WHEN THE U.S. SENATE voted recently to shut down its Select Committee on Nutrition and Human Needs, more than a few senators were hard pressed to recall why the committee was created in the first place just eight years ago. For those of short memory, the nutrition committee emerged out of the public discovery that millions of Americans went to bed hungry at night or suffering from malnutrition, and that the country as a whole was nutritionally illiterate.

Out of that awakening and strong advocacy by the Senate nutrition committee and other groups has come some remarkable progress. The food stamp program now reaches a substantial number of the poor and near poor, and the free school lunch program is helping millions of poor children to get a better diet. Furthermore, thousands of people, poor and unpoor alike, have learned enough about nutrition to recognize that the typical America diet is not all it was cracked up to be. Too many Americans have been dying too young of nutritionally related degenerative diseases for us to smugly proclaim that we are the best-fed nation in the world.

The question now is whether the progress that has been made will continue, or will be lost as the trendy government and news media march off to discover new issues. Some of the portents are not good. The Senate nutrition committee has been given a one-year lease on life, but after that the citizen will have to depend on congressional agriculture committees, which historically have been preoccupied with the problems of producers and processors, not those of consumers. Welfare reformers propose to eliminate the food stamp program as part of the process of "rationalizing" the welfare system. One can only hope that Congress and the Carter Administration won't eliminate the country's commitment to give every American an adequate diet, as part of the process of dealing with welfare.

If there is a bright spot in this picture, it is the emergence of a genuine food movements in this country. In the early days this movement was carictured as a counterculture phenomenon in which mung beans in a natural food store. This description may give comfort to smug executives in agribusiness but it does not accurately convey the actions of many Americans in all walks of life who are expressing concern over how their food is grown, processed, distributed and cooked. These Americans are now scrutinizing the small print on food labels in supermarkets, forming thousands of co-op buying clubs to get cheaper and fresher produce, and trying to eat a more nutritious diet.

The movement has produced some angry books, lambasting the food industry for its pursuit of profits at the expense of the small farmer and the consumer. Now the movement seems to have reached full maturity with the publication of this "how-to" book from the Rodale Press. (Rodale's two magazines, "Prevention," and "Organic Gardening and Farming" have a combined circulation of almost three million, which is some indication of growing public interest in better food.)

This book spends little time railing against the abuses of the food industry. Instead, it cooly and encylopedically details literally hundreds of ways to improve your diet, from growing food to following recipes. Ray Wolf, the book's editor, has pulled together valuable information from several dozen sources on the subject of food. The average consumer cannot fail to learn something from this book, and it would be a valuable nutrition textbook at either the high school or college level.

The information on gardening ranges from basic facts about how to plan a garden to detailed advice on "succession planting." For example, lettuce of late cabbage can be planted after peas are harvested and will thrive on the nitrogen that the pass have added to the soil.

Grocery shoppers are advised as a general rule for a better diet to start spending twice as much money as before in the produce section, half as much in the meat section, and not one cent in the canned good, deli or desert sections. Supermarkets are given good marks for economical purchase of dairy products and fruit juices, but specialty stores are recommended for purchase of produce and whole grains.

And if you want to pick your own fruit and vegetables right out of the farmer's field, you find you can simply call your county extension service agent (including oned in Gaithersburg, Fairfax, and the District) to get a list of several hundred farms in Maryland and Virginia from which you can "pick you own." For the less athletic, the agents have another list of farmers' markets.

If you want to join a food purchasing co-op or start one of your own, the book tells you whom to contact and how to proceed.

The nutrition section of the book begins with the warning that you can serve something from each of the four basic food groups and still have a horrible diet. If you don't want to lose most of the vitamins and minerals in vegetables, you are advised to retain the outer leaves, quick rinse rather than soak for cleaning, cook with a minimum of water and without salt.

Most American diets, the book contends, contain too much fat and protein, and these from the wrong sources, and not enough carbohydrates, and those currently eaten from the wrong sources - namely, refined grains. Interesting meals are described in which a vegetable-grain main dish provides protein, a vegetable casserole and salad provide carbohydrates, and salad dressing provides fat. Most Americans are unaware of how much sugar and fat are in their diets, because these ingredients are disguised in processes good. Most brands of peanut butter, for example, are laden with sugar. Another section of the book provides numerous recipes for tunning leftovers into interesting meals the next day.

The book provides graphic nutritional information. For example, did you know that 100 grams of turkey (three medium-size slices) contains more protein than a half-pound lean porterhouse steak? ANd the turkey contains only 200 calories while the steak has 800.

If you want to know how to store and best preserve your home-grown or store-bought food, the book tells you everything from how to make a root cellar to how to can, freeze, dry, brine, or smoke foods.

For people who want to eat better, and gain some measure of control over one important aspect of their lives, this is a rewarding book.