March is National Nutrition Month, and to spread the message members of the American Dietetic Association, the country's largest group of nutrition professionals, will be sponsoring health fairs, educational events and promotional activities.

Two themes will dominate, according to Gilead Leventhal, a registered dietitian and chairman of the public relations committee of the District Dietetic Association.

One, says Leventhal, is the idea that healthy food is not only good for you, but that it also tastes good. The other is self promotion by ADA dietitians, in large part because of the increase in what they call nutrition quackery. The association is concerned about the growing number of people with few or no credentials calling themselves "nutritionists."

Locally, National Nutrition Month activities include: Red Cross Fun Run Health Fair at the Post Office Pavillion March 10. Events will include a five killometer race, computer diet analysis and a puppet show. For more information call 727-5930. Ext. 50.

A series of supermarket shopping tours will be sponsored by the Mayor's Commission on Food, Nutrition and Health. The tours will help consumers identify low sodium, low cholesterol and diabetic products. They will be held every half hour from 9 a.m. to noon, Fridays in March at the Safeway in the Hechinger Mall, 15th and H Sts. NE. Call 398-6903 to reserve space for large groups.

Good nutrition reading lists will be available at Northern Virginia libraries all month. Nutrition message bookmarks are free to take home from the libraries as well.

"Osteoporosis and You," a program sponsored by the Fairfax County Department of Extension and Continuing Education, includes presentations of diagnosis, prevention and treatment of the disease; March 19 from 9:30 a.m. to 1 p.m., Tyson's Corner Shopping Mall, Town Hall Meeting Room. Call 691-3433.

The lobby of the Walter Reed Hospital features an exhibit on weight control, nutrition for athletes and nutrition myths, tomorrow through March 22. The medical center is located at 6825 16th St. NW. 545-6700.

Dietitians from Maryland, Virginia and the District will discuss the dietitian's role on Alexandria Cable TV. Mondays at 6 p.m. through March.

For a list of registered dietitians in this area, send a stamped, self-addressed envelope to: Consulting Nutritionists, 1848 Ingleside Terrace NW, Washington D.C. 20010.

To observe Nutrition Month at home, try this tofu chili recipe that Leventhal has contributed to the Express Lane. All you need at home is oil.

EXPRESS LANE LIST: onions, garlic, chili powder, cumin, canned tomatoes, kidney beans, tofu, brown or white rice. GILEAD LEVENTHAL'S TOFU CHILI (4 servings)

1 tablespoon oil

2 small onions, chopped

2 garlic cloves, chopped

1/2 pound soft tofu

1 1/2 teaspoons chili powder or more to taste

1 teaspoon cumin

28-ounce can crushed tomatoes

15-ounce can red kidney beans, rinsed and well drained

Brown or white rice, cooked

In 1 tablespoon oil, saute' onions and garlic until almost tender. Add soft tofu and spices. Add crushed tomatoes, beans and allow to cook for 20 minutes. Serve over cooked rice.