Today the federal government will issue a new edition of "Nutrition and Your Health: Dietary Guidelines for Americans," a famous publication loaded with astute advice. To wit:

"Eat a variety of foods," "Maintain healthy weight," "Choose a diet low in fat, saturated fat and cholesterol," "Choose a diet with plenty of vegetables, fruits and grain products," "Use sugar only in moderation," "Use salt and sodium only in moderation," and "If you drink alcoholic beverages, do so in moderation."

Over the last six weeks, an informal and secret tour of several federal agency cafeterias was made, with the aim of trying to find out if the government practiced what it preached.

The results weren't impressive. The tenets of the booklet, printed under the aegis of the departments of Agriculture and Health and Human Services, were abused repeatedly and without apology. Only rule six escaped unblemished: It is difficult, perhaps impossible, to buy booze in a federal eatery.

What follows are reviews of four government cafeterias. In all cases, the agency at least paid lip service to a healthy diet, but patrons were encouraged to sin.

The good stuff was inevitably bad for you.

Agriculture Department, Independence Avenue between 12th and 14th Streets NW.

All the ambience of a Nebraska feedlot. Crowded, small and tucked into an airless hallway in the basement, patrons are invited to rub elbows with their fellow employees and sit and eat with them whether they know them or not. The department's Admin Building's cafeteria is one of the last places in town where smokers and nonsmokers are forced to cohabit, a nostalgic twist that injects additional unpleasantness into an already chaotic atmosphere.

The overcrowding could be the result of simple demographics -- the department is very big and the cafeteria is very small. Or it could be geography -- the Mall is long on government buildings, but short on sexy bistros, i.e., there is no place else to eat.

But another reason is that despite the ambience, the food is pretty good. Unlike many other government agencies, the Agriculture Department is not particularly interested in trying to coax yuppies with cottage cheese or high-nutrient glop. The cafeteria's only effort to be cool during one recent visit was steam table quiche -- limp, squishy and almost apologetic. No one touched it.

What the department wants to do is promote the idea that eating is good for you, especially if your food is grown by U.S. farmers. To this end, the cafeteria tempts with "Special Events" -- foot-long hot dogs (three kinds) and chili and beans (sold by weight); "Main Events" -- veal parmesan and the unfortunate quiche, salad; an enormous selection -- grilled chicken and burgers, frozen yogurt (not non-fat and with all kinds of toppings); and individual pizzas (wow!).

A modest $3.88 bought a hot dog (better than ballpark quality), several ounces of chili (excellent) and root beer (a pleasant surprise -- federal employees elsewhere favor Diet Coke and Sprite).

A smoker reading the sports section of USA Today made space, smiled and eyeballed the lunch. "I ordered exactly the same thing," he said. "It's filling if nothing else."

Au contraire. It was terrific.

Supreme Court, 1 First St. NE.

Most of the bosses in this place are well past retirement age, so figure the heartburn quotient must be low. Justice Byron R. White was spotted leaving the dining room with a reasonably satisfied smile, and he is rumored to have helped write the Code of Hammurabi. If White -- who looks terrific -- can thrive at the Supreme Court cafeteria, then it ought to work for the rest of us.

The dining room strives for a "Gay '90s" gaslight look, with a plush, pseudo-velvet decor and red carpets. The accommodations are airy and ample, and the food is even served on plates, not polystyrene. It could almost be elegant except for the Chee-tos/Dorito display flanking the steam table.

The big news at the Supreme Court is that the hot food is decent. You can bet the justices were a little leery of what the barbecued chicken would do to their afternoon arguments (the sauce looks to have been spread on with a trowel), but the black-eyed peas and rice were outstanding. $6.75 with iced tea.

Desserts were meager in the main dining room, and except for the Chee-tos there was almost nothing really fun to eat. For greasy spoon you had to go to a canteen across the hall, where every hamburger ever cooked there seemed to have left an impression. The canteen also had hoagies, nachos, french-fried everything and a whole bunch of nasty snacks and other sweet stuff in plastic bags.

The nicest thing about the Supreme Court cafeterias is that real people can eat there: you don't need an ID, an escort or any other dispensation to get in. And once you're done, you can drift out into the halls to look at busts of justices past and examine an elegant (though somewhat ponderous) exhibit on the drafting of the Constitution.

The most alarming thing about the Supreme Court cafeterias is that the public seems always to prefer the canteen rather than the dining room. Looking at busts of Supreme Court justices may set off a craving for junk food, but that's not the kind of example we're trying to set here. You won't find Justice White pigging out on nachos.

Department of Veterans Affairs, 810 Vermont Ave. NW.

For a Third World flavor, try the basement of the Veterans Administration. Diners coming out of the elevator were welcomed by a table display of scarves, umbrellas, headbands and those little balls that spin around and clack each other. Everything was pink, chartreuse, black or Day-Glo, and nothing cost more than $5. The entire display was run by a street vendor who is not a veteran.

The motif continued inside the cafeteria. A grease trap vented into the dining room, casting a pall that matched the seasick green carpet. A sign advertised fresh fruit juices, but the machine was empty. There was no dessert except gelatin and a couple of stale Danish left over from breakfast.

Another sign offered "fresh grits and oatmeal." The rest of the daily menu: franks and beans; chicken pot pie; canned corn and green beans. One diner, asked to evaluate his swamp-brown plate of beans, paused a moment: "Well, quantity-wise, it's filling."

Those eschewing the steam table could choose from a limited list of sandwiches or pick something from the grill or the deep-fat fryer, most of whose offerings (fried chicken, onion rings and the like) were dried out and withering beneath heat lamps next to the chicken pot pie.

It should come as no surprise that even at 12:30 p.m., the VA cafeteria was half-empty, but the workers were cheerful and solicitous ("Pardon me for reaching in like this, but I've got to weigh your coleslaw."), the salad bar was small but decent, and at $9.88 for two, the price was right.

Next to the plastic knives and forks, the management thoughtfully provided enormous bottles of Tabasco sauce. It helped.

Department of Health and Human Services, 200 Independence Ave. SW.

My tax dollar is paying for a place like this? The penthouse cafeteria at Health and Human Services is clean, modern, high-ceilinged and sun-drenched, a startling contrast to the cramped, windowless afterthoughts that most agencies install in their basement catacombs.

But wait. Everything is not what it seems. The HHS cafeteria is like the high school football team that has the best band, the prettiest cheerleaders, the most modern equipment and the most intimidating uniforms. Except it doesn't win the game.

HHS is trying hard, but hasn't quite made it.

Boosterism begins at the elevator. HHS is interested in HEALTH, and proclaims it in a banner hanging over the entrance to the cafeteria: "Secretary Sullivan's Healthy Menu Program celebrates a winning team . . . good nutrition and regular exercise."

Secretary Sullivan is Louis W. Sullivan, MD, secretary of Health and Human Services and co-author of "Nutrition and Your Health: Dietary Guidelines for Americans." His special during a recent cafeteria visit was spinach salad: with mushrooms, ground-up hard-boiled eggs, bacon bits and shreds of onion. A sample put together by "winning team" members and placed in a plastic display case failed to convince.

Fortunately there were alternatives. With unlimited space and imagination, HHS was able to offer soup, sandwiches (free potato chips!), salad bar (half price on Friday!), steam table, a popcorn machine, hot pretzels, cold cuts and a whole bunch of other stuff.

Unfortunately, the better the food, the worse it was for you. If you declined the spinach salad you could take your choice of beef barbecue, pork barbecue, fried this or grilled that. The cafeteria touted special "zesty barbecued chicken" and "herbed baked fish," but sold both next to the bacon cheeseburgers. Guess what got the customers.

For dessert (displayed in a cooler marked "desert") there was gelatin and unpleasant looking fruit, or you could select from a variety of ice cream bars, cones and sandwiches made mostly from chemicals. The good-for-you jars of trail mix were interspersed with good-to-eat jars of jelly beans, jellied orange slices, candy corn, chocolate drops and the like. Top off your pork barbecue with a handful of malt balls and send your cholesterol on a rocket to the moon. $5.21 with lemonade.