Sodas and sports drinks will soon disappear from Arlington public high schools' vending machines, under guidelines the School Board approved Thursday night requiring that machines available to students sell only beverages or snacks that meet certain federal nutrition standards.

The 4 to 1 vote came after a year and a half of discussion and is part of a trend among school districts to try to combat childhood obesity and other health problems.

Arlington students currently can purchase such snacks as candy, chips and soda from vending machines in high schools. The machines are turned off during breakfast and lunch but are open at other times.

"It was really kind of catch as catch can, based on what the principal thought the kids wanted," said Mary H. Hynes, vice chair of the board, who voted for the new rule. That food, she added, tended toward "what we all think of when you stop at the 7-Eleven and you want to grab something real quick."

Arlington middle and elementary schools make vending machines available only to teachers during school hours. Teachers' machines are not affected by the new rule.

Under the new guidelines, vending machines will be allowed to sell water, 100 percent fruit or vegetable juice, drinks containing at least 25 percent juice with no added sweeteners and reduced-fat milk. The district also will specify fat and caloric content and nutrient levels of snacks sold in vending machines.

Vending machine contracts in county schools will be negotiated this fall, and the new guidelines will be specified in new agreements, said schools spokeswoman Linda Erdos.

With its new restrictions, Arlington joins other area school districts that have toughened guidelines on what can be sold in schools. As of this fall, the District allows only 100 percent fruit juice and water to be sold in vending machines. Montgomery County schools' vending machines cannot sell drinks containing less than 50 percent fruit juice until after the end of the school day. Fairfax County sells only water and 100 percent fruit juice to elementary school students and only drinks with at least 25 percent fruit juice to middle- and high-schoolers. In Loudoun County, snack vending machines in high schools stock food at the principal's discretion, and they do not operate during breakfast or lunchtime.

Hynes said she had been pushing for guidelines for a long time, but more parents had come forward in the past year. "As the obesity issue came up, as the movie 'Super Size Me' came up, there's a growing issue across the country for school boards to regulate it," she said.

Several parents hailed the new rule.

"Arlington public schools provide the best academic opportunities for our students, and we should provide the same when it comes to nutrition," said Abby Raphael, president of the Arlington Science Focus School's PTA. "We teach kids about healthy living, but if we're not seeing nutritional food in the schools, then what message are we sending?"

But Frank K. Wilson, the dissenting board member, said he believes healthful eating should be encouraged but not regulated.

"I think if you're trying to change the culture of people drinking sodas and sports drinks, then what you need to do is change the culture through the curriculum," he said. "You teach children about nutrition, and then you leave it up to the individual."

A recent Government Accountability Office survey of 656 schools participating in the federal school lunch program found that 90 percent of public schools sell such snacks as candy, soda, pizza and popcorn from vending machines, the cafeteria and school stores. The study found that 75 percent of public high schools and 65 percent of public middle schools had exclusive soft drink contracts, up from 26 percent of public middle schools in 2000.

Still, the trend seems to be moving toward tighter regulation. The American Academy of Pediatrics has recommended that "sweetened drinks" be eliminated from schools; a policy statement by the National School Boards Association recommends that schools offer "healthy food and beverage items"; and last week California Gov. Arnold Schwarzenegger (R) signed a bill barring carbonated sodas from public high schools.

Although Arlington school officials said sales from the district's 46 vending machines account for only a small fraction of revenue and did not affect the decision, many U.S. schools struggle to balance limiting junk food with losing an important source of money if they do.

Staff writers Maria Glod, Ylan Q. Mui, V. Dion Haynes and Rosalind S. Helderman contributed to this report.