So many diseases have been tied to the consumption of so many foods that some people seem afraid to eat. Geri Harrington has written a book, "Real Food, Fake Food and Everything in Between" (Macmillan, 1987, $24.95) to help them cope. The problem, however, she says, was to present the current food situation in a positive way so people wouldn't throw up their hands in despair.

"It is increasingly possible to eat better than we used to. We are getting foods that are leaner, with less fat and less salt. It shows that there is an effort on the part of the manufacturer to fill the needs the consumer is expressing," she says.

Many baby-food manufacturers are now refusing to use apples sprayed with the pesticide daminozide because they found mothers would not buy them.

And while consumers reject irradiated food for many of the wrong reasons, she says, the fact that many food processors are now refusing to use irradiated food is encouraging.

"The food people are responding to the consumer who is getting educated," says Harrington. "There is a lot of good food out there and there will be more as the consumer reaches for the better foods."

She says the only reason for processed food is that it is more profitable -- there's "more to be made from a box of instant potatoes than from a bag of real potatoes."

Harrington, who has been researching the quality of food for 20 years, is also an organic gardener, contract writer for the National Institutes of Health and author of 12 books. She wrote her latest book to warn consumers about the health hazards of many foods and to encourage them to insist on safer products.

"One night I had a nightmare that I was caught in a supermarket in a section with no food on the shelves. Then I realized that there are sections that are truly like that, with instant potatoes, imitation crab. It wasn't a nightmare, it is the way things are."

The 349-page book acts as a consumer's guide to supermarkets -- it shows what to avoid, what to look for and how to complain effectively.

One way, for consumers to protect themselves, she says, is to read labels and fight for good labeling. "The government is not as strong in this department as it might be." For example, she says, companies should not be allowed to advertise crude fiber on the boxes as if it were beneficial.

Crude fiber has no relation to dietary fiber -- in fact, it consists usually of wood pulp. "They shouldn't expect the consumer to know the difference," she says.

So buy the package that is more informative. And ask yourself why some products have so much added vitamins. "You have to wonder what they took out that they have to add it all."

The key to safe eating, according to Harrington, is to eat in moderation and with great variety. "Spread yourself out. If you really do that you're not going to eat too badly."

While "Real Food, Fake Food and Everything in Between" does not contain recipes, the following meal does follow in the spirit of the book:

Express Lane List: fish stock, pearl onions, peas, romaine lettuce, arrowroot, sole, orange, almond oil

SAUTEED DOVER SOLE WITH PEARL ONIONS, JUNE PEAS AND ROMAINE (4 servings)

1 cup fish stock reduced to 1/2 cup

1/4 pound peeled pearl onions

3/4 pound fresh June peas

1/4 pound romaine lettuce, cut into 1/4-inch strips

1 teaspoon arrowroot

4 soles or flounder, each weighing 10 ounces

1 navel orange

Freshly ground pepper

1 tablespoon almond oil

Bring reduced stock to a boil. Add onions and cook for 5 minutes. Add peas and lettuce and cook 1 minute longer. Mix the arrowroot with a little liquid to dissolve, then stir it into the vegetables. Cook for about 30 seconds to thicken. Set the vegetables aside and keep warm.

If you are using the whole fish, cut down until you reach the bones in the middle. Then cut along the center membrane the full length of the fish. Turn the fish and cut it the same way on the other side.

This will make it easier to bone after the fish is cooked. In the same way, if you are using fillets, separate each into 2 pieces by cutting along the center membrane.

Using a fine hand grater, grate orange rind onto one side of each fish or fillet. Grind pepper on top. Turn the fish and add more rind and pepper to the other side.

Heat the almond oil in a 10-inch nonstick skillet (or use 2 smaller skillets) over high heat. (The fish should fit in a single layer.) Halve the orange and squeeze the juice of one half over the fish. Put the fish in the hot pan and cook until browned on the bottom.

With a long spatula, carefully turn ech piece and cook onthe other side until done. Fillets should take about 4 minutes altogether, the whole fish with bones, 10 to 12 minutes.

Serve with the vegetables and a squeeze of orange juice.

From: "The Four Seasons Spa Cuisine," by Seppi Renggli (Simon and Schuster, 1986)