Busy teens stressed over studying or after-school activities say they often skip lunch or dinner with ease.

But when they forgo food a bit longer -- say, 30 hours -- it's another story.

"You just feel exhausted," said Kailan Kinkel, 17, one of 3,000 local teens and 500,000 across the world who participated in an annual fast yesterday to raise awareness of those who are hungry. "You feel dead tired. Your brain doesn't work. . . . It makes you understand why people who are hungry can't get up and go work or get a job."

Kinkel took part yesterday in the 30-Hour Famine, coordinated by the international aid organization World Vision, along with 120 other teens from 10 churches in Northern Virginia. The teens ate lunch Friday and then consumed only water and juice until yesterday evening when they had potlucks at area churches. They spent the day learning about hunger issues and taking part in community service events.

Teens also got sponsors to support them by donating money to World Vision. The fast, which is in its 16th year, raised $11.6 million last year for World Vision's efforts to combat hunger, particularly among children.

"They're obviously not going to know what it's like to starve, but it does give them a taste of hunger," said Jim Harrington, the youth leader of Friendship United Methodist Church in Falls Church, which served as home base for the Northern Virginia teens.

Community service projects included preparing meals for cold-weather homeless shelters, a particularly difficult task while fasting. Other students took to sewing machines to stitch up soft, cheerful jester hats for hospitalized children. About 30,000 of the colorful hats are delivered each year to 15 area hospitals by the organization Glories Happy Hats, said founder Susan Khorsand.

The teens spent the night at the church, staying up late watching movies and gossiping and then collapsing in sleeping bags on the floor.

But education about global poverty was the main focus of the long day. The students watched DVDs about poverty issues. And Harrington showed off a banner on which the students had pressed 30,000 fingerprints in red paint, designed to help them better understand the magnitude of the problem. Experts estimate about 29,000 children die each day worldwide of hunger and hunger-related diseases, he said.

"If I wasn't here, I'd probably be just hanging around the house," said Aumber Singh, 15, who attends Dunn Loring United Methodist Church. "This makes me get out and do something to help."

Adults urged the kids to keep drinking fluids to fight dehydration. "They're other people's children, of course," said Harrington, explaining that the church keeps a nurse on-call, just in case.

Before taking part in the event, most said, they had never tried to go for so long without food. But after participating once, many come back year after year. Jessica Mauck, a senior at James Madison University, has helped organize the event since Friendship United Methodist first got involved seven years ago.

"Hunger is an important issue to God," said Mauck, 21. World Vision is a Christian relief organization, and many teens take part through their church youth groups. "This reminds us that we can't solve the problem by ourselves."

Kinkel, a senior at Battlefield High School in Haymarket, participated along with only one other student from her church last year. She found the experience so moving that this year she recruited 15 teens from Sudley United Methodist Church.

"This really gives it life," she said. "This is real."