SAN DIEGO -- Be of good cheer, dieters, there really is a fairy godmother. Her name is Joanne Guy, she resides in San Diego, and she's developed a service to make dieting a piece of cake -- if you'll pardon the expression.

"Doorstep Diets" is the name of this unusual business. For a reasonable fee, one may have a 900-, 1,200-, or 1,800-calorie-per-day diet plan delivered to home or office between 6 and 9 a.m. up to six days a week.

Clients have a choice of three meals or just lunch and dinner, and the food is packaged in microwave-ready containers (it can be transfered to other dishes for conventional oven heating). "The recipes are so numerous," according to Leonard Temko, 75, a retired president of a New Jersey electronics firm who has been using the service off and on for over a year, "not a single main dish is repeated within six weeks."

While half of the clients are dieters, the other half are people too busy to prepare three healthful meals a day. Most important, after three years of trial and error, the kinks have been worked out and Guy is ready to franchise.

The nutritionally balanced program -- all items on the menu are low in cholesterol, sodium, sugar and fat -- is approved by the American Heart Association. A dietitian is on call to review menus and answer questions.

But lest you think you'll be suffering salads rather than sauces, dietetic dairy cream instead of satisfying desserts, check again. Doorstep Diets offers the most consistently scrumptious meals of any diet plan this chronic dieter has ever researched.

Within the health and caloric requirements, Guy and her staff prepare spicy gourmet food from a wide range of cuisines including Middle Eastern, Italian, French, Spanish, Mexican and Greek.

One day the main lunch entree was tuna with a dill sauce, creamy and rich tasting. For dinner, beef bourguinonne was simmered for hours until the herbs, wine and meat juices combined into a sauce that would be at home in any fancy restaurant. Dessert was a moist chocolate devil's food cake -- albeit a small wedge, but big enough to fool the senses into satisfaction.

During an additional five days of trying the 900-calorie plan, this reporter was served among other treats, a crusty rich wedge of Italian spaghetti pie, a sensational whole-wheat enchilada (spicy, filling and cheesy), a cinnamony luscious Greek pastitsio, a silky delicately seasoned oriental chicken with plum sauce, and a gooey delicious sloppy joe.

The only failure was a dry, tasteless fish roll. "We have a problem with fish because it's hard to reheat without drying out," said Guy.

Otherwise, it was five days of crisp well-seasoned vegetables and starches, salade varie'e with a different dressing daily, and with the yogurt, muffins and wedges of desserts, just enough sweets.

After years of dieting on dreck, one can only ask "How?"

"The secret," said Guy, "is twofold -- substitutions and small portions. The only difference between the 900-calorie plan and the 1,800, is the dinner roll and larger portions."

A lower calorie neufcha~tel is substituted for cream cheese, both as a spread and in sauces; fruit pure'es rather than sugar are used for sweetening; a powdered butter substitute called "Butter Buds" thickens sauces ("When you add water, it's like melted butter," said Guy, "but you can't use it for saute'ing or in baked goods); ground turkey is often used instead of ground beef; and lowfat rather than whole milk is the norm.

The second part of the secret is portion control. "A recipe for six will serve 12," Guy said.

But one is impressed with the large portions, even for the 900-calorie dieters. There's no sense of deprivation, in fact the 1,800-calorie portion would satisfy many normal appetites.

But the small portions mean that clients' appetites must be appeased in ways other than volume.

"Presentation is very important," said Guy. "The whole meal must be color-coordinated and packed attractively with garnishes and sauces."

Moreover, some dishes like the fish don't taste good the next day, so foods that reheat well must be used. "Steaks, hamburgers and pancakes aren't good the next day either." Also, Guy chooses food with universal appeal. "Not everyone loves brussels sprouts," she said.

Guy has developed a number of her own recipes, but most are adapted from low-calorie, high-quality sources such as Weight Watchers, Redbook's "Wise Woman's Diet," "The Dieters Cookbook," Better Homes and Gardens "Secret of Salt Free Cooking," Gourmet Magazine, and the Pritikin diet.

Each meal is well conceptualized. The color, content and calories in every menu are planned well in advance.

Breakfast, while never boring, provides the least variety. "Out of six days," said Guy, "muffins are served on four." Eight different kinds, including whole-wheat almond, banana, blueberry bran, pumpkin nut and corn, are a muffin maven's fantasy and Guy is still experimenting with new textures and flavors.

Other breakfasts include homemade cre~pes filled with cottage cheese and topped with fresh fruit pure'e, baked apples stuffed with granola, and breads such as zucchini and pumpkin and bagels with neufcha~tel cheese.

Rounding out the meal are local lowfat fruit or honey vanilla yogurt and fresh fruit. The calorie breakdown for Doorstep Diet's breakfast is approximately 250 for the 900-calorie plan, 300 for the 1,200 and 500 for the 1,800 plan.

Lunch usually consists of a hot main dish and fresh fruit. A spinach cheese pie using rice and cottage cheese as fillers, was sensational in both consistency and taste. Another winner was the macaroni crust pie -- crunchy, cheesy and filling. Turkey puffs, tuna turnovers, and vegetable lasagna are other main luncheon dishes. Calories: 300 for 900-calorie diet, 350 for 1,200 and 600 for 1,800 diet.

Dinner entrees are always accompanied by a fresh salad, and for the 1,200 and 1,800 dieters, a whole-wheat roll. Homemade salad dressings are tasty and varied. Some of the outstanding entrees include chicken florentine on a bed of spinach with a neufcha~tel sauce, chicken parmigiana with spaghetti, potato moussaka, and sole with walnuts.

This is also the time for sweet tooth sufferers. Cookies, cakes and pies are served in wedges, slivers or slices depending upon your calorie requirement. The dinner calorie count is 350 for 900-calorie menu, 550 for the 1,200 and 700 for those on an 1,800-calorie plan.

For vegetarians or picky eaters, substitutions are available. When beef is served there's always an alternative -- for example, chicken couscous or falafel with couscous and vegetables. "One lady hates yogurt so we give her cottage cheese."

Guy and her band of helpers -- two others in the kitchen and three delivery men ("One, who's been with me from the first," said Guy, "is a retired man from Pennsylvania who didn't want to just go surfing.") -- work from 5:30 a.m. to 2:30 p.m.

The trickiest part of the operation is organization -- seeing that the 50 regular clients get the right calorie diet, any substitutions, and the right portions. The actual packing takes two hours of concentration.

Nothing in Joanne Guy's background prepared her for the travails of the food business.

"I got into it out of ignorance," she said. "If I'd known anything about the business I probably wouldn't be doing this. My husband thought I was bonkers, that it was just another of my wacky schemes to get rich without having a full-time job."

Born in Boston, Guy arrived in San Diego eight years ago after working and trekking through the Middle East and Africa with her husband, Glen. A degree in French, and a masters in English led to a teaching position at San Diego State University, followed by a job as a technical writer for General Dynamics.

The birth of her second child produced a need to lose a few pounds. "I would work all day, run home and try to prepare dietetic meals while taking care of the kids (a girl now 3; a boy, 2)," she recalled. "While commiserating with a friend in the same predicament we realized there must be a lot of people needing to lose weight, but too busy to prepare proper meals."

The next six months were a nightmare of coming home from work, feeding and caring for the family, cooking until midnight for the eight original customers, sleeping, rising at 4 a.m. to deliver the meals, going to work and then starting all over again.

After six months, Guy's partner dropped out. Guy moved to a bigger space, quit her job and began Diet Doorstep in earnest.

The only advertising was in a small local women's paper. "Most of my business came from referrals, and still does," she said, "and we showed a profit from the beginning."

Today, prices are $70 a week for three meals a day on the 900-calorie plan, $80 on the 1,200 calorie and $93 on the 1,800-calorie plan. For six days, prices are $84, $96 and $110 respectively. Lunch and dinner plans are about $10 less in each category.

Guy is presently in the process of computerizing all records, menus and recipes. Each recipe will be analyzed for 19 essential nutrients such as protein, fiber, fat, cholesterol and carbohydrates.

"When this is done, it will enable us to go into hospitals, home health care, and meals for people on restricted diets," said Guy about future plans.

Meanwhile Doorstep Diets has a committed following of satisfied dieters.

Temko is a twice-divorced current bachelor who uses the service mainly for convenience. "In the beginning I lost 20 pounds," he said. "Now I just like the wholesome healthy food that's never boring."

"If you have to diet you don't want cottage cheese every day," said Marie Kollmeyer, 44. The secretary in a local children's center lost seven pounds the first two weeks on 900 calories a day, and said "the program is going to save my life."

Ad executive Rick Wise, 37, wanted to lose weight, but his "willpower was not the greatest." He lost 29 pounds on the plan alternating from 900 to 1,800 on different weeks over a year's time. Now he's on it because it's convenient and healthful. "It's a reasonably priced way to lose quickly and sensibly and to maintain the weight loss."

Here are some recipes adapted for Doorstep dieters:

SPINACH CHEESE PIE (Spanakopita) (6 servings, 340 calories each)

FOR THE CRUST:

1 cup unsifted all-purpose unbleached flour

1 cup unsifted whole-wheat flour

1/3 cup margarine

6 tablespoons water

FOR THE SPINACH FILLING:

1/2 pound spinach washed, thoroughly dried and torn into small pieces

1/2 pound feta cheese, crumbled

3/4 cup low-fat cottage cheese

1 medium-size onion, chopped ( 1/2 cup)

1/2 cup uncooked long-grain rice

2 eggs, slightly beaten

1/4 cup chopped parsley

1/2 teaspoon dill weed

1/2 teaspoon pepper

Prepare crust by combining flours in a small bowl. Cut in margarine with fingertips until mixture is crumbly. Add water, stir lightly with fork until soft. Form dough into a ball. Using a little more than half the dough, pat into a 12-by-8-inch rectangle. Place into bottom of 11 3/4-by-7 1/2-by-1 3/4-inch baking dish. Bake at 350 degrees for 10 minutes or until golden brown. Reserve remaining dough.

Prepare filling by combining the rest of the ingredients in a large bowl. Mix until well-blended. Spoon into baked crust. Set aside.

Pat remaining dough into a 12-by-8-inch rectangle. Place over top of spinach mixture. Bake at 350 degrees for 35 minutes or until golden brown.

From Family Circle Magazine MACARONI CRUST PIZZA (7 servings, 318 calories each)

FOR THE CRUST:

2 cups elbow macaroni (7 ounces)

2 beaten eggs

1/2 cup shredded monterey jack cheese

1/4 cup grated parmesan cheese

1/4 cup milk

1/2 teaspoon dried basil, crushed

1/2 teaspoon dried oregano, crushed

1/4 teaspoon pepper

FOR THE FILLING:

1 beaten egg

1 cup cream-style cottage cheese, drained

8-ounce can pizza sauce (2 cups)

1/4 cup thinly sliced scallions

1/4 cup finely chopped green bell pepper

1/4 cup sliced pitted ripe olives

1 cup shredded monterey jack cheese

To make the crust, in a large saucepan cook macaroni according to package directions; drain well. In a mixing bowl, combine the 2 beaten eggs, jack cheese, parmesan cheese, milk and seasonings. Add drained macaroni and mix well. Form mixture into a "crust" in a greased 10-inch pie plate or a greased 11-inch quiche dish. Bake in a 375-degree oven for 10 minutes.

To make the filling, combine in a bowl the egg and drained cottage cheese. Pour on top of macaroni crust. Pour pizza sauce over top and arrange scallions, green pepper and olives on top. Sprinkle with the cheese. Return to the 375-degree oven for 10 to 15 minutes or until heated through. Let stand for 10 minutes before serving.

From Better Homes and Gardens CHICKEN SUPREME (4 servings, 185 calories each)

FOR THE DRESSING:

1/2 cup diced celery

1/2 cup shredded carrot

1/2 cup sliced mushrooms

1 clove garlic, crushed

1/2 teaspoon mixed dried herbs (sage, oregano, etc.)

Freshly ground black pepper to taste

1 1/2 cups canned or homemade chicken broth or consomme

Whites of 2 large eggs

2 slices whole-wheat bread, diced

1 tablespoon chopped fresh parsley

Vegetable oil spray

FOR THE CHICKEN:

4 boneless, skinless chicken breast halves, 4 ounces each, pounded to 1/4 inch thick

1 1/4 teaspoons cornstarch

Chopped fresh parsley

Celery leaves for garnish

To prepare the dressing, place celery, carrots, mushrooms, garlic, herbs, pepper and 1/2 cup broth in a saucepan. Simmer 5 minutes over medium heat until vegetables are just crisp-tender.

In a large bowl, with fork or wire whisk, beat egg whites until frothy. Stir in vegetable-broth mix, bread and parsley until thoroughly blended. Lightly spray 8-inch square pan with vegetable oil spray. Spoon in dressing and bake at 350 degrees for 20 minutes.

Reduce oven temperature to 325 degrees. Place 1/4 of dressing on each chicken piece. Roll up to enclose dressing and secure with wooden picks. Place in a shallow baking pan. Cover with foil and bake 25 to 30 minutes or until chicken is cooked through.

To prepare sauce, blend in a small saucepan the cornstarch, a few grains of pepper and remaining 1 cup of broth. Bring to boil over high heat, reduce and simmer 1 minute. Spoon some sauce over chicken. Serve the remainder in a serving bowl. Sprinkle chicken with some chopped parsley and celery leaves.

WHOLE-WHEAT MUFFINS (Makes 12 muffins)

Each muffin has 200 calories.

1 cup all-purpose flour

1/2 cup whole-wheat flour

1 tablespoon double-acting baking powder

1/2 teaspoon salt

2/3 cup firmly packed brown sugar

1/4 teaspoon nutmeg

1/2 teaspoon cinnamon

1 cup skim milk

1 egg, slightly beaten

1/3 cup vegetable oil

2 cups crisp whole-wheat cereal flakes

1/4 cup coarsely chopped nuts (walnuts, pecans)

In a medium-sized bowl, mix flours with baking powder and salt. In a small bowl, combine brown sugar, nutmeg, cinnamon, milk, egg and oil. Add to the flour mixture and mix just until dry ingredients are moistened. Stir in cereal and nuts. Pour into greased muffin pans. Bake at 400 degrees for 30 minutes, or until wooden toothpicks inserted in center comes out clean