It's a question that weighs on any body-conscious mind at one time or another. What do fashion models eat? How do the skinny models who fill the pages of Vogue and Harper's Bazaar stay that way? On an average work day, at least, while they are confined to a photographer's studio for long hours of being made up, coiffed, dressed and photographed, there is a chance to observe what passes through the lips of top New York models.

A magazine spread can take a day to shoot, and longer editorials or catalogues can keep models in the studio eight hours a day for a week. And even they have to eat. Fortunately for today's model, what used to be a trip to the deli for yogurt if you were dieting and sandwiches if you weren't has recently become a specialty service for a handful of New York caterers: providing studio lunches geared toward feeding the model figure.

"There was always some kind of studio lunch," says Patrick de Marchelier, a New York photographer. "You could find a restaurant that would prepare something for take-out but now it is more organized, and more pleasant than eating a sandwich." DeMarchelier wants to eat well. A studio lunch must be healthy, varied and not fattening. He looks to the new caterers for meals that are "quick" so he can get back to work and will avoid a meal that is "so heavy you fall asleep after lunch."

What these studio caterers offer is a lunch prepared for the special needs of a model struggling to maintain a slim figure and avoid unhealthful or fattening foods. Also considered are the conditions of a studio -- no kitchen or a mere kitchenette to work in, racks of expensive clothing that must be protected from food and beverage spills, and limited table space. Greasy foods and spraying soda cans are almost guaranteed to stain clothes, and big gooey sandwiches make a mess of meticulously applied makeup. The most popular caterers provide further service: they deliver. This saves the time and trouble of dispatching someone who is needed on the shoot to get lunch.

Feeding the model figure isn't easy. The good news, according to models and their agencies, is the apparent end of binging and starving, liquid diets and celery sticks for most health-conscious New York models. The diet is well-rounded and surprisingly filling.

"Models eat a lot," said Maxine Tall, head booking agent for the New Faces division of Elite, a top New York modeling agency. As new young models sign with Elite, Tall establishes diet guidelines for each model to help them lose or maintain weight. "All models need and have some type of program. I advise them on food and exercise, tell them what to avoid, how to measure amounts of food."

Tall stresses a vegetarian approach (lots of brown rice) but finds that "after a while models fall into eating programs that suit their needs, join health clubs, watch weight and stay in shape. It's basically common sense."

According to Tall, "we are more health-conscious, conscious of what we eat. The national trend is reflected in the modeling business. The models have requested healthier lunches and have gotten them."

Judy Casey, a photographer's representative in Manhattan, cites the important qualities for a studio caterer: "He brings good food that's always varied; he's on time and good about details (the models want both Evian and Perrier); and he's able to be available at the last minute." Casey bases what is ordered on who is working in the studio. Maybe the photographer is a vegetarian.

"Pick a creative caterer who provides a lunch that's well-rounded and not boring," says Casey. "If the food is lousy, people get annoyed and complain. Then the work is interrupted. The only thing that could be worse is to hear the words, 'Let's order from the deli down the street.'"

"A lot of these people eat at the finest restaurants in the city and are used to good food. We try to keep our menu current and serve comparable foods," said Peggy Gibbons, the owner of Food Squad, a four-year-old Greenwich Village catering firm. Gibbons specializes in studio lunches, the result of a need she discovered during her own days as a model. "A good lunch is a must, the deli is dreaded." Her meals average about $12 per person, more than a deli, but the menu is geared toward the studio conditions: not too messy, easy to serve and eat, light, fresh, seasonal, and packaged in the "nicest disposable containers available."

The menu combines a lot of vegetables, greens, chicken, seafood, pasta and grains. "It's very healthy and leans towards vegetarian tastes."

Gibbons also has a boxed lunch so people on a shoot may eat when they are ready without a table or plates. This is helpful in a busy studio as well as on location when trailers are crowded with clothing and makeup tables. A bonus that has come from providing studio lunches is the growing number of photographers and models who ask Food Squad to cater their private dinner parties.

"Models just want to think they eat heathfully and normally," said Alan Mindel, vice president of the Click Agency. "The market wants healthy looking models and that's why the girls request a healthy studio lunch and say that's their normal diet. The truth is they would just as soon have a piece of pizza any day."

Monique VonHeel, a Dutch model with Click joked that she ate "chocolate and water". She then admitted that "a healthy diet leaves room for sweets once in a while."

"Everyone likes junk food because it makes you full right away and the high intake of sugar gives you a drug-like high," said Bernard Le Roy, a 27-year-old chef from the south of France who began catering studio lunches in New York just over a year ago. "When I do a studio job, the food is light, there's a difference from other catered lunches because some models are macrobiotic. I try to always have fruit since they're so conscious of diet. If I were to do a lunch for a commercial or television production involving both dieting actors and a union crew of brawny fellows, the menu would have to diversify of course. But healthy doesn't mean not filling. The added items would be a little more solid, including more starch and meat, with salads, soup and vegatables. Something for everyone.

"I am not forcing a trend on people. Some models prefer to bring their own lunches to the studio and it is usually something healthy and light. The way we think about food is changing."

"If all models want a different thing, they can go to the deli," says Le Roy who describes the people found on a fashion shoot as "a sophisticated crowd who like variety" and cooks accordingly. He provides a starch, a vegetable, a sweet (to satisfy cravings), meat, fruit, fresh bread. He avoids chemicals and provides natural beverages: Perrier, Evian and apple juice.

Last month, lunch during a two-day studio shoot that Le Roy catered included a spinach salad with tofu, mushrooms and radishes; the main courses were cold tortellini with asparagus, tomato and broccoli in a sesame sauce; and a hot seafood dish of sea scallops, shrimp and clams with broccoli and leeks. There was cheese, hard and soft; dark bread, fruit; split pea soup with ham; and a lemon tart for dessert.

Much to the chagrin of the photographer, Elisabeth Novick, there was no chocolate. "I know," comiserated Katharina Preser, a German model and Grace Kelly look-alike, "don't you love hot fudge sundaes?"

It seems to be a myth that models do not talk or think about food. These models found Le Roy's lunch to be quite good and had plenty to say about their favorite pastime.

"Soup, salad, fruit, cheese and bread are standard fare for a shoot," said New York model David Belafonte, piling a big plate of food. He was just back to solid food after a bad case of food poisoning but claims he has a fast metabolism and eats what he wants. To keep in shape he trains with free weights.

Peter Bock, a ski buff who looks like an instructor, claims his weakness is breads and muffins, especially when they are freshly baked as were those prepared by LeRoy.

Caroline Ellen, a model with Click, didn't mind putting her lunch plate aside while her hair was re-styled. "I like to eat slowly, I'd rather leave it until later than eat quickly. I eat a little at a time, all day long."

Shari Headley, a pro at 18, disagrees. "I eat like a pig. I hate when people eat celery sticks. Watch what you eat and exercise. I hate to exercise but I do and I just lost 15 pounds. Now I eat once a day," she said cutting a slice of lemon tart, "so this is it for today."

What's the worst eating disaster for a model? "Eating a meal that's not very good because you're starved," said Preser, "what a waste of calories if you don't enjoy the food." Shari hates to decide what to eat, "at the studio, I don't have to decide. It's already planned out."

"In Paris, they serve only sandwiches in the studio and you can blow up like a balloon if you're not careful," advised Preser as she spread butter on a piece of dark bread. Ellen agreed, adding, "I always bring some fruit along when I work in Europe."

"The first thing I look at on a menu is the dessert," said Preser, "then I look at what I can eat. I think about food and eating a lot." Her philosophy is "Watch what you eat but don't starve yourself."

By the end of lunch, there was barely a scrap of food left. All of the bread and pie and most of the cheese were gone.