Ten years ago at the age of 32, Thomas J. Greshen of Baltimore began fighting his weight. He has had few victories.He now eats even more and exercises less. And his weight has increased steadily - from 250 pounds to 475 pounds.

In a real sense, Greshen's struggle against his weight problem has become a struggle for life. With each new pound, he increases the chance that he will be the victim of a disabling disease, social and economic discrimination, and an untimely death.

Yet Greshen continues to gorge himself with the calorie-rich foods he loves. He eats partly in out of tradition and habit and partly in response to compulsions that set off eating binges.

Over the years, Greshen said, he has lost touch with the true feeling of hunger. Eating is now his response to feelings of joy, sadness, anxiety, boredom, pride, fear and the smell and attractiveness of food.

"This thing has me scared," said Ghreshen, a worker at a Baltimore ice cream cone bakery who is the father of three. "If I keep gaining, I could lose my job. My family doesn't want to be seen with me in public because they say people laugh. And my doctor tells me that in 10 more years I could be an invalid - if I live that long."

Greshen's experiences sound extreme and even bizarre, but he is not alone in his bout with obesity. In a society that has made slim and slender its ideal, obesity has nevetheless become a public health problem of epidemic proportions.

According to the U.S. Public Health Service, more than 79 million Americans are affected to some extent by overweight and at least 1,109 persons are known to have died prematurely in 1975 from overnutrition.

In recent public hearings, the U.S. Senate Select Committee on Nutrition and Human Needs cited obesity as the nation's "number one malnutrition problem." The committee reported that fully 30 million Americans are obese - or 20 per cent overweight based on height, age and sex standards - and 15 million U.S. citizens are obese to a degree that limits optimal health and life expectancy.

While there is great dispute over the impact of obesity on health, many doctors believe that excessive weight can lead to a number of serious health disorders, including hypertension, diabetes, gall bladder and liver disease, osteoarthritis (from pressure of excess pounds on weight-bearing joints) and premature heart attack, the main killer of the obese.

Yet most Americans remain what some nutritionists call "weight control illiterates." They know little about the caloric content of what they eat or how much activity is required to burn off excess energy their bodies don't need.

In the case of obesity, ignorance translates easily into extra pounds and bulk. An average man who begins weighing 150 pounds and pursues an indiscriminate eating and activity pattern can at least double his weight in one 12-month period, according to the experts.

Much of the dramatic rise in the number of obese persons here is due to the life-style of increasing leisure and inactivity that more and more Americans have enjoyed since World War II.

Today Americans are spending more and more of their grocery budget on calorie-rich foods they often munch while sitting in front of a television set. Driving has replaced walking for short distances. And sports are enjoyed more often from the stands than from the playing field.

At the same time, according to Hofstra University sociologist Natalie Allon, American spend $10 billion each year on efforts to lose weight.

More than $15 million is spent on weight watching clubs and clinics; $220 million on health spas and reducing salons; $100 million in the exercise equipment market; $54 million on diet pills and $1 billion on diet foods, books and literature, she said.

"Americans have been brainwashed by the media, the clothing industry and the diet industry into thinking that thinness is a panacea," said Dr. Allon. "It's interesting to watch television. One commercial encourages people to eact calorie-rich food, the Next invites them to come and join a health spa to lose weight.

"Nearly every woman's magazine carries pictures and recipes for mouth-watering foods," she added, "but at the same time they advertise slimming fashions and page after page of diets."STDoctors who treat the obese are still not certain what causes obesity - which is rarely the result of a glandular disorder - or what is the best method of treatment. Medical schools are only now beginning to provide medical students with information on how to handle the obese patient.

For the most part, the business of weight control has been left in the hands of nonphysician "experts" who were once obese themselves, discovered a way to lose their own weight and now sell their dieting ideas to the public.

In cases of extreme obesity, doctors also may have their patients admitted to a hospital and placed on a strictly controlled diet. A procedure to wire the jaws of the patient has also been developed to prevent intake of anything but liquids.

In addition, between 5,000 and 20,000 obese persons each year undergo an intestinal bypass operation, which involves removing a section of the small intestine to reduce the body's ability to absorb nutrients.

However, the bypass operation has lost much of its original popularity in recent years because of a high number of deaths and complications that result.

In their book, "Practical Management of the Obese Patient," Doctors Frank L. Bigsby and Cayetano Muniz maintain that public attitudes toward obesity over the centuries have ranged widely from admiration and envy to laughter and condemnation.

In the pre-Christian ers, young people in Sparta were expelled from the city if they could not control their weight. During the middle ages, gluttony itself was regarded as a sin, but obesity was seen as a symbol of wealth and the "Grace of God."

Early in this century, Americans still looked upon fatness as a mark of success and virtue, but by World War I, public feeling had once again swung in opposition to overweight. Many stout women who worked in factories while the men were off to war found it difficult to squeeze into men's uniforms, the women found they were not very attractive.

When the war was over and rationing no longer set limits on their meals, Americans once again resumed their habit of overeating and quickly gained back the pounds many had shed during wartime. Slimness remained a social goal and large numbers of Americans, for the first time, began to think of obesity as a serious health threat.

Tom Greshen, whose huge six-foot frame dwarfed the full-sized sofa he sat on during a recent interview, was born in 1935 during a time when the big person was considered to be the healthy, happy person. It was thought by some during that period that excess fat could help fend off such diseases as tuberclosis.

Plump since childhood, Greshen said he developed his gargantuan appetite and taste for rich foods at home, where his parents - both of whom were slightly heavy - provided such fare in abundance.

Greshen said much of what he consumed as a child was quickly burned as energy needed for childhood word and play. During high school, he said his weight ranged up to about 225 pounds, which was not considered excessive for a "growing boy" of his age, height and towering body frame.

"About 13 years ago, i started picking up pounds that I found really hard to lose," said Greshen. "It was right at a time when a lot of my old habits were changing and I was taking on whole new life style.

"I started taking some college courses at night. That took away a tremendous amount of the time I had been using for fun and games - just blowing off steam.

"Then I switched jobs and went from testing hydraulic equipment, where I got a fair amount of exercise outside of the office, to a job baking ice cream cones for the CADO Division of the Maryland Cup Corporation. This is primarily a desk job. I rarely have an opportunity to burn off much energy."

(Greshen said his current job at the bakery, which pays $11,000 a year, sometimes requires him to taste ice cream cones with ice cream to check the product for quality and flavor."

"About the same time, I decided to stop smoking," Greshen continued.

"I had a lot to deal with at one time - regular family pressures, a new job, college homework and smoking withdrawal. I responded to everything by eating. Pretty soon, overeating became automatic, whether I was under pressure or not."

About 10 years ago, when his weight went beyond 250 pounds, Greshen said he began trying to cut back on his intake of high calorie foods. He said his will power soon gave way to the delicious meals of his wife, Maryan.

"I would go to the doctor," Greshen said, "and he would tell me that my problem is simple. He'd say, 'Tom you eat too much. here. Go home and follow this diet,' and he'd reach under his desk and pull out a standard diet and hand it to me."

Seven years ago, at a lumbering 300 pounds, Greshen said he turned to weight reducing clubs for help.

"I had some success with the weight classes," he said. "They helped me to get my weight down from 350 to 280 pounds using certain special diets. I was able to turn my weight problem around and I stopped gaining."

A short time later, Greshen said, he returned to his old eating habits and resumed gaining weight like more than 90 per cent of all persons who lose weight. Greshen said he tried to diet again, with no success. Then the eating binges started.

"I really don't know what triggered it," said Greshen. "It was a psychological or emotional thing, I guess. You know that your stomach is full and you are not hungry, but a strong compulsion strikes you and just keep eating until you're sick.

"I may not eat milk chocolate for a year. Then all of a sudden I get the urge so great that I rush out and buy five pounds of chocolate. I sit down and eat evey piece.

"The same thing happens with cheese cake, I don't buy one itty bitty piece," he said. "I buy the whole cheese cake. It takes me two days to eat it and I'm as sick as a dog for the next three days."

At regular meal times, Greshen said he dines royally on his wife's dishes of spaghetti and meat sauce one night, hot biscuits and chicken and dumplings the next, then perhaps a tuna casserole and baked beans and franks.

Greshen said his wife, Maryan, and his daughters, Katherine 14, and Lillian, 11, are all overweight. His son, Christopher, 17, is the only slender member of the family, he said.

"We all need to lose weight," Greshen said. "We would have the problem licked if we could agree to change our eating habits at the same time, but I don't think we're ready - as a family - to stop eating the things we enjoy."

A year ago, after all else had failed, Greshen and his wife began attending the Johns Hopkins University health and weight program, which takes the behavior modification approach to weight reduction.

"At Hopkins, we try to help the obese person understand what is causing his obesity," said Mrs. Simonson. "Then we try to eradicate the cause so that the person can begin to lose weight naturally and permanently."

Mrs. Simonson, who has reduced her own weight from 280 to 160 pounds, said she organized the program as an informal weight reduction group in 1969 after she failed to lose weight under the tutelage of a leading weight club.

"I had tried every diet there was and had just about ruined my health," she said. "The behavior approach worked in my case and we've been able to help thousands of other people as well."

Each Wednesday night, the Greshens take their place in a long line of overweight persons who attend the clinic. They come from five states and include Paul and Peggie Renoff, a well-to-do retired couple who provide some financial backing for the program and fly in from Florida; a college professor who commutes to the program from New Hampshire, and a Texas oil man who flies into Baltimore in his private jet.

One by one, the "patients" weigh in to register any degree of weight loss or gain during the seven days since their last meeting.

The clinic is financed by the university, private foundations and private citizens. Poor people, who comprise the majority of the class, are admitted without charge. Others pay a token $1 tuition.

So far, more than 9,000 persons have passed through the program, most of them emerging with some weight loss and the nutritional knowledge they need to make educated decisions about what and how they eat, Mrs. Simonson said. They have all heard her opening lecture.

"We are here to teach you the dynamics of obesity; what causes it; and why fat settles in certain places," said Mrs. Simonson, who spoke in preaching tones and sometimes pounded on the rostrum to emphasize her point.

"I am interested in you as human beings," she told the group who sat in absolute silence. "I only hope you will use your God-given intelligence to take the information we will give to you and use it to improve and perhaps save your own lives."

NEXT: The Disease of Obesity.