Even before Deborah Mazzanti was introduced to the sellout breakfast crowd at Bloomingdale's Friday morning, some of the women were initiated into the regimen of her super deluxe health spa, The Golden Door. Pastries ran out before many of the women were served, but Mazzanti consoled them with, "Think of how many calories you've saved."

Mazzanti has been in Washington since Friday touting her new book, "Secrets of the Golden Door," an extension of the take-home routine she prescribes for Golden Door regulars such as Kim Novak, Bill Blass, Dinah Shore, the Gabors, Barbara Howar and others. Today she is speaking at a Women's National Press Club luncheon.

"Even before the alarm goes off in the morning," Mazzanti told the 99-per cent pant-suited crowd, "squirm in bed to see if you are all there. Visit your body, since a body can become as blighted as a neighborhood."

And just as she advises the $1,250-per-week guests at her spa, she urged the women to stand in front of a full-length mirror for two minutes of strenuous stretching. Nude. "That way you will see it all," she said, and the audience giggled nervously.

The Golden Door plan includes two sessions of exercising, one in the morning and one at "twilight" and "always to the point that you are huffy-puffy - stressing your respiratory ability." To the relief of the crowd she added, "Don't plan to enjoy it. Just get it done."

On the other hand, she pointed out, food should be enjoyed. ("I hate the word diet, it has the word die in it," she said.)

For a non-hassle dinner, she suggests food served from the kitchen in portions suitable to the size of the person. (Most restaurant portions and menus are scaled to a man 5 feet 10; cruise-ship meals for a man 6 feet 8, and weighing 280 pounds, she said.)

Salad, the lowest-calorie item, should be served on the largest dinner dishes. Entrees, on bread-and-butter dishes, and dessert - high on calories - in champagne glasses. No seconds and, to be sure, there should be none prepared. "It makes you eat slower." said. "Extra chew out of the same amount of food has no calories," she said, adding that she's convinced that skinny people dawdle over their meals.

Mazzanti was nourished on health food as a child when such ideas were considered freakish, and only old men and women in tennis shoes, as she describes them, shopped in health-food stores. "The kids changed all that," said Mazzanti. "People used to go to health-food stores because they were ill. Now they go to stay well."

Mazzanti was 4 when her mother was made a vice president of the New York Vegetarian Society. The family was fruitarian as well, eating nothing but raw fruits, vegetables and nuts.

But in the Depression, when such items were not only expensive but rare, the family took off for tahiti, rather than forfeit any such principles.

In Tahiti, her family came in close contact with Prof. Edmond Bordeaux Szekely, who was devoted to the study of applying natural living to an increasingly unnatural culture. He so influenced Mazzanti's family that when they left Tahiti after 4 1/2 years, they organized their lives to spend six months in the city, the rest in a primitive community, including Szekely's health camps. ("I always felt I had a heavy hat on my head when we were in the city," says Mazzanti.)

Aldous Huxley, who had been a men's week guest at the spa, was so taken with the childhood tales of Mazzanti and her brother on Tahiti, they were the inspiration for his book, "Island." Said Mazzanti, "Huxley was the only man to ever say I was witty."

After high school, Mazzanti replaced Szekely's secretary and eventually they were married. In 1940 they opened their first spa, Rancho La Puerta in Baja, Calif., which runs at a capacity 90 guests year round. On their 20th wedding anniversary they opened The Golden Door, first for 12 guests only and now with a capacity of 30, (Mazzanti and Szekely were divorced, and five years ago she married psychoanalyst Vincent Mazzanti.)

Orginally pitched to women, session for men now are so successful, they are held four times yearly. And four years ago The Golden Door started running couples' weeks, with programs planned with Dr. Roy Menninger, president of the Menninger Foundation. (Mazzanti is on that foundation board, as well as on the board of overseers of the University of California at San Diego. She was on President Ford's Committee on Physical Fitness and Health.)

Among those who have attended the couples' weeks are Dr. Jonas Salk and his wife. Francois Gilot and the Vidal Sassons. "People seem to be looking for family support in everything," says Mazzanti.