TWENTY YEARS ago the choice for Washington area students buying their lunch at school was simple: There was no choice.

Ten years ago it looked as though elementary school children would subsist on fortified food objects, a spin-off of space-age technology and high-school students would simply abandon their lunchrooms in favor of nearby fast food outlets.

Today a second grader at Takoma Park Elementary School may pick a full lunch that includes meat, vegetable, bread, milk and fruit; a soup and sandwich lunch, or a chef salad with crackers, milk, fruit and a choice of dressing. He may have had breakfast at school that morning, too.

School lunch programs in the Washington metropolitan area are alive and struggling to be well received. Increased variety is one element in the campaign to attract and keep young customers. Price is becoming another [TEXT OMITTED FROM SOURCE] as inflation forces up the cost of off-campus hamburgers or pizza.

Still, student complaints persist and not enough are eating lunch at school.

Participation in school lunch programs has been on the decline through the 1970s. Some high schools allow students to leave the campus during the lunch hour (in some others, students leave anyway). Doubts about quality and ingredients of elementary school lunches led many parents to send their children. to school with a packed lunch.

A survey of school districts in the Washington area showed that less than half the high-school students choose school lunch in Arlington, Alexandria, Fairfax County, Falls, Church and Montgomery County. Only the District which serves the highest percentage of government-subsidized lunches, can attract more than three-quarters of its elementary school students.

"We have a closed campus," said Kay Kennedy, supervisor of food services for the Falls Church City schools, "but I still see the students go across the street to a fast food place or the supermarket."

"Our biggest problem is those chuck wagons (vending trucks,)" said Kermit Rosenberg, deputy director of food services for the District schools.

Another reason, authorities say, is that many secondary school students leave school before lunch to participate in work-study programs.

Nonetheless, others pointed to a reversal of this trend.

"Students are finding out that they cannot eat at a McDonalds's or a Gino's cheaply," said one administrator. "The regular lunch at high school costs only 65 cents. The kids are coming back." (The average per-person check at leading fast food chains went over $2 for the first time in 1978.)

"The students are finding out that they cannot beat our prices," added Mary Klato, assistant director of food services for the Prince Georges County Schools. "Even mothers cannot pack a lunch that includes everything we do for 65 cents."

Participation in elementary school programs varies from 81 percent in the District to 47.2 percent in Falls Church. At the latter community's two elementary schools, most students bring their lunch from home. There, as in other jurisdictions, milk is sold for a nominal amount and the non-participating students have the option of buying ice cream.

High school lunches attract from 52 percent of the students in the District to a low of 27.5 percent in Alexandria.

"There are a lot of adults who believe that students, particularly elementary, should not have choices," said Joanne Style, director of food services for the Montgomery County schools. "We find that kids are delighted with the choices."

In Montgomery County and elsewhere cafeterias have been increasing their offerings. Specialty foods such as milk shakes, yogurt and granola bars are served. Salad bars have proven popular Montgomery, Prince Georges and Alexandria have instituted them in some of their cafeterials. Over half the secondary schools in Fairfax County have them.

Fairfax County also reports that its "sack" lunches are very popular. In addition to the Type A meal and salad, students have the choice of purchasing a "sack." It contains a choice of sandwhich, fruit, peanuts or a cookie and milk.

The a la carte lines, where students can choose without having to take all the components of the full Type A lunch, are as controversial as they are popular. Some nutritionists oppose them because the students do not have to order foods from each of the basic four food groups. Others point out that high plate waste in the days when only Type A lunches were served showed that students will eat only what they want no matter what is served to them.

On the other hand, the Alexandria schools discontinued a la carte offerings this year. "So far we have had no complaints," said Beatrice Shenkenberg, asistant director of food services. "The students have not asked for them back."

Some steps have been taken behind the scenes to improve the appeal of lunches and to bring them more in line with current nutrition concepts:

Milk, Arlington and Prince Georges report that they are buying only low-fat or 2 percent milk. (On the other hand, Kay Kennedy, food service supervisor in Falls Church, said her students still prefer whole milk over low-fat by a 7:3 ratio.

Hamburgers. The percentage of fat in hamburgers and ground beef paties has been reduced to 18 or 20 percent in most jurisdictions. Only in Montgomery County does the amount range up to 27 percent.

Sodium and sugar. All the systems report they are taking steps to reduce the amount of sodium and sugar in student meals. Area schools are purchasing canned fruit with light syrup, pushing more fruit desserts instead of pastries and buying turkey or chicken hot dogs because of lower fat content. Montgomery County is preparing more soups itself and using less of the highly salted canned varieties and longer puts salt shakers on tables in the cafeterias.

Additives. Prince Georges has taken steps to use products with reduced amounts of nitrites and has eliminated bacon from its menus. In response to complaints from parents in Fairfax County, next March the schools there will conduct a modified additive-free, preservative-free pilot study in two elementary schools. Planning menus is "quite a challenge," said Penny McConnell, acting director of the food service division. "It is going to be difficult to eliminate all the preservatives and additives. We are becoming very label consious. There is also a time factor involved. It is going to take a great deal of time to use to use all freshly-prepared foods, such as slicing up all those apples."

Baked goods. With the exception of Arlington, all the area school systems report that they bake their own rolls, cakes, cookies and specialty breads. At Falls Church, french-style loaves are baked on days when spaghetti is to be served. Sandwiches are prepared with rye or whole wheat bread as well as white.

Vending machines. None of the area school systems has vending machines for students use in elementary schools. In high schools, with the exception of Arlington, there are restrictions on their use and their contents. Arlington machines sell sandwiches, potato chips, peanuts, packaged pastries and candy. "We are in competition with all the fast, 'junk' food places around here, so we keep all of that in our machines," said George Allin, director of Auxiliary Services for the county.

Fairfax County sells no soft drinks or candy to high school students. The machines in Woodson High School contain ice cream, sandwiches, yogurt, fresh fruit, milk, peanuts or snack crackers. All these also are available in the cafeteria's a la carte line. Machines that sold candy, soda pop and fruit-flavored juices were taken out of the Alexandria schools. The machines in Montgomery schools are plugged in only after school hours for use by those involved in night-time activities. Prince Georges will not allow use of vending machines during the lunch period and forbids stocking them with carbonated beverages, potato chips and fruit-flavored drinks. The District has an outright ban on vending machines. f

The only jurisdiction to serve commercially prepared hot lunches is the District which purchases "meal packs" from Mortons.

With the exception of D.C., all the area's school systems reported that there is some form of advisory council or nutrition committee that can listen to student complaints and make recommendations for change.