In the middle of an otherwise forgettable college social science class, the teacher noted that the feed grain needed to produce one 8-ounce steak could provide a grain meal for 40 to 50 people.

A couple of nights later, as I crunched on a Kentucky Fried drumstick, I started thinking that maybe one could center dietary habits on something other than dead animals.

"So maybe I'll become a vegetarian," I thought.

That was 10 years ago this month. I've hardly eaten meat since and haven't missed it a bit.

During the last 10 years, my fellow Americans have boycotted meat because of high prices, killed themselves drinking liquid protein to lose weight, blown fortunes on Perrier water, Cuisinarts, outrageously expensive health-food novelties, weeks of elegant starvation at La Costa, enough diet books to bury Cleveland -- and have generally persisted in regarding vegetarians as crackpots.

When I first decided to stop eating meat, the word "vegetarian" conjured up images of bony Bolsheviks trafficking subversive pamphlets in the back rooms of health-food stores. At that time it often was regarded as a really righteous trip for your karma to keel over from trying to live on nothing but brown rice.

Now, mercifully for those of us who have spent the last decade mumbling and blushing as we confessed our peculiar lifestyle, respectable organizations such as congressional committees and the National Institute of Science agree that cutting meat consumption down -- or even out -- not only doesn't kill people, but benefits their health.

I often have wished for a more positive-sounding description of my life style. "Lacto-ovo-vegetarian" sounds more like a fungus preying on pregnant women than someone who lives on a combination of fruits, vegetables and grains supplemented by occasional use of dairy products.

But no matter what the descriptive term, the life style itself in a way challenges our culture's assumptions about the necessity and desirability of meat. What's more American than steak and potatoes, hamburgers and fries, hot dogs at the ball game, bacon and eggs for breakfast?

And what did all those pioneers go out there and win the West for, anyway -- the right of future generations to enjoy alfalfa sprout sandwiches?

Pass on the meat entree at a restaurant or dinner party, answer the inevitable question why, then listen to the equally inevitable, "If you don't eat meat, what DO you eat?" or even better, "Oh, my God, if I didn't eat meat, I'd suffer from migraines-lose my virility-faintdie."

Our Anglo-Saxon heritage and the firmly entrenched and efficiently advertised meat industry have helped establish that somewhat misguided attitude. Human beings do need protein to survive; 30 grams a day suffice. The Food and Nutrition Board National Research Council recommends 55 grams for women and 65 for men.

Studies published by the National Academy of Sciences have shown that "vegans" (people who subsist on plant food only) average 111 percent, and that meat-eaters consume nearly twice the protein they need, 171 percent (women) and 192 percent (men).

Some scientists call this overnutrition. With current meat prices ("Hamburger prices in '79 to reach '78 sirloin levels" read a headline recently), budget experts might call it overspending. But because of the high levels of cholesterol and saturated fat in the meatloaded American diet, many scientists have begun to call it downright dangerous.

In the words of the Journal of the American Medical Assn., on June 3, 1961: "A vegetarian diet can prevent 90 per cent of our thrombo-embolic disease and 97 per cent of our coronary occlusions."

According to Science Magazine, February 1974: "Populations on a high-meat, high-fat diet are more likely to develop colon cancer than individuals on vegetarian or similar low-meat diets."

In 1977, the Senate Select Committee on Nutrition and Human Needs issued a report entitled "Dietary Goals for the United States." The report linked the average American diet to "6 of the 10 leading causes of death" in this country (heart disease, cancer, cerebrovascular disease, diabetes, arteriosclerosis and cirrhosis of the liver) and urged drastic reductions in our consumption of animal fats, cholesterol, table sugar and salt, balanced by an increased use of fruits, vegetables and whole grains.

And a special note for women. Several studies have correlated the incidence of breast cancer to high meat and fat consumption. One survey found that Japanese women's breast-cancer rate increased when they moved to America and changed their native low-meat, low-fat diet to American eating habits.

Fortunately, as all this evidence against meat-eating has accumulated, so have the available alternatives. The salad bar and ethnic restaurant crazes have helped introduce us to the great variety of meals that don't contain meat. Mushroom pizza, Greek spinach and cheese pie, vegetable fried rice and egg foo yung, meatless quiche, guacamole and tortillas, cheese fondu, German apple pancakes, dozens of unpronounceable Indian dishes -- you see what I mean about the American cultural assumption of the necessity of meat.

As to the moral issues, many world food distribution experts simply take it for granted that unless somebody works a big miracle in the next couple of decades, the inhabitants of this planet will have to stop feeding grain, peanuts, soybeans and fishmeal to livestock, and start feeding them to humans.

We can no longer afford 16 pounds of feed to produce 1 pound of edible beef, they will tell you. Of course, this assumes the development of a global food policy -- which many world food-distribution experts contend will have to happen, too.

And some vegetarians, with little prompting, will describe for you in graphic detail the slaughtering process. We don't like to think about cows, pigs and chickens squealing, squirming, bleeding and dying, and we don't like to think about ourselves gnawing on the muscles of their corpses.

Of course, no one in this country who plays dice, wears makeup, drinks beer or wine, watches movies, listens to string music, plays tennis, uses a baseball mitt, or owns a down jacket or sleeping bag can afford to get too sanctimonious about exploiting animals, since all those activities involve the byproducts of slaughter.

Unfortunately, a meatless diet does not prevent the onset of obnoxious evangelistic tendencies in some vegetarians, nor the overwhelming desire in some to perpetrate acts of senseless violence upon them.

For some of us, for whatever health, economic or humanitarian reasons, "The less, the better" works as a sensible guide. I'm just grateful that as more and more Americans recognize the wisdom of eating less and less meat, vegetarians are no longer dismissed as (you'll pardon the expression) nuts.