch period.

The researchers found that students with less than 20 minutes to eat lunch were less likely to have a filling meal. They consumed 13 percent less of their entrees , 12 percent less of their vegetables, and 10 percent less of their milk than those who had at least 25 minutes to eat,NDTV reported.

Researchers found also found that there was more food waste among groups with less time to eat.

Waiting in serving lines or arriving late to lunch sometimes left children in the study with as little as 10 minutes to actually sit and eat. The researchers acknowledged that while not all schools may be able to lengthen their lunch periods, they could develop strategies to move kids more quickly through lunch lines, such as by adding more serving lines or setting up automated checkout systems.

"We were surprised by some of the results because I expected that with less time children may quickly eat their entrée and drink their milk but throw away all of their fruits and vegetables," Eric Rimm, senior author of the study, said in a statement. "Not so--we found they got a start on everything, but couldn't come close to finishing with less time to eat."

The findings are detailed in Journal of the Academy of Nutrition and Dietetics.