EVEN THE healthiest and most well-intentioned people do not, in fact, eat very well according to articles that have appeared on these pages.

That is why this contribution from Emily Guard of Laurel, Md., is of interest. Guard recently volunteered to keep a diary of her family's food intake for a week.

"I am the mother of three boys, ages 8, 4 and 6 months," she wrote, "trying to foster good eating habits in children while shopping economically and re responsibly in the face of the 'world food crisis.' I don't think these goals are incompatible, but it is a challenge. . . .

"We all have our weaknesses: My husband is a member of the 'steak, potatoes and Sara Lee school,' yet he takes his lunch to work most days, has broadened his range over the years and does fairly well. He still raids the vending machines. The children and I have our share of junk food, too, and we have hot dog and McDonalds nights.

We don't take vitamins. Nor are we vegetarians or 'health food nuts.' I know it is impossible to please everyone all the time as well as serve a variety of foods -- but I think it is worth the effort."

Guard's interest in nutrition began while she was pregnant with her first child. She delved into the popular nutritional beliefs of the era as reflected in countless books and magazines. She had lengthy discussions with friends who, she says "do as well as or better" than she does, and on occasion has had the nerve to challenge her pediatrician's counseling. From all these sources she took the advice she tended to believe and abandoned the rest Among her impressions:

Even the professionals don't know exactly what we need to eat for good health, so eating a variety of foods every day is better insurance than taking vitamins.

Homemade foods are more nutritious than convenience foods, and probably contain less harmful substances.

If children are exposed to good foods, they are more likely to continue to eat them later in life. Getting kids to eat vegetables, for example, is difficult, but if they try them occasionally, that's doing pretty well.

Since the world's resources are finite, it is important to be a conscientious consumer. To eat "as low on the food chain as possible," she tries to use alternate sources of protein as substitutes for meat.

It is important that male children learn to care for their own needs. Therefore, her oldest son, Glenn, has begun to prepare dinner for his family one night a week.

Everybody deserves some treats. But if kids are going to eat them, they should be nutritious ones. Guard, who does most of her own baking, adds nuts, raisins, whole grains, sunflower seeds and fruit to products like gingerbread, fruit breads and cookies. She also prefers to reduce the amount of sugar these recipes require.

It is easier to agree with these principles than practice them. Guard pointed out. There is some question, for example, whether choosing more nutritious foods is actually cheaper than using similar, less nutritious alternatives. "i am not particularly interested in economizing on food," said the thin, brown-haired woman. "If I wanted to feed my family in the cheapest way possible, I could shop much more efficiently than I do. But then we would be eating white bread (rather than those with whole grains), American cheese and Hi-C. I certainly wouldn't be buying nuts."

The family eats meat about once a day, usually for dinner. Breakfasts for Emily Guard and the children include eggs, Cherrios, oatmeal, coffee, toast or orange juice. Her husband, Barry, usually skips breakfast, though on weekends he may join his family for pancakes. After recently returning from a business trip to London, he indulged in about a week of heavy English breakfasts. "that stopped pretty soon," Guard explained. "He likes his sleep."

Lunches for her and the kids include cheese, tuna, leftover meat or peanut butter sandwiches or salads. Now that school is in session, Glenn usually has his lunch at school for 55 cents a day plus a dime for an extra carton of milk. Snacks throughout the day are fruit, vegetable sticks, ice cream, milk, fruit juice, tea and homemade baked goods.

Barry Guard, an electrical engineer, takes clients to lunch about once a week. Although his company picks up the tab he estimates the value of these meals to average $5 a week. He may spend another $5 on snacks such as cola, coffee, candy and peanuts.

Each family member's diet fulfilled the requirements of the Department of Agriculture's basic four food groups, and was not excessively high in saturated fats, salt or sugar. The Guards are all in good health and are not overweight. Like most Americans, their diets are somewhat lacking in a variety of foods from those vegetables that are bright orange or deep yellow -- except for carrots, which Guard serves two or three times a week. Her selections of a dark green and leafy vegetables included cabbage, spinach and broccoli.

Guard uses an ancient, time-tested method of budgeting. At the beginning of the week she places $53 in a special compartment in her wallet. When it's gone, it's gone.

The main expenditure is for a weekly shopping trip. To prepare, she scans the newspaper advertisements, makes a shopping list and practices all the other traditional economies.

In addition, she is among many area families who have turned to wholesale sources of food to help them beat inflation. The family is a long-standing member of the Pheasant Run Produce Cooperative, a group of 12, each of whom pools $6 a week to finance a trip to Kossow's, a produce wholesaler in Washington. The families take turns making the trip. They buy some staples regularly; the buyers then use their discretion to make other purchases based on availability and price. Then the goods are divided equally among participating families. More recently Guard joined a group of women who plan to make regular trips to the Potomac Butter and Egg Company for cheeses. She figures these efforts save 40 percent of supermarket prices on produce and from 30 to 50 percent on cheese.

During a recent week she spent $33.23 at the supermarket, plus $8.11 on eggs and produce at the co-op. Another $8.97 worth of food previously purchased was used to bring the week's food bill to $50.40.

According to the Department of Agriculture's national averages for cost of food at home, a family like the Guards might spend between $46.75 for a low-cost food plan, to $89.70 for a liberal one, providing that all meals are eaten at home. According to the Bureau of Labor Statistics, food prices in Washington are 2 percent higher than the rest of the nation.

Food eaten away adds to the food bill significantly. The Guards dine out alone about once a month, spending between $15 and $20. They also take the boys out once amonth, visiting modest restaurants where the bill averages between $7 and $15. Their total food bill would look something like this: $23.86 -- main shopping trip to supermarket $6.08 -- extra trip for (whole) milk $8.11 -- produce and eggs $8.97 -- previously purchased food choices from pantry etc. $3.39 -- extra milk $5 -- Barry Guard's lunches (average) $5 -- Barry Guard's snacks (average) $7 -- restaurant meals (average) $3.25 -- Glenn's school lunches $71 -- Total THE GUARD'S DINNER MENUS

Monday: Raw vegetables with dip, ham, mashed potatos, cabbage, biscuits, milk, chocolate ice cream cones, coffee

Tuesday: Tacos with meat, onions, tomatoes, lettuce and grated cheese, extra tomatoes, milk.

Wednesday: Meatload, baked potatoes, spinach, sliced tomatoes, milk, peach pie.

Thursday: Salmon cakes, mashed potatoes, broccoli, cole slaw, sliced tomatoes, milk.

Friday: Pepper steak, oriental brown rice salad with Romaine, milk.

Saturday: Bacon, lettuce and tomatoes on toast, three-bean salad, deviled eggs, milk.

Sunday: Baked chicken, baked potatoes, broccoli, tomatoes/cucumber/green pepper salad. WHEAT GERM GINGERBREAD (9 servings) 2 cups unsifted all purpose flour 3/4 teaspoon salt 1 teaspoon baking soda 1 1/2 teaspoons cinnamon 1 teaspoon ginger 1/4 teaspoon cloves 1/4 cup sugar 1/2 cup wheat germ 1 cup buttermilk or sour milk 3/4 cup molasses 1/3 cup all purpose vegetable oil or margarine 2 eggs, beaten

Preheat oven to 350 degrees. Generously grease a 9- by 9- by 2-inch baking pan.

Sift together flour, salt, soda, spices, sugar and wheat germ. In a separate bowl combine milk, molasses, oil or margarine and beaten eggs. The margarine need not be melted. Beat until smooth.

Combine liquids, with dry ingredients and pour into pan. Bake for 45 to 50 minutes or until a toothpick inserted in the center comes out clean. If desired, serve hot with applesauce.