LAST FRIDAY evening the Wheaton High School Knights, a well-disciplined football team, knew their assignments and executed them perfectly. Minutes after they took the field, a solid wall of food -- featuring 45 pounds of Roast Beef, supported by such stalwarts as the Salad Twins, Potato and Macaroni, and Chunky Coleslaw, had given way. Pausing only for several swigs of soda pop, the Knight's went back on the offensive: They quickly decimated a trio of angel food cakes with strawberries, brownies and a cake decorated as a football field (with the correct line markings).

By most meal clocks it shouldn't have been half-time, but the Knights were in the end zone and the game was over.

The real game wouldn't be played until the next evening, but Wheaton's team is fortunate to have two major events each week. The night before the game a team supper, organized and executed by parents of the players, is held. According to Jo Anderson, hostess for the feast, the weekly gatherings "are great for the kids. It gives them an evening together, a chance to relax before the game."

It also gives parents a chance to play a stronger supporting role in their children's athletic program. Joanne Elie, who has played a major part in organizing the dinners this season and last, explained they began in part because the players wanted to be together and the cost of weekly dinners at a restaurant quickly mounted up. Under the Wheaton plan five or six different parents shoulder the expenses each week, though a few more may become involved in meal preparation. The cost is $15 to $20 per parent, but this expense only comes once a season.

"There are 55 kids on the team," Elie said, "and by the end of the season about 50 parents will have been involved in these meals. The soccer team has been going it this year, we did four or five for the baseball team last year and the JV football team did one two weeks ago. It has kind of caught on."

A few weeks ago, the parents stepped aside as the school's 24 pom-pom girls and 12 cheerleaders prepared a covered dish supper that was served in the school cafeteria.

Usually, however, the dinners are held at a sponsoring parent's home. Early in the season the crowd can flood into a back yard. The Andersons' split-level was crowded. With parents, coaches and Wheaton principal Aaron Wilcox on hand, the number of people served approached 80.

Wilcox kidded the players, saying this was the second meal he had taken with them because he had seen some of them in cooking class earlier in the day. "They like to eat," he said. "But they're good cooks, too," responded one of the parents.

But most of the conversation among the adults focused on the boys' eating talents. Elie, whose son Tom plays cornerback, shares coordinator duties with Barbara Horan, whose son Jim is the team's quarterback. "We make sure the menus and the supplies are set," Elie said. "We've learned that the simpler we keep things the better off we are. The menu is different each week. They like that.The secret is to have it ready when they hit the door. The boys do a fine job of cleaning up and there are scarcely any leftovers."

One of her proudest moments as a quartermaster came when she ordered 97 pounds of chicken for a dinner earlier in the season. At meal's end, four pieces remained."I'll bet the boys didn't see them," joked another parent.

In addition to the beef, cooked and cut to fit 180 sandwiches, last Friday's menu included six pounds of sliced tomatoes, 15 pounds of potato salad, eight pounds of coleslaw, plus condiments and desserts. The usual beverage allotment is 15 gallons of punch, but as this meal was in honor of the coaches, someone had donated the soft drinks.

Like most good teams, the Wheaton parents have a secret weapon. The proprietor of Germantown Meats, Jim Poole, has a son at the school and he, according to Elie, had done yeoman work for the dinners. The week previously, for example, he had sliced the ingredients to make up 140 submarine sandwiches.

But the parents work too. Claire Cox, whose son Steve is a cornerback, did the coleslaw. "When I use a blender," she said, "all I get is mush. So I chopped for quite a few hours last night." The result was a crisp, fresh tasting salad that was popular although she had decorated it with green pepper rings. "My husband said when they see the green peppers, nobody will eat it, but I put them on anyway."

The food tastes of the young athletes seemed to be keyed to quantity.

"The problem is stopping them," said Anderson. They eat so much they've got to get a balanced meal." Another mother cut in: "Mike gets a balanced meal in a single sandwich."

"They're hungry all year round, not just during the season," added Anne Mulains, whose son Gary plays offensive and defensive tackle. She made a face. "They don't say 'hi' or 'how are you' when they come home, just 'when are we going to eat' or 'what are we having for dinner.' Most anything is acceptable, but vegetables -- especially cooked vegetables -- aren't much more popular than a badly thrown pass."

Nonetheless Mary Murphy, mother of defensive tackle Mike, had made potato salad "the way I like it." Her's contained onions, celery seed, chopped pickle and eggs, mustard and mayonnaise. Anne Mulains' had celery, onions, celery seed, salad dressing, mayonnaise and chopped egg. They were of different consistencies and tastes, but both were first string products and when the players arrived they showed both equal attention.

"They eat a lot," said Anderson's husband, Harry, "but they're not fat. They're just big."

And so they were. Pausing to autograph a football for the coach, they came into the dining area one by one. The only word spoken as the first half-dozen went past the piled up sandwiches was by one player who asked, "can we take two?" He could and did.

Within 12 minutes they had all been served and some were drifting back for seconds.

"If we win tomorrow night," explained one parent, "the team will be in the state playoffs. That means they'll play two extra games."

"That means two more meals!" said Elie in mock despair.

But she, like the others, was cheering as Wheaton came off its roast beef dinner and ate up Einstein High 22 to 0 on Saturday night.