BY THE MIDDLE of this decade the cost of food was going up at the astounding rate of 20 percent a year. The climate was ripe for consumer advocates and the consumer movement came into its own. People were predicting "consumerism is here to stay."

Food additives were making headlines. Dr. Benjamin Feingold's theory that some children exhibit hyperactive behavior because of food additives created quite a stir.The safety of sodium nitrite had become an important consumer concern. Labels of all products cured with nitrite had to list the chemical's presence on the label. Two years before, the Food and Drug Administration had proposed removing nitrites from smoked fish.

FDA still hadn't banned Red No. 2 food coloring, but the National Foundation of the March of Dimes was warning about its hazards.

The agency also decided it couldn't ban all the impurities in food. It set tolerance levels for some of the toxic substances -- mercury, lead and aflatoxin. Dr. Sidney Wolfe, director of Ralph Nader's Health Research Group, called the decision "unconscionable."

The Federal Trade Commission, just beginning to respond to earlier complaints that it was not performing effectively, issued a proposal to regulate food advertising.

More and more people had come to the conclusion that convenience foods weren't necessarily convenient, cost a great deal of money and contained additives they didn't want to eat. Homemade convenience food recipes became among the most popular printed in this newspaper's food pages.

The Sugar Association was worried about sugar's bad press and put on a program at the annual Newspaper Food Editor's Conference entitled "Exploding Myths Associated with Sugar." Another sugar substitute, aspartame, surfaced . . . and then sank. Consumer activists forced FDA to reconsider its safety before it reached the market.

The national school lunch program was in such disrepute that children were leaving it at the rate of 500,000 a year. Nutritionists and food writers were offering brown-bag alternatives that included such daring innovations as brownies made with while wheat flour.

Whole wheat bread was making its way out of the health food stores and into the supermarkets. Bread, in general, was making a comeback: Vie de France led the way in Washington.

Brown rice and bulgur were moving beyond kitchens of health food faddists.

Quiche appeared to have peaked, but only among those who follow the latest high fashions in food. Gazpacho was being replaced by yogurt soup.

There was talk of a new breed of French chefs, some of whom were spending more time promoting a deceptively simple new French cooking, nouvelle cuisine, than preparing it. The dishes, which took many cues from French bourgeoise cooking and from the Oriental, featured barely cooked vegetables, meticulously cut into small pieces, sparse presentation that depended more on line than substance, and sauces thickened by reduction instead of flour.

"New" Chinese regional cooking was replacing the old. Szechuan was coming up fast on Cantonese in Washington, but in New York, Hunan appeared to be edging out Szechuan.

Crudites had replaced bacon-wrapped whatevers. Fresh herbs were no longer just a curiosity grown in 18th-century gardens. Homemade pasta had become chic.

Fresh pasta, not necessarily homemade, is even more chic in 1979, partly because fresh is in, partly because people are beginning to understand that carbohydrates don't necessarily mean fat, and partly because sirloin steaks cost $3.29 a pound, boneless chuck roasts $1.89, a ground beef $1.59.

The increases in food prices in 1969 and 1974 were only a prelude to 1979's food inflation. The enormous rise in the price of beef has been matched this time by price increases in almost all food.Cantaloupes are 69 cents each in season, a head of cauliflower is $1.59 and oranges are double their 1969 price.

The $1 which bought 80 ounces of bread 10 years ago and 48 ounces five years later will now buy only 44 ounces, and the 69-cent coffee costs $2.89 today.

Food prices, which increased at a slower pace between 1975 and 1977, are once again climbing at the double-digit rate, with no end in sight. And once again the finger is being pointed at the food industry's middleman for excess profits.

If anything, the food industry is more concentrated than it was 10 or even five years ago. Locally, Safeway and Giant have increased their share of the market to 70 percent, up 12 percent in five years.

As prices rise, many economies that were practiced in 1974 have reappeared. The public, which wasn't ready for lean beef five year ago, is buying it in 1979 to save a little money and a lot of fat. With the concern that the way to a man's heart attack may be 16-ounce steaks and quarter-pound hamburgers, chicken and fish also are enjoying greater popularity, as is vegetarianism.

Though fish has just about priced itself off economy menus, 29-cent-a-pound chickens of 10 years ago can be had for 49 cents a pound on sale today. Though turkeys have doubled in cost they are still among the more reasonable meats. At the same time, the relatively reasonable price of pork, no less fatty than beef, has made it extremely popular. The 55-cent-a-pound pork loin roast of 1969 costs $1.29 a pound now (20 cents a pound less on sale.)

Some of this year's inflation-fighting tools were unknown five years ago. "Generics," or brandless dry goods and canned foods, are doing very well. These are usually of lower quality than store or national brands and much less expensive. The canned foods are of equal nutritional value to their more expensive counterparts.

No-frills or box stores, warehouse stores and co-ops, where the amenities are limited and so is the assortment, are making inroads into the traditional supermarket business because they sell products for much less money. It may pay to shop around -- but who can afford the gas!

Refunding has become even more popular than it was five years ago.

The spotlight on food safety has begun to shift to concerns about the relationship between diet and health, though only a minority of the population has actually changed its eating habits. "Dietary Goals for the United States," a 1977 report by the McGovern Senate Nutrition Committee, has become a blueprint for healthy eating. The goals suggest an increase in the consumption of fruits, vegetables and whole grains and a reduction in fat, cholesterol, sugar and salt intake. This is a dramatic shift from USDA's advice of 10 years ago that "all food is good food."

These new concerns have turned a small market for whole grain breads into significant competitors for the white bread market and spawned a "new" name -- wheat bread.

Sugar continues to decline in favor, prompting the Sugar Association to put out a new booklet entitled "Why Sugar" -- same song, new words.

Sugar-coated cereals continue to enjoy a bad press, but new ones are marketed every year. One company, however, is test-marketing a sugar-coated cereal with less sugar, and cereal companies are spending some of their advertising dollars on products with bran, a natural fiber. Even old-fashioned oatmeal has an advertising budget today.

The popularity of polyunsaturated fats and cholesterol-free foods may have peaked as low-salt, low-fat foods have begun their ascent. It may even be time for the caffeine-free cola that bombed 10 years ago. Bottled waters, unknown just two years ago to all but European travelers, are taking over soft drink shelf space.

The school lunch program, which is no longer losing participants, is making efforts to improve the nutritional quality as well as the taste of the meals served. USDA has made attempts, however feeble, to regulate the nutritional value of food that can be sold in school vending machines. More people are reading labels because they are concerned not only about additives but about sugar, salt and fat content. But instead of labels that are easier to understand, they've become more complex.

New proposals to simplify nutrition labeling and to include information about sodium, sugar, fat and cholesterol have just been announced. Unit pricing is here to stay. Some fresh foods are open-dated.

Fears about additives have brought on a rash of so-called "natural" foods. Though the term is impossible to define, manufacturers are plastering "natural" on dozens of not-so-natural products: potato chips, fruit-flavored drinks and ice cream that contains artificial color.

The halcyon days of the consumer movement are gone, though some aspects of it, like those who lobby for federal feeding programs, continue to flourish. But several of the movement's leaders joined the Carter administration in the belief they could work more effectively within the system. Now they are finding that sophisticated industry lobbies are able to thwart their efforts to regulate by successfully seeking congressional action.

Saccharin is still ubiquitous, thanks to a congressionally-mandated moratorium on a ban. Sodium nitrite is still in smoked fish as well as cured meats. Health Research Group has one again asked the government to ban it.

Consumers may have a voice in some government deliberations, but they don't speak as loudly or effectively as industry. FTC has yet to produce final regulations on its 1974 proposal to govern food advertising and it has had its wings clipped so many times this year by Congress it can barely walk, let alone fly.

Red No. 2 food coloring is gone and so is Red No. 4, but eight other artificial colors are still in the food supply.And some convenience foods are selling better every year as more and more women join the work force. But instead of creating new fake foods to mimic real ones, the food industry is concentrating on foods that working people can heat and serve when they get home.

Women in the work force have spawned another phenomenon -- men in the kitchen. One of the most popular features run by this Food section this year was a column entitled "The Husand's Cookbook."

The conservative mood in this country is reflected in what we eat in a curious way. There is a trend toward moderation in the diet and a return to old-fashioned whole foods. At the sametime convenience foods are gaining in popularity, so are the basics. Fruits and vegetables that were available only in speciality markets five years ago, or in some cases not available at all, are found in many supermarkets.

Americans have become far more curious about quality food than they were 10 years ago and far more demanding. In quest of fresh, farmers' markets and roadside stands are enjoying an enormous resurgence, and hand-crafts foods, like the fresh pasta, are selling better and better each year . . . at a price.

But we have yet to solve the problem of overnutrition. We are eating fewer calories than we did in 1969, but we are even more overweight than we were then.

We have, however, been able to dramatically reduce malnutrition through government feeding programs.

The phenomenon of this decade has been the inexorable march upward of food prices. In the past, price increases have always been followed by a price drop. The '80s holds out no hope of relief.

Food prices, nutrition and environmental pollutants -- these are the challenges of the next decade.

At the same time, Americans' insatiable appetite for the new will make itself felt in an ever-expanding interest in experimentation with new ways of cooking and a search for new foods.

Just last week I found taco-flavoredpita bread.

Can chocolate-covered tofu popsicles be far behind?