"I keep more food in the frig than my father does. He doesn't know what to do with it ."

Keith Vandivort

Like Francois Truffaut's Antoine Doinel, our subject is growing older and assuming a place in society. The first snapshots in this series were of a high school student, then a composite of those who leave the family dining table for college. This week: a senior in law school who watches his weight and food choices more carefully than he did a few years ago.

Keith Vandivort is 26. A bachelor who lives alone in an Arlington apartment, he does his own grocery shopping and cooking. That he can cook, and likes to cook, sets him apart somewhat from his contemporaries, he feels. But like most of them, he finds time is a major factor in deciding what, when and where to eat. Study at Georgetown University plus a part-time job at a law firm keep him away from the apartment as much as 12 hours a day. "What a few exceptions, people I know at law school do not eat a balanced diet," Vandivort said last week. "I think they are more conscious of what they are eating, but they eat when they are hungry and settle for whatever is readily available. They turn to faddish foods, bean sprouts and yogurt. They do something-jogging, racquetball or exercises. They are paying more attention to their bodies, but they are not skilled as cooks and many of them don't necessarily try to make food at home. Several of my friends are somewhat astonished that I will cook a complete meal when I ask them over."

In the past year, with money coming in from his part-time job, he bought a set of pots and pans ("like the ones I knew at home when I was a kid") and some tableware, and occasionally will indulge himself at a full-service restaurant such as The big Cheese or Nathan's Jogging has replaced intramural sports as his chief form of exercise. His sense of nutrition is instinctive, inspinctive, inspired by the eating philosophy of his mother ("she likes salads, doesn't care for red meat much and eats lots of yogurt") and a sense that certain foods are bad for him.

On balance, although he eats irregularly, Vandivort's instincts appear to be good. He eats more fruits and vegetables than do most of his contemporaries. His intake of red meat and carbohydrates is moderate. Few of the foods he eats are highly processed or riddled with additives. He weighs himself frequently and moderates his diet if the scales show he is gaining.

"I couldn't tell you," he replied when asked about the Basic Four food groups. "I haven't set out to read about nutrition because I don't think I have to. I know some things put weight on and screw up my complexion: fried foods, anything greasy, chocolate, cake."

As he tells it, two events shaped his approach to eating. At 13, his parents were divorced. He, his brother and sister, lived with their father in Toledo, Ohio. "Dad couldn't do anything in the kitchen," Vandivort recalled. We kids did the cooking. I learned to cook because I had to. But in high school sometimes I never sat down. I'd run in and grab something, and leave the dishes. I ate lots of pizza, hamburgers and french fries."

The second was a decision after his first year at Northwestern University to lose weight. "I had been heavy through high school, but I had hit a high of 170 pounds. I didn't feel good and I didn't look good. I concentrated on salads and cut out candy and junk. By the end of my sophomore year I had my weight down to 140."

He also gave up smoking, but that resolve didn't last.

During his first three years at Northwestern he ate on campus. Then came a year in an apartment, a year of law school in 1976. "I was scraping for money, so I ate so much Chef Boyardee I'll never touch it again." Last year, in a house with three others, he was one of two cooks "primarily by default."

"I can gain five pounds over a weekend," he said. "I hold back on bread and starches and try to limit butter, margarine and fried foods. I don't follow a formal diet. My body will tell me. If I haven't had a glass of milk for a day, I get a craving for one. It's the same with sugar, though, and I have a weakness for ice cream and can get a real bad craving for chocolate."

Currently, at 5 foot 7 3/4 inches, he is dropping toward 145 pounds after a winter of physical inactivity during which his weight went over 150.

As the record he kept over a two-week period shows (see box), he ate a light breakfast regularly and tended to skimp at mid-day. A mid-afternoon snack may be cheese and crackers at the law office or merely M&Ms at school. Salad is a staple in the evening. Though he does not consider himself a vegetarian, he does not "think first of meat when planning a meal."

Vandivort shops once a week at a supermarket, usually Thursday night or on Friday, a day when he neither has classes nor works. He avoids shoping at peak hours, "when the selection of meats and vegetables have been picked over," and is a sucker for items on sale, from ice cream to ham. His weekly bill is $20 to $25, though he eats lunch and an occasional dinner in town and some weeks he will return for a steak, a frozen entree or a pizza.

He buy mostly fresh fruits and vegetables, although he will buy frozen corn and peas. His interest in English muffins has dropped off and his cereal taste has swung toward Raisin Bran of late. He buys frozen pie shells to use for quiche, and makes the filling himself using mushrooms or onions as the central ingredient. If he keeps to his plan, he will make a quiche or bake a ham or pork roast on Friday, then eat the leftovers through the weekend. He keeps a large container of plain yogurt on hand and mixes either fresh fruit or jam into it. This may be eaten in place of cereal for breakfast.

Vandivort does not make sauces or do complex food preparations. He has had a wok for a year and a half, but hasn't used it lately and never did try to do Chinese recipes in it. Instead he stir-fried vegetables. His only cook-book is "Joy of Cooking," but he tends to cook without referring to recipes. He prefers making roasts or casserole dishes that cook without attention once they are prepared. He uses leftover bones plus vegetables and water to create soups. Sometimes he bakes cookies or makes brownies by using mixes. He relies on bottled or "instant" salad dressings.

"I've been eating a lot of salads the last few months," he said. "I generally make them pretty large and will eat one while I watch the news on TV or read. I use lettuce and onions and carrots and celery.Lately I've been using bean sprouts and spinach. I'll add croutons and sometimes grate cheese on it."

He drinks milk and Scotch (separately) year round, prefers wine in the winter and beer in the summer. He buys pre-ground coffee, but uses a filter to make it.

Vandivort likes to invite two or three friends for meal on Friday or Saturday evening, but with the approach of final exams he has not done so recently.

His refrigerator is ready for any emergency, however. Here is a list of its contents last week.

In the freezer: 2 or 3 frozen Stouffer's dinners ("the only kind I buy") and one of their French bread pizzas, a package of chicken parts, 1 or 2 pounds of hamburger, a package of half-chocolate and half-butter almond ice cream plus another coffee-flavored. ("Breyer has been on sale," he explained.)

In the refrigerator compartment: orange juice, milk, butter, condiments (mustard, catsup, relish and pickles), yogurt, cottage, Swiss and cheedar cheeses, broccoli, iceburg lettuce, onions, tomatoes, bean sprouts, celery, carrots, spinach and three or four flavors of jam and jelly.

"I'm interested in food and I'm willing to spend a couple hours sometimes preparing a meal," Vandivort concluded. "I'm not an amateur chef. It could happen, but I'm not ready to spend the time.

"Most of my friends are still eating to exist. They probably would be willing to spend more money on food, but their time is limited and their focus is elsewhere. And some of them are just too insecure in the kitchen to try anything. I guess I was lucky." CAPTION: Picture, Keith Vandivort at home, by Joel Richardson-The Washington Post; Picture 2, no caption;; Chart, Day by Day