When most people think of obesity, they think of adults, and it's true that adult obesity is one of our major and most difficult health problems. In fact, between 30 and 40 percent of adult Americans are significantly overweight, and the number appears to be growing. But obesity is also a big problem with children. By current statistics, about one out of four youngsters is obese, and the alarming fact is that this figure, too, is on the rise.

In children, as in adults, obesity is both an emotional and a physical burden. Any number of reports have indicated that adults unconsciously shy away from fat children. And studies done by Dr. Mayer show that obese high school students have less chance of gaining acceptance into college (when their obesity is known) than students of normal weight who are equally qualified. Other studies have shown that even kindergarten children find fat children less desirable as playmates. Little wonder that some investigators have found that obese children exhibit more personality disturbances.

As far as physical health is concerned, an overwhelming majority of obese children - as many as four out of five - become fat adults. And overweight is directly linked to some of our most serious diseases in adulthood - coronary heart disease, hypertension and diabetes. It's obvious then, for all these reasons, that it is just as important to control obesity during childhood as it is in the adult years.

But as with adults, controlling obesity in children is not easy. The difficulty is compounded by the fact that children must get plenty of calories and nutrients for proper growth, but not so much that they develop patterns of overeating and put on excess weight.

Over the last few years, the use of what is called "behavioral modification" has become an accepted part of many dieting regimens for adults. The basic idea is that to be successful in dieting, it is as important to change eating habits as it is to change caloric intake. By "successful," of course, we mean a diet that not only gets the weight off but also keeps it off.

Behavioral modification was pioneered by one of our former colleagues, Dr. Albert Stunkard of the Department of Psychiatry at the University of Pennsylvania. Coupled with a total program of exercise and a balanced reducing diet, behavioral modification has proved to be a promising adjunct to dieting regimens for adults. Now the method is being tried with children.

In a recent article in the American Journal of Diseases of Children, Dr. Stunkard and his associate, Dr. Kelly Brownell, assessed the effectiveness of several experimental approaches to behavioral treatment of childhood obesity - all of which show signs of success.

In one research study, a group of chronically overweight children from low-income families were asked to keep a daily record of what they ate as well as the caloric content. They were also instructed to eat more slowly and put their untensils down between bites as a further means of curbing their normal eating habits. The average weight loss was about five pounds. Interestingly, the children whose mothers were normal weight lost more than those whose mothers were overweight.

Another research study sought to evaluate what added effect there is when parents participate with their children in attempting to alter "food behavior." In this study, one group of children attended the clinic alone; in a second group, mothers came by themselves and then instructed their children at home, and in a third group, mothers and children attended together. Analysis of the results showed that there was no significant difference among the three groups. The results were equally good, but the group with both children and mothers attending the clinic together reported the greatest satisfaction with the treatment. Incidentally, as an added bonus, the mothers in the "mothers only" group also lost weight!

In yet another study with overweight adolescent girls, it was shown that highly individualized treatment may be more successful than group therapy. This finding is in contrast to the experience of weight-control clinics and groups like Wwight Watchers, where groups treatment is more successful for adults.

With children, the goal of dieting is not measured by weight loss alone, but by loss of excess fat, plus the slowing down of weight gain. The idea is to get down to a normal rate of weight gain in order to meet the needs of growth and good health. The best and safest method is to combine exercise with a moderate diet. And it appears from these very preliminary reports that behavioral modification therapy can be as useful for overweight children as it has already become for obese adults.