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Obesity in Adolescence
Obesity in Adolescence JEAN MAYER, PH.D., D.Sc.*
There is no general agreement, even within the United States, on a satisfactory standard for growth. This may arise from the fact that height-weight relationships alone, which have served as the usual basis of such standards-with little or no attention being given to somatotypes, maturational age or fat content of the body-cannot be relied on to provide universally applicable guides. Some height-weight tables have included indices which take body build into account. Pryor31 included chest circumference and pelvic breadth. Bayer and Gray's2 charts included a bicristal diameter determination. The Pryor tables have been criticized34 on the basis that, for increasingly obese children with increasingly larger chest circumferences and pelvic breadth, expected weights will rise excessively. The Stuart-Meredith charts38 include separate tables for chest circumference, hip width and calf girth; this permits a better assessment of the individual pattern of growth when longitudinal records are established. The Wetzel grid,45 constructed on a log-log scale, combines height and weight data on one scale and developmental level in relation to chronological age on a second. This well-known grid is intended for longitudinal studies of an individual; it plots the height-weight relationship within channels; the expected growth should take place within one such channel. Specifically, Wetzel states: "It may be stated as a simple and practical rule that normal variations do not exceed one-half channel per 10 units of development." "Obesity" is defined as starting at the ~ channel. The Wetzel grid has been criticized on a variety of grounds. Garn12 has shown that changes from channel to channel are more frequent than Wetzel indicated. Solley came to the same conclusions for at least the younger children. Perhaps a more serious objection is the fact that weight* Consultant in Nutrition, The Adolescents' Unit, Children's Hospital Medical Center; Associate Professor of Nutrition, Harvard University School of Public Health, Boston, Massachusetts
PUBLISHERS' NOTE: This talk, delivered by Dr. Mayer as part of the course, "The Medieal Care of the Adolescent," was modeled closely after his paper of similar title appearing in the September, 1964 issue of this publication. It is repeated here to bring the full picture of adolescents' medical care within one cover.
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height relationships tell little about body composition; muscularity and adiposity are treated in equivalent manner; and while the grid may be useful for some population studies, it is of limited value for individuals. A number of uncoordinated attempts to get at the actual fat content of children has been made. These are far fewer and more difficult to interpret than are comparable studies of adults. For example, ZOOk46 made some determinations of specific gravity by underwater weighings of children. The unusually high fat contents calculated from these determinations are probably traceable to inadequate corrections for residual air. Friis-Hansen and his co-workers u have attempted to derive predictive equations for total body water in children up to age 11 on the basis of some determinations. Macy and Kelly19 have adapted "adult" equations for the calculation of lean body mass on the basis of creatinine excretion studies. In the absence of well-established standards, subcutaneous thicknesses appear to give the most reliable (and certainly the easiest to obtain) basis for the diagnosis of obesity in children. Reynolds and Asakawa 52 combined subcutaneous tissue in six body sites with other body measurements to try to establish a classification of obesity. The numbers studied were small50-and their divisions "obese," "mixed obese," "relatively obese," "relatively mixed obese," and "not obese" lack descriptive value. Hunt, Peckos and Fry l5 and Stefanik, Heald and Mayer 36 have used either the presence of fat pads, as viewed in somatotype pictures in various sites, or the sum of skinfold thicknesses at various sites as an arbitrary criterion for presence or absence of obesity, but a statistical foundation for such empirical diagnoses was missing. A study recently published gives a rational basis for more systematic standards. Tannel and Whitehouse43 have presented data on no fewer than 25,000 children, almost all of whom were British, from one month to 1672 years of age. The great majority were London school children above five, with a few hundred children enrolled in a special child study group. Measurements of triceps skinfold (just below the angle of the left scapula) were made by trained personnel using Harpenden constant-pressure calipers. From these, Tanner and Whitehouse established age curves for the third, tenth, twenty-fifth, fiftieth, seventy-fifth, ninetieth, and ninety-seventh percentiles. Variability is considerable. The British authors found that in 12 year old boys, for example, triceps skinfold thickness varies from 4.5 mm. at the third percentile to 22 mm. at the ninety-seventh, with a fiftieth percentile of 9 mm.; the corresponding values for girls are 4.5,25 and 8 mm., respectively. Age trends conform to expected norms; for triceps skinfold of boys, the fiftieth percentile is 6 mm. at one month, rises to 10.5 mm. at one year, fades slowly to 7.5 by age 7, then rises to 9 at 12.5 years and falls back to 7.5 by age 16.5 years. Values for girls for these same ages are 6.5, 10.5, 9, 10.5 and 14.5 mm. respectively. The variation of subscapular fat parallels that of triceps skinfold until age 7; from then on it shows a
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steady rise. Subscapular skinfold thickness exceeds that of boys at all ages, confirming that girls are fatter than boys from at least age two onward. While the British authors would doubtless agree that much remains to be done, particularly from the viewpoints of somatotyping and maturational age, their work permits the definition of at least comparative obesity at the various age groups and is thus a major contribution. CONSTITUTIONAL AND PHYSIOLOGIC FACTORS IN THE ETIOLOGY OF OBESITY
The complexity of the problem of the regulation of food intake is well known. 26 Any mechanism so intricate can obviously get out of order in a variety of ways. In other reviews devoted to obesity in general, it has been shown that a convenient classification of obesities can be based on the etiology of known types: one can then distinguish between genetic, traumatic and environmental factors in obesity.20 Another way of looking at obesities is to consider pathogenesis. One can then consider "regulatory" obesities, where the error is in the mechanisms, neurological and psychophysiological, which regulate food intake, and "metabolic" obesities, '" here the error is in the handling of metabolites, particularly carbohydrates and lipids. 22 Both of these types are illustrated by a number of experimental situations which have been studied in detail in the present writer's laboratory.25 Interesting suggestions that a similar distinction between the two classes is justified in man are dealt with elsewhere in this volume. Typing of obesity on the basis of anthropometric and metabolic factors is pursued actively in our laboratory. Consideration of body types and pattern of excretion of 17-ketogenic steroid may permit separation of at least one distinct form of obesity in adolescent girls from the other forms.B6 The probability that various modes of transmission of genetic factors predisposing to obesity are found in the human species as well as in animal species has been discussed at length elsewhere,24 and will not be recalled here. It is sufficient to recall that, in the Boston area, approximately 10 per cent of the children of parents of normal weight are obese at age 15, 40 per cent if one parent is obese, 80 per cent if both are obese, and that there are cogent reasons to think that these figures are due at least as much to heredity as to environment. PSYCHOLOGICAL FACTORS IN THE ETIOLOGY OF OBESITY IN CHILDHOOD
One of the ablest psychologists in the field of childhood obesity, Hilde Bruch5 • 6, 7 has classified the possibilities of associating body weight and
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adjustment in the following fashion: (1) slenderness with good adjustment; (2) slenderness with poor emotional adjustment; (3) continued obesity, usually of moderate degree, with good adjustment; and (4) continued obesity with maladjustment. In her thinking, continued obesity with good adjustment represents a "constitutional" obesity compatible with an otherwise normal personality. She assumes the obesity in this case to be due essentially to physiologic factors. Patients of this type are usually obese from childhood and stay continuously heavy, with their height and weight moving steadily in the overweight area of the growth diagram. They function adequately with this degree of obesity. Bruch believes that, in such patients, psychologic difficulties are likely to arise or to become serious only if they are forcibly reduced. The situation is quite different in what Bruch terms "reactive" obesity and in "developmental" obesity of nonconstitutional origin. She believes that in reactive obesity, overeating is a response to and a compensation for tension and frustration. In many patients, as Stunkard and Dorris40 have also emphasized, the situations leading to overeating also provoke a drastic decrease in activity. Both these factors are synergistic in causing markedly positive caloric balance. Episodes of grief or of severe depression thus coincide with drastic elevations of weight. As this type of obese patient does, in fact, tend to become depressed easily, a considerable degree of obesity can develop in a few years. Bruch considers this reactive obesity the characteristic form of psychologic obesity in adulthood and middle age. She has observed few instances of reactive obesity in childhood. Stunkard, Grace and W0lff39 emphasized that among such potentially depressed, reactive obese patients they frequently found a distinctive eating pattern which they called the "night eating syndrome." In a study conducted a few years ago in Boston, Dr. Beaudoin and P observed that an unselected group of obese women tended to distribute their calories so that proportionally they consumed more during the later hours of the day. Stunkard showed that this effect was particularly marked in obesity associated with frequent bouts of depression. In many such patients, the actual bulk of the daily calories may be consumed in the evening hours and at night, which are also the periods of the day when depression is most severe. Stunkard and Wolff showed that, in addition to this characteristic eating pattern and the decreased activity during periods of intense depression, this type of obese patient exhibits in many instances drastic changes in carbohydrate metabolism, particularly abnormally increased glucose tolerance, which coincide with the episodes of drastic weight gain. It is thus possible that physiologic changes mediate in many of these patients the psychologic trauma which indirectly leads to overeating. Interaction between psychologic and endocrine factors may explain why certain patients will tend to
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accumulate considerable excess weight during a period of grief while others faced with the same trauma may lose weight. Developmental obes£ty is described by Bruch as a common form of obesity during childhood. She believes that, in many obese children in whom the obesity is not due to purely physiologic factors, the emotional development centcrs around eating as much as they want, avoiding physical activity and social contacts, and being fat. She feels that, usually, such children are growing in a family setting in which they are used by one or the other parent (sometimes by both) as an object fulfilling his needs and compensating for failure and frustration in his own life. The child is fussed over excessively, overprotected and overfed. Generally, the mother plays the dominant role in the emotional life of such families; she indulges the obese child and keeps him close to her by constant and excessive demands. Thus, she considers that the problems of children of this type are not unlike those seen in the premorbid stage of schizophrenia. The combination of this environment and of being obese tends to promote a sense of helplessness and inadequacy which causes flight into fancy and sometimes hostility and sadism. This speaker, while admiring the diligence and care with which Hilde Bruch has collected and analyzed her material, feels that her generalizations are too broad. Psychiatrists, by the very nature of their profession, tend to see children who are psychologically outside of the more normal range seen by nutritionists, physiologists and general clinicians. Quaade, whose book on "Obese Children" is well documented, finds himself unable to confirm many of Bruch's observations. For example, to pick a striking illustration, unlike Bruch he finds in his material no more obese children among the enuretics than among normal children. He does not find in his large-scale study any confirmation for Bruch's idea that being an only child, having a peculiar family position, insufficient suckling, prolonged bottle feeding, death among the siblings, or surgical operations have any statistical relevance to the presence or absence of obesity. He feels that the fact that he examines obese children in the general population rather than psychiatric clinic patients is the cause of the discrepancy of his results with those of Bruch and of other psychiatrists. PSYCHOLOGIC ASPECTS OF BEING OBESE IN CHILDHOOD AND ADOLESCENCE
It is dangerous to underestimate the psychologic effects of the pressures of society on the obese adolescent, the obese girl in particular. The importance of these pressures and their damaging effects on the psyche of obese children were dramatically illustrated in a recent study conducted by
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Monello and Mayer27 on 100 obese girls in a weight.-reduction camp 30 and 65 nonobese controls from a typical summer camp. Three projective tests were administered in group situations: word association, sentence completion and picture description tests. The results of these tests revealed that obese girls showed personality characteristics strikingly similar to the traits of ethnic and racial minorities recognized by Gordon Allport and others as due to their status as victims of intense prejudice. One such trait is "obsessive concern": heightened sensitivity and preoccupation with one's status, exemplified in the tests by numerous word association responses concerned with such words as calories, diet, reducing, fattening, fat, heavy, overweight. Another such trait is "passivity" shown by the obese girls in their mode of response in picture description tests. "Withdrawal," the obese group's isolation and feeling of rejection by their peers, again was illustrated by the picture description responses. The obese girls also shared "acceptance of dominant values" and considered obesity-and hence their own body-as undesirable and somewhat harmful. The lack of an "ingroup," particularly the lack of family support, actually seems to expose the obese youngsters to greater tension than youngsters belonging to minority groups. The obese youngsters thus appear to be in an ambivalent situation vis a vis their own family of both greater dependence than in the case of the nonobese and at the same time greater tension. These findings may be related to those of Stunkard and Mendelson,42 who have observed obese subjects with "distorted body images" who exhibit attitudes remarkably similar to "obsessive concern" and "identification with the dominant group" noted in ethnic and racial minorities. They show an exaggerated preoccupation with weight; they judge people in terms of weight, feeling contempt for fat people and admiration for thin people, and they feel their obesity is a handicap responsible for all disappointments. Subjects displaying such attitudes had all been obese since childhood or adolescence, while suhjects failing to display such attitudes had all become obese as adults. The crucial difference between these two groups may be the extent to which punitive social pressures have affected their personalities. Children and adolescents are sensitive to such pressure and would be expected to respond more strongly than adults. It is important to keep in mind that obese youngsters, in our society, however casual and relaxed they may appear at first sight, often feel quite intensely a heavy burden of self-blame and inferiority. It is essential that the therapist not add unwittingly to this burden. Such ill-considered action can only, in the light of the finding reported above, increase such traits as passivity and withdrawal, compound the trend to physical inactivity and thus make this difficult condition even more difficult to treat. Finally, it is perhaps useful to mention that observations of patients with anorexia nervosa suggest that they present a number of characteristics
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similar to those observed in obese adolescent girls. Such patients may be characterized by what is called a "triad of denials": denial of excessive thinness, denial of hunger and denial of fatigue. The denial of excessive thinness is a consequence of a disturbance of body image which appears to be the result of panic fear of obesity: in spite of the patient's emaciation, she sees herself as hardly gaining in her unending fight against fatness. This, in turn, may well be closely akin to the obsessive concern with her appearance, typical of the obese adolescent, superimposed on a compulsive, perfectionist personality. The denial of hunger is similar to that described by Stunkard41 in many obese patients. The denial of fatigue takes place in spite of the highly ritualized, excessive exercise performed by a famished, sometimes debilitated body. When the patient is interviewed, it becomes obvious that social pressures against obesity play a major part in the etiology of the syndrome, with the trigger often provided by a chance remark of a key male figure. Thus both the behavior of the patient with anorexia nervosa as well as that of the obese youngster makes it apparent that any campaign against obesity or any treatment of the obese youngster must be performed with tact, and that the 'i:ndividual patient must be known and followed carefully so as to make sure that the medical and cosmetic advantages of weight reduction are not counterbalanced by psychological trauma. PERSISTENCE OF CHILDHOOD OBESITY
There is relatively little evidence on the course of development of obesity starting at various ages. Mullins,29 in a rctrospective study of obese patients in a London outpatient clinic, found that among 373 consecutive outpatient admissions, 26 per cent of the men and 44 per cent of the women were more than 20 per cent above "standard" weight. Approximately one-third of these patients had been obese from childhood. These patients showed a high incidence of psychological abnormalities as evaluated by clinical examination. The clinical impression also suggested that intelligence and extent of schooling were much less in the group that had been obese since childhood. While this study is of obvious interest, it must be noted that the criterion for obesity in childhood was very poor-the patients had been called "fatty." No systematic attempt was made to evaluate the possible differences in persistence associated with time of onset. Finally, the observation on the intelligence of the obese patients is at variance with the more systematic study: we could not find differences in school grades (other than physical education) between obese and nonobese high school students. A more objective evaluation of the persistence of childhood obesity
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was conducted by Abraham and Nordsieck. 1 They used height-weight records secured in children in three elementary schools in Hagerstown, Maryland, from 1937 to 1939 as their basis. These records covered 2000 boys and girls between the ages of 10 and 13. Heights were determined without shoes, and weight without shoes, sweaters and coats. Heights and weights were compared to the Baldwin-Wood averages. Fifty of the heaviest children of each sex, amounting to 5 per cent of the total, were selected as overweight. Fifty children of each sex were chosen for the "average weight" group. Only 120 of these 200 children could, however, be located at the time of the study (1960); the average age was 31 years (range 26 to 35). The results in this admittedly small group were clear-cut and showed that obesity in childhood tends to be persistent in adulthood: of the extremely overweight boys, 86 per cent were overweight as adults. Of the average weight boys, 42 per cent were overweight as adults. Among girls, 80 per cent of the extremely overweight children were overweight as adults, while only 18 per cent of the average weight children became overweight as adults. It must be noted, however, that 50 per cent of a group of moderately overweight girls were average weight or less as adults which suggests that obesity is more persistent if it is more extreme, or alternately that different syndromes are involved. A weakness of this study is that, again, it fails to differentiate between the fates of subjects in whom obesity started at various ages. Other studies, again on relatively small numbers, reported by Lloyd, Wolff and Whelen18 in Britain, by Haase and Rosenfeld13 in Germany, and by Mossberg28 in Sweden, emphasize the persistence in adulthood of most obesity cases seen in childhood, and offer suggestive evidence that this is particularly so for girls. My impression, developed in the course of studies of obesity in children over a span of many years, is that obesity which develops in the younger age groups (e.g., before 10 or after 16) has a somber prognosis for eventual weight reduction, while obesity developing just before the onset of puberty may be an exaggeration of a normal physiologic process and is often benign and self-correcting in the next few years. INACTIVITY AS A CAUSE OF OBESITY IN CHILDREN AND ADOLESCENTS
A decreased tendency for muscular activity was observed by Rony33 to be a common finding among many obese persons. He also noted that, as weight increases, the impulse for physical exertion decreases. Bruch4 rightly called attention to the relative inactivity of many obese children. Few quantitative data, however, were adduced to substantiate this statement.
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A physiologic basis for the reassessment of the possible vrimary contribution of inactivity as a cause of obesity appeared when work done in our laboratory demonstrated that, when activity is reduced to below a minimum level in experimental animals 2l and in adult men,23 a corresponding decrease in food intake does not result and obesity develops. (Actually, at very low levels of activity, in experimental animals as in men, food intake tends to increase-a phenomenon long known by farmers who "coop up" or "pen up" animals they want to fatten. This phenomenon may be interpreted in the framework of a glucostatic mechanism in the regulation of food intake, as Christophe and Mayer lO have shown that inactivity reduces glucose utilization.) It was also shown that genetically obese mice are extremely inactive, and that, conversely, exercising them (and animals with other forms of experimental obesity as well) causes spontaneous weight loss. Johnson, Burke and Mayerl7 found that the onset of excessive weight gain among obese children in the public schools of Newton and Brookline (Massachusetts) generally occurred durin~ the winter; this suggested that inactivity might be an important factor in the development of obesity. A more detailed studyl6 involving the comparison of food intake and activity schedules of 28 obese high school girls selected from this population with controls of normal weight and of the same height, age, school grades and socioeconomic status, showed that these gi.rls ate less, not more, than their normal weight controls but spent a strikingly smaller amount of time (two-thirds less) in occupations involving any amount of exercise. Similarly, Stefanik, Heald and Mayer,36 studying the food intake and amount and degree of participation of 14 obese adolescent boys and 14 paired nonobese controls at a summer camp, found both a significantly smaller intake and a smaller degree of participation in exercise among the obese boys. Stefanik et al.37 found that increased exercise made a group of adolescent girls lose weight (as well, incidentally, as lose subcutaneous fat at scapular and abdominal but not arm sites). Bullen,8 using a new technique developed for time-motion studies in industry and involving the taking of a number of photographs which are then used as a basis for the estimation of caloric expenditures based on the particular pose represented, has been able to demonstrate unequivocally that the average obese adolescent girl expends far less energy during scheduled "exercise" periods than does her nonobese counterpart. The facts that school buses and individual means of transportation are now available to almost all youngsters, that physical chores are no longer required, and that physical education programs are short and inadequate make this inactivity (which is not restricted to children) of considerable importance in the interpretation of the prevalence of obesity in our youngsters.
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The explanation of this widespread inactivity, however, is a difficult task. For one thing, just as hyperphagia admits of many different explanations, so probably, does inactivity. A priori, causes of this inactivity may be physiological or they may be psychological, or both. Furthermore, a permissive environment which no longer makes activity compulsory for survival must be present. At present, studies into causes of inactivity in youngsters are limited. Bullen et al. 9 have studied the attitudes of a group of obese adolescent girls attending a summer camp and compared them to those of a similar group of nonobese adolescent girls. The two groups completed two types of tests: a direct questionnaire administered at the beginning and end of the camp season. Very generally, the responses of the nonobese group to the questionnaire implied a family life of sociability and unity while their responses to the projective tests indicated that they had little difficulty separating from the family. In contrast, the obese group depicted a less unified family which the child was afraid to leave. The obese youngsters were aware that they were inactive, though they had no conception of the degree of their inactivity. They seemed totally unaware that they might not like physical activity (or, for that matter, that there is a relationship between inactivity and obesity). Their attitude toward eating was of interest: they were concerned about food getting but often linked it-unlike the nonobese girls-with unpleasant consequences. Even though this group of obese subjects was not generally characterized by abnormally high food intake, the obese girls said that they ate more than average and considered it the cause of their obesity. It is thus obvious that these youngsters reflect popular ideas on the subject, and that their ignorance of the state of affairs concerning their extreme inactivity is of itself a factor militating against successful treatment. Obviously, much more work is needed in this area of primary psychological factors if the etiology of the inactivity is going to be separated from the psychological effects of the obesity, which themselves tend to make the child feel rejected and hence nonparticipating in group activities and sports. An intriguing recent finding suggests a possible physiological cause (or concomitant effect) of inactivity. Wenzel, Stults and Mayer44 have found that, in an outpatient adolescent clinic population, obese youngsters had a significantly lower serum iron (with normal hemoglobin) than did nonanemic, nonobese subjects. Seltzer and Mayer34 found similar differences between larger groups of obese and nonobese adolescent girls at summer camp. Whether these low serum iron values are indicative of low myoglobin values and low values for iron-containing pigments other than hemoglobin, is not known. If they were, they might signal a situation in which, in a society tolerant of physical inactivity, exercise would be unconsciously avoided. Again, much additional research is necessary on this point before even tentative conclusions are arrived at.
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ACKNOWLEDGMENT
The author acknowledges with many thanks permission from Annual Reviews) Inc. to include excerpts from his paper published in The Annual Review of Medicine, 1963.
REFERENCES 1. Abraham, S. and Nordsieck, M.: Relationship of excess weight in children and
adults. Pub. Health. Rep. 75: 263, 1960. 2. Bayer, L. M. and Gray, H.: Plotting of a graphic record of growth for children aged from 1 to 19 years. Am. J. Dis. Child. 50: 1408, 1935. 3. Beaudoin, R. and Mayer, J.: Food intakes of obese and nonobese women. J. Am. Dietet. A. 29: 29, 1953. 4. Bruch, H.: Physiological and psychological aspects of food intake of obese children. Am. J. Dis. Child. 59: 739, 1940. 5. Bruch, H.: Fat children grown up. The J ohns Hopkins Medical and Surgical Association, Baltimore, Feb. 25, 1955. 6. Bruch, H.: Psychopathology of Hunger and Appetite in Changing Concepts of Psychoanalytic Medicine. New York, Grune & Stratton, 1956. 7. Bruch, H.: The Importance of Overweight. New York, W. W. Norton & Co., 1957. 8. Bullen, B., Reed, R. B. and Mayer, J.: Physical activity of obese and nonobese adolescent girls appraised by motion picture sampling. Am. J. Clin. Nutrition 14: 211,1964. 9. Bullen, B. A., Monello, L. F., Cohen, H. and Mayer, J.: Attitudes toward physical activity, food and family in obese and nonobese adolescent girls. Am. J. Clin. Nutrition 12: 1, 1963. 10. Christophe, J. and Mayer, J.: Effect of exercise on glucose uptake in rats and men. J. AppI. PhysioI. 13: 269, 1958. 11. Friis-Hansen, B. J., Holiday, M., Stapleton, T. and Wallace, W.: Total body water in children. Pediatrics 7: 321, 1951. 12. Garn, S. M.: Individual and group deviations from "channel wise" grid progression in girls. Child Develop. 23: 193, 1952. 13. Haase, K. E. and Rosenfeld, H. Z.: Zur fettsucht in kindesalter. Ztschr. Kinderh. 78: 1, 1956. 14. Hathaway, M. L.: Heights and weights of children and youths in the United States. U.S. Dept. Agr., Home Econ. Res. Rep. No. 2, 1957. 15. Hunt, E., Peckos, P. and Fry, P.: Factors in Human Obesity and Nutrition. Symposium Series No. 6, National Vitamin Foundation, New York, 1953. 15a. Jacobsen, G., Seltzer, C.C., Bondy, P. and Mayer, J.: Importance of body characteristics in the excretion of 17-ketosteroids and 17-kobegenic steroids in obesity. New England J. Med. 271: 651, 1964. 16. Johnson, M. L., Burke, B. S. and Mayer, J.: Relative importance of inactivity and overeating in the energy balance of obese high school girls. Am. J. Clin. Nutrition 4: 37, 1956. 17. Johnson, M. L., Burke, B. S. and Mayer, J.: Incidence and prevalence of obesity in a section of school children in the Boston area. Am. J. Clin. Nutrition 4: 231, 1956. 18. Lloyd, J. K., Wolff, O. H. and Whelen, W. S.: Childhood obesity. Brit. M. J. 5245: 145, 1961. 19. Macy, I. G. and Kelly, H. J.: Body composition in childhood. Human BioI. 28: 289,1956. 20. Mayer, J.: Genetic, traumatic and environmental factors in the etiology of obesity. PhysioI. Rev. 33: 472, 1953.
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21. Mayer, J., Marshall, N. B., Vitale, J. J., Christensen, J. H., Masayeki, M. B. and Stare, F. J.: Food intake and body weight in normal rats and genetically obese adult mice. Am J Physiol. 177: 544, 1954. 22. Mayer, J.: The physiological basis of obesity and leanness. Nutrition Abstr. & Rev. 25: 597,87],1955. 23. Mayer, J., Roy, P. and Mitra, K. P.: Relation between caloric intake, body weight and physical work in an industrial male population in West Bengal. Am. J. Clin. Nutrition 4: 169, 1956. 24. Mayer, J.: Correlation between metabolism and feeding behavior and multiple etiology of obesity. Bull. New York Acad. Med. 83: 744,1957. 25. Mayer, J.: Obesity. Ann. Rev. Med. 14: 111, 1963. 26. Mayer, J. and Hanson, S. D.: Unpublished results. 27. Monello, L. F. and Mayer, J.: Obese adolescent girls: an unrecognized "minority" group? Am. J. Clin. Nutrition 13: 35, 1963. 28. Mossberg, H. 0.: Obesity in children: A clinical-prognostical investigation. Acta paediat. 35 (Suppl. 2): 9, 1948. 29. Mullins, A. G.: Prognosis in juvenile obesity. Nutrition Rev. 17: 99, 1959. 30. Peckos, P., Spargo, J. and Heald, F.: Program and results of a camp for obese adolescent girls. Postgrad. Med. 27: 527, 1960. 31. Pryor, H. B.: Height-Weight Tables for Boys and Girls from 1-17 Years; for Men and Women from 18-41 plus Years. Stanford, Calif., Stanford Univ. Press, 1940. 32. Reynolds, E. L. and Asakawa, T.: Measurement of obesity in childhood. Am. J. Phys. Anthropol. 6: 475, 1948. 33. Rony, H. R.: Obesity and Leanness. Philadelphia, Lea & Febiger, 1940. 34. Seltzer, C. C. and Mayer, J.: Serum iron and iron-binding capacity in adolescents. n. Comparison of obese and nonobese subjects. Am. J. Clin. Nutrition 18: 354, 1963. 35. See Reference 15a. 36. Stefanik, P. A., HeaId, F. P., Jr. and Mayer, J.: Caloric intake in relation to energy output of nonobese and obese adolescent boys. Am. J. Clin. Nutrition 7: 55,1959. 37. Stefanik. P. A., Bullen, P. A., Heald, F. P., Jr. and Mayer, J.: Observations on physical performance, skinfold measurements, activity expenditures and food consumption of college women. Res. Quart., Am. A. for Health, Physical Education and Recreation 32: 229, 1961. 38. Stuart, H. C. and Meredith, H. V.: Use of body measurements in the school health program. Am. J. Pub. Health 36: 1365, 1946. 39. Stunkard, A. J., Grace, W. J. and Wolff, H. G.: The night eating syndrome: Pattern of food intake among certain obese persons. Am. J. Med. 19: 78, 1955. 40. Stunkard, A. J. and Dorris, R. J.: Physical activity: Performance and attitude of a group of obese women. Am. J. M. Sc. 233: 622, 1957. 41. Stunkard, A. J. and Wolff, H. G.: Pathogenesis in human obesity. Psychosom. Med. 20: 17,1958. 42. Stunkard, A. J. and Mendelson, M.: Disturbances in body image of some obese persons. J. Am. Dietet. A. 38: 328, 1961. 43. Tanner, J. M. and Whitehouse, R. H.: Standards for subcutaneous fat in British children. Brit. M. J. 1: 446, 1962. 44. Wenzel, B. J., Stults, H. and Mayer, J.: Hypoferremia in obese adolescents. Lancet 2: 327, 1962. 45. Wetzel, N. C.: Physical fitness in terms of physique, development and basal metabolism. J.A.M.A. 116: 1187, 1941. 46. Zook, D. E.: The physical growth of boys: A study by means of water displacement. Am. J. Dis. Child. 43: 1347, 1932. One Shattuck Street Boston 15, Massachusetts
There is no general agreement, even within the United States, on a satisfactory standard for growth. This may arise from the fact that height-weight relationships alone, which have served as the usual basis of such standards-with little or no attention being given to somatotypes, maturational age or fat content of the body-cannot be relied on to provide universally applicable guides. Some height-weight tables have included indices which take body build into account. Pryor31 included chest circumference and pelvic breadth. Bayer and Gray's2 charts included a bicristal diameter determination. The Pryor tables have been criticized34 on the basis that, for increasingly obese children with increasingly larger chest circumferences and pelvic breadth, expected weights will rise excessively. The Stuart-Meredith charts38 include separate tables for chest circumference, hip width and calf girth; this permits a better assessment of the individual pattern of growth when longitudinal records are established. The Wetzel grid,45 constructed on a log-log scale, combines height and weight data on one scale and developmental level in relation to chronological age on a second. This well-known grid is intended for longitudinal studies of an individual; it plots the height-weight relationship within channels; the expected growth should take place within one such channel. Specifically, Wetzel states: "It may be stated as a simple and practical rule that normal variations do not exceed one-half channel per 10 units of development." "Obesity" is defined as starting at the ~ channel. The Wetzel grid has been criticized on a variety of grounds. Garn12 has shown that changes from channel to channel are more frequent than Wetzel indicated. Solley came to the same conclusions for at least the younger children. Perhaps a more serious objection is the fact that weight* Consultant in Nutrition, The Adolescents' Unit, Children's Hospital Medical Center; Associate Professor of Nutrition, Harvard University School of Public Health, Boston, Massachusetts
PUBLISHERS' NOTE: This talk, delivered by Dr. Mayer as part of the course, "The Medieal Care of the Adolescent," was modeled closely after his paper of similar title appearing in the September, 1964 issue of this publication. It is repeated here to bring the full picture of adolescents' medical care within one cover.
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height relationships tell little about body composition; muscularity and adiposity are treated in equivalent manner; and while the grid may be useful for some population studies, it is of limited value for individuals. A number of uncoordinated attempts to get at the actual fat content of children has been made. These are far fewer and more difficult to interpret than are comparable studies of adults. For example, ZOOk46 made some determinations of specific gravity by underwater weighings of children. The unusually high fat contents calculated from these determinations are probably traceable to inadequate corrections for residual air. Friis-Hansen and his co-workers u have attempted to derive predictive equations for total body water in children up to age 11 on the basis of some determinations. Macy and Kelly19 have adapted "adult" equations for the calculation of lean body mass on the basis of creatinine excretion studies. In the absence of well-established standards, subcutaneous thicknesses appear to give the most reliable (and certainly the easiest to obtain) basis for the diagnosis of obesity in children. Reynolds and Asakawa 52 combined subcutaneous tissue in six body sites with other body measurements to try to establish a classification of obesity. The numbers studied were small50-and their divisions "obese," "mixed obese," "relatively obese," "relatively mixed obese," and "not obese" lack descriptive value. Hunt, Peckos and Fry l5 and Stefanik, Heald and Mayer 36 have used either the presence of fat pads, as viewed in somatotype pictures in various sites, or the sum of skinfold thicknesses at various sites as an arbitrary criterion for presence or absence of obesity, but a statistical foundation for such empirical diagnoses was missing. A study recently published gives a rational basis for more systematic standards. Tannel and Whitehouse43 have presented data on no fewer than 25,000 children, almost all of whom were British, from one month to 1672 years of age. The great majority were London school children above five, with a few hundred children enrolled in a special child study group. Measurements of triceps skinfold (just below the angle of the left scapula) were made by trained personnel using Harpenden constant-pressure calipers. From these, Tanner and Whitehouse established age curves for the third, tenth, twenty-fifth, fiftieth, seventy-fifth, ninetieth, and ninety-seventh percentiles. Variability is considerable. The British authors found that in 12 year old boys, for example, triceps skinfold thickness varies from 4.5 mm. at the third percentile to 22 mm. at the ninety-seventh, with a fiftieth percentile of 9 mm.; the corresponding values for girls are 4.5,25 and 8 mm., respectively. Age trends conform to expected norms; for triceps skinfold of boys, the fiftieth percentile is 6 mm. at one month, rises to 10.5 mm. at one year, fades slowly to 7.5 by age 7, then rises to 9 at 12.5 years and falls back to 7.5 by age 16.5 years. Values for girls for these same ages are 6.5, 10.5, 9, 10.5 and 14.5 mm. respectively. The variation of subscapular fat parallels that of triceps skinfold until age 7; from then on it shows a
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steady rise. Subscapular skinfold thickness exceeds that of boys at all ages, confirming that girls are fatter than boys from at least age two onward. While the British authors would doubtless agree that much remains to be done, particularly from the viewpoints of somatotyping and maturational age, their work permits the definition of at least comparative obesity at the various age groups and is thus a major contribution. CONSTITUTIONAL AND PHYSIOLOGIC FACTORS IN THE ETIOLOGY OF OBESITY
The complexity of the problem of the regulation of food intake is well known. 26 Any mechanism so intricate can obviously get out of order in a variety of ways. In other reviews devoted to obesity in general, it has been shown that a convenient classification of obesities can be based on the etiology of known types: one can then distinguish between genetic, traumatic and environmental factors in obesity.20 Another way of looking at obesities is to consider pathogenesis. One can then consider "regulatory" obesities, where the error is in the mechanisms, neurological and psychophysiological, which regulate food intake, and "metabolic" obesities, '" here the error is in the handling of metabolites, particularly carbohydrates and lipids. 22 Both of these types are illustrated by a number of experimental situations which have been studied in detail in the present writer's laboratory.25 Interesting suggestions that a similar distinction between the two classes is justified in man are dealt with elsewhere in this volume. Typing of obesity on the basis of anthropometric and metabolic factors is pursued actively in our laboratory. Consideration of body types and pattern of excretion of 17-ketogenic steroid may permit separation of at least one distinct form of obesity in adolescent girls from the other forms.B6 The probability that various modes of transmission of genetic factors predisposing to obesity are found in the human species as well as in animal species has been discussed at length elsewhere,24 and will not be recalled here. It is sufficient to recall that, in the Boston area, approximately 10 per cent of the children of parents of normal weight are obese at age 15, 40 per cent if one parent is obese, 80 per cent if both are obese, and that there are cogent reasons to think that these figures are due at least as much to heredity as to environment. PSYCHOLOGICAL FACTORS IN THE ETIOLOGY OF OBESITY IN CHILDHOOD
One of the ablest psychologists in the field of childhood obesity, Hilde Bruch5 • 6, 7 has classified the possibilities of associating body weight and
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adjustment in the following fashion: (1) slenderness with good adjustment; (2) slenderness with poor emotional adjustment; (3) continued obesity, usually of moderate degree, with good adjustment; and (4) continued obesity with maladjustment. In her thinking, continued obesity with good adjustment represents a "constitutional" obesity compatible with an otherwise normal personality. She assumes the obesity in this case to be due essentially to physiologic factors. Patients of this type are usually obese from childhood and stay continuously heavy, with their height and weight moving steadily in the overweight area of the growth diagram. They function adequately with this degree of obesity. Bruch believes that, in such patients, psychologic difficulties are likely to arise or to become serious only if they are forcibly reduced. The situation is quite different in what Bruch terms "reactive" obesity and in "developmental" obesity of nonconstitutional origin. She believes that in reactive obesity, overeating is a response to and a compensation for tension and frustration. In many patients, as Stunkard and Dorris40 have also emphasized, the situations leading to overeating also provoke a drastic decrease in activity. Both these factors are synergistic in causing markedly positive caloric balance. Episodes of grief or of severe depression thus coincide with drastic elevations of weight. As this type of obese patient does, in fact, tend to become depressed easily, a considerable degree of obesity can develop in a few years. Bruch considers this reactive obesity the characteristic form of psychologic obesity in adulthood and middle age. She has observed few instances of reactive obesity in childhood. Stunkard, Grace and W0lff39 emphasized that among such potentially depressed, reactive obese patients they frequently found a distinctive eating pattern which they called the "night eating syndrome." In a study conducted a few years ago in Boston, Dr. Beaudoin and P observed that an unselected group of obese women tended to distribute their calories so that proportionally they consumed more during the later hours of the day. Stunkard showed that this effect was particularly marked in obesity associated with frequent bouts of depression. In many such patients, the actual bulk of the daily calories may be consumed in the evening hours and at night, which are also the periods of the day when depression is most severe. Stunkard and Wolff showed that, in addition to this characteristic eating pattern and the decreased activity during periods of intense depression, this type of obese patient exhibits in many instances drastic changes in carbohydrate metabolism, particularly abnormally increased glucose tolerance, which coincide with the episodes of drastic weight gain. It is thus possible that physiologic changes mediate in many of these patients the psychologic trauma which indirectly leads to overeating. Interaction between psychologic and endocrine factors may explain why certain patients will tend to
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accumulate considerable excess weight during a period of grief while others faced with the same trauma may lose weight. Developmental obes£ty is described by Bruch as a common form of obesity during childhood. She believes that, in many obese children in whom the obesity is not due to purely physiologic factors, the emotional development centcrs around eating as much as they want, avoiding physical activity and social contacts, and being fat. She feels that, usually, such children are growing in a family setting in which they are used by one or the other parent (sometimes by both) as an object fulfilling his needs and compensating for failure and frustration in his own life. The child is fussed over excessively, overprotected and overfed. Generally, the mother plays the dominant role in the emotional life of such families; she indulges the obese child and keeps him close to her by constant and excessive demands. Thus, she considers that the problems of children of this type are not unlike those seen in the premorbid stage of schizophrenia. The combination of this environment and of being obese tends to promote a sense of helplessness and inadequacy which causes flight into fancy and sometimes hostility and sadism. This speaker, while admiring the diligence and care with which Hilde Bruch has collected and analyzed her material, feels that her generalizations are too broad. Psychiatrists, by the very nature of their profession, tend to see children who are psychologically outside of the more normal range seen by nutritionists, physiologists and general clinicians. Quaade, whose book on "Obese Children" is well documented, finds himself unable to confirm many of Bruch's observations. For example, to pick a striking illustration, unlike Bruch he finds in his material no more obese children among the enuretics than among normal children. He does not find in his large-scale study any confirmation for Bruch's idea that being an only child, having a peculiar family position, insufficient suckling, prolonged bottle feeding, death among the siblings, or surgical operations have any statistical relevance to the presence or absence of obesity. He feels that the fact that he examines obese children in the general population rather than psychiatric clinic patients is the cause of the discrepancy of his results with those of Bruch and of other psychiatrists. PSYCHOLOGIC ASPECTS OF BEING OBESE IN CHILDHOOD AND ADOLESCENCE
It is dangerous to underestimate the psychologic effects of the pressures of society on the obese adolescent, the obese girl in particular. The importance of these pressures and their damaging effects on the psyche of obese children were dramatically illustrated in a recent study conducted by
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Monello and Mayer27 on 100 obese girls in a weight.-reduction camp 30 and 65 nonobese controls from a typical summer camp. Three projective tests were administered in group situations: word association, sentence completion and picture description tests. The results of these tests revealed that obese girls showed personality characteristics strikingly similar to the traits of ethnic and racial minorities recognized by Gordon Allport and others as due to their status as victims of intense prejudice. One such trait is "obsessive concern": heightened sensitivity and preoccupation with one's status, exemplified in the tests by numerous word association responses concerned with such words as calories, diet, reducing, fattening, fat, heavy, overweight. Another such trait is "passivity" shown by the obese girls in their mode of response in picture description tests. "Withdrawal," the obese group's isolation and feeling of rejection by their peers, again was illustrated by the picture description responses. The obese girls also shared "acceptance of dominant values" and considered obesity-and hence their own body-as undesirable and somewhat harmful. The lack of an "ingroup," particularly the lack of family support, actually seems to expose the obese youngsters to greater tension than youngsters belonging to minority groups. The obese youngsters thus appear to be in an ambivalent situation vis a vis their own family of both greater dependence than in the case of the nonobese and at the same time greater tension. These findings may be related to those of Stunkard and Mendelson,42 who have observed obese subjects with "distorted body images" who exhibit attitudes remarkably similar to "obsessive concern" and "identification with the dominant group" noted in ethnic and racial minorities. They show an exaggerated preoccupation with weight; they judge people in terms of weight, feeling contempt for fat people and admiration for thin people, and they feel their obesity is a handicap responsible for all disappointments. Subjects displaying such attitudes had all been obese since childhood or adolescence, while suhjects failing to display such attitudes had all become obese as adults. The crucial difference between these two groups may be the extent to which punitive social pressures have affected their personalities. Children and adolescents are sensitive to such pressure and would be expected to respond more strongly than adults. It is important to keep in mind that obese youngsters, in our society, however casual and relaxed they may appear at first sight, often feel quite intensely a heavy burden of self-blame and inferiority. It is essential that the therapist not add unwittingly to this burden. Such ill-considered action can only, in the light of the finding reported above, increase such traits as passivity and withdrawal, compound the trend to physical inactivity and thus make this difficult condition even more difficult to treat. Finally, it is perhaps useful to mention that observations of patients with anorexia nervosa suggest that they present a number of characteristics
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similar to those observed in obese adolescent girls. Such patients may be characterized by what is called a "triad of denials": denial of excessive thinness, denial of hunger and denial of fatigue. The denial of excessive thinness is a consequence of a disturbance of body image which appears to be the result of panic fear of obesity: in spite of the patient's emaciation, she sees herself as hardly gaining in her unending fight against fatness. This, in turn, may well be closely akin to the obsessive concern with her appearance, typical of the obese adolescent, superimposed on a compulsive, perfectionist personality. The denial of hunger is similar to that described by Stunkard41 in many obese patients. The denial of fatigue takes place in spite of the highly ritualized, excessive exercise performed by a famished, sometimes debilitated body. When the patient is interviewed, it becomes obvious that social pressures against obesity play a major part in the etiology of the syndrome, with the trigger often provided by a chance remark of a key male figure. Thus both the behavior of the patient with anorexia nervosa as well as that of the obese youngster makes it apparent that any campaign against obesity or any treatment of the obese youngster must be performed with tact, and that the 'i:ndividual patient must be known and followed carefully so as to make sure that the medical and cosmetic advantages of weight reduction are not counterbalanced by psychological trauma. PERSISTENCE OF CHILDHOOD OBESITY
There is relatively little evidence on the course of development of obesity starting at various ages. Mullins,29 in a rctrospective study of obese patients in a London outpatient clinic, found that among 373 consecutive outpatient admissions, 26 per cent of the men and 44 per cent of the women were more than 20 per cent above "standard" weight. Approximately one-third of these patients had been obese from childhood. These patients showed a high incidence of psychological abnormalities as evaluated by clinical examination. The clinical impression also suggested that intelligence and extent of schooling were much less in the group that had been obese since childhood. While this study is of obvious interest, it must be noted that the criterion for obesity in childhood was very poor-the patients had been called "fatty." No systematic attempt was made to evaluate the possible differences in persistence associated with time of onset. Finally, the observation on the intelligence of the obese patients is at variance with the more systematic study: we could not find differences in school grades (other than physical education) between obese and nonobese high school students. A more objective evaluation of the persistence of childhood obesity
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was conducted by Abraham and Nordsieck. 1 They used height-weight records secured in children in three elementary schools in Hagerstown, Maryland, from 1937 to 1939 as their basis. These records covered 2000 boys and girls between the ages of 10 and 13. Heights were determined without shoes, and weight without shoes, sweaters and coats. Heights and weights were compared to the Baldwin-Wood averages. Fifty of the heaviest children of each sex, amounting to 5 per cent of the total, were selected as overweight. Fifty children of each sex were chosen for the "average weight" group. Only 120 of these 200 children could, however, be located at the time of the study (1960); the average age was 31 years (range 26 to 35). The results in this admittedly small group were clear-cut and showed that obesity in childhood tends to be persistent in adulthood: of the extremely overweight boys, 86 per cent were overweight as adults. Of the average weight boys, 42 per cent were overweight as adults. Among girls, 80 per cent of the extremely overweight children were overweight as adults, while only 18 per cent of the average weight children became overweight as adults. It must be noted, however, that 50 per cent of a group of moderately overweight girls were average weight or less as adults which suggests that obesity is more persistent if it is more extreme, or alternately that different syndromes are involved. A weakness of this study is that, again, it fails to differentiate between the fates of subjects in whom obesity started at various ages. Other studies, again on relatively small numbers, reported by Lloyd, Wolff and Whelen18 in Britain, by Haase and Rosenfeld13 in Germany, and by Mossberg28 in Sweden, emphasize the persistence in adulthood of most obesity cases seen in childhood, and offer suggestive evidence that this is particularly so for girls. My impression, developed in the course of studies of obesity in children over a span of many years, is that obesity which develops in the younger age groups (e.g., before 10 or after 16) has a somber prognosis for eventual weight reduction, while obesity developing just before the onset of puberty may be an exaggeration of a normal physiologic process and is often benign and self-correcting in the next few years. INACTIVITY AS A CAUSE OF OBESITY IN CHILDREN AND ADOLESCENTS
A decreased tendency for muscular activity was observed by Rony33 to be a common finding among many obese persons. He also noted that, as weight increases, the impulse for physical exertion decreases. Bruch4 rightly called attention to the relative inactivity of many obese children. Few quantitative data, however, were adduced to substantiate this statement.
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A physiologic basis for the reassessment of the possible vrimary contribution of inactivity as a cause of obesity appeared when work done in our laboratory demonstrated that, when activity is reduced to below a minimum level in experimental animals 2l and in adult men,23 a corresponding decrease in food intake does not result and obesity develops. (Actually, at very low levels of activity, in experimental animals as in men, food intake tends to increase-a phenomenon long known by farmers who "coop up" or "pen up" animals they want to fatten. This phenomenon may be interpreted in the framework of a glucostatic mechanism in the regulation of food intake, as Christophe and Mayer lO have shown that inactivity reduces glucose utilization.) It was also shown that genetically obese mice are extremely inactive, and that, conversely, exercising them (and animals with other forms of experimental obesity as well) causes spontaneous weight loss. Johnson, Burke and Mayerl7 found that the onset of excessive weight gain among obese children in the public schools of Newton and Brookline (Massachusetts) generally occurred durin~ the winter; this suggested that inactivity might be an important factor in the development of obesity. A more detailed studyl6 involving the comparison of food intake and activity schedules of 28 obese high school girls selected from this population with controls of normal weight and of the same height, age, school grades and socioeconomic status, showed that these gi.rls ate less, not more, than their normal weight controls but spent a strikingly smaller amount of time (two-thirds less) in occupations involving any amount of exercise. Similarly, Stefanik, Heald and Mayer,36 studying the food intake and amount and degree of participation of 14 obese adolescent boys and 14 paired nonobese controls at a summer camp, found both a significantly smaller intake and a smaller degree of participation in exercise among the obese boys. Stefanik et al.37 found that increased exercise made a group of adolescent girls lose weight (as well, incidentally, as lose subcutaneous fat at scapular and abdominal but not arm sites). Bullen,8 using a new technique developed for time-motion studies in industry and involving the taking of a number of photographs which are then used as a basis for the estimation of caloric expenditures based on the particular pose represented, has been able to demonstrate unequivocally that the average obese adolescent girl expends far less energy during scheduled "exercise" periods than does her nonobese counterpart. The facts that school buses and individual means of transportation are now available to almost all youngsters, that physical chores are no longer required, and that physical education programs are short and inadequate make this inactivity (which is not restricted to children) of considerable importance in the interpretation of the prevalence of obesity in our youngsters.
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The explanation of this widespread inactivity, however, is a difficult task. For one thing, just as hyperphagia admits of many different explanations, so probably, does inactivity. A priori, causes of this inactivity may be physiological or they may be psychological, or both. Furthermore, a permissive environment which no longer makes activity compulsory for survival must be present. At present, studies into causes of inactivity in youngsters are limited. Bullen et al. 9 have studied the attitudes of a group of obese adolescent girls attending a summer camp and compared them to those of a similar group of nonobese adolescent girls. The two groups completed two types of tests: a direct questionnaire administered at the beginning and end of the camp season. Very generally, the responses of the nonobese group to the questionnaire implied a family life of sociability and unity while their responses to the projective tests indicated that they had little difficulty separating from the family. In contrast, the obese group depicted a less unified family which the child was afraid to leave. The obese youngsters were aware that they were inactive, though they had no conception of the degree of their inactivity. They seemed totally unaware that they might not like physical activity (or, for that matter, that there is a relationship between inactivity and obesity). Their attitude toward eating was of interest: they were concerned about food getting but often linked it-unlike the nonobese girls-with unpleasant consequences. Even though this group of obese subjects was not generally characterized by abnormally high food intake, the obese girls said that they ate more than average and considered it the cause of their obesity. It is thus obvious that these youngsters reflect popular ideas on the subject, and that their ignorance of the state of affairs concerning their extreme inactivity is of itself a factor militating against successful treatment. Obviously, much more work is needed in this area of primary psychological factors if the etiology of the inactivity is going to be separated from the psychological effects of the obesity, which themselves tend to make the child feel rejected and hence nonparticipating in group activities and sports. An intriguing recent finding suggests a possible physiological cause (or concomitant effect) of inactivity. Wenzel, Stults and Mayer44 have found that, in an outpatient adolescent clinic population, obese youngsters had a significantly lower serum iron (with normal hemoglobin) than did nonanemic, nonobese subjects. Seltzer and Mayer34 found similar differences between larger groups of obese and nonobese adolescent girls at summer camp. Whether these low serum iron values are indicative of low myoglobin values and low values for iron-containing pigments other than hemoglobin, is not known. If they were, they might signal a situation in which, in a society tolerant of physical inactivity, exercise would be unconsciously avoided. Again, much additional research is necessary on this point before even tentative conclusions are arrived at.
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ACKNOWLEDGMENT
The author acknowledges with many thanks permission from Annual Reviews) Inc. to include excerpts from his paper published in The Annual Review of Medicine, 1963.
REFERENCES 1. Abraham, S. and Nordsieck, M.: Relationship of excess weight in children and
adults. Pub. Health. Rep. 75: 263, 1960. 2. Bayer, L. M. and Gray, H.: Plotting of a graphic record of growth for children aged from 1 to 19 years. Am. J. Dis. Child. 50: 1408, 1935. 3. Beaudoin, R. and Mayer, J.: Food intakes of obese and nonobese women. J. Am. Dietet. A. 29: 29, 1953. 4. Bruch, H.: Physiological and psychological aspects of food intake of obese children. Am. J. Dis. Child. 59: 739, 1940. 5. Bruch, H.: Fat children grown up. The J ohns Hopkins Medical and Surgical Association, Baltimore, Feb. 25, 1955. 6. Bruch, H.: Psychopathology of Hunger and Appetite in Changing Concepts of Psychoanalytic Medicine. New York, Grune & Stratton, 1956. 7. Bruch, H.: The Importance of Overweight. New York, W. W. Norton & Co., 1957. 8. Bullen, B., Reed, R. B. and Mayer, J.: Physical activity of obese and nonobese adolescent girls appraised by motion picture sampling. Am. J. Clin. Nutrition 14: 211,1964. 9. Bullen, B. A., Monello, L. F., Cohen, H. and Mayer, J.: Attitudes toward physical activity, food and family in obese and nonobese adolescent girls. Am. J. Clin. Nutrition 12: 1, 1963. 10. Christophe, J. and Mayer, J.: Effect of exercise on glucose uptake in rats and men. J. AppI. PhysioI. 13: 269, 1958. 11. Friis-Hansen, B. J., Holiday, M., Stapleton, T. and Wallace, W.: Total body water in children. Pediatrics 7: 321, 1951. 12. Garn, S. M.: Individual and group deviations from "channel wise" grid progression in girls. Child Develop. 23: 193, 1952. 13. Haase, K. E. and Rosenfeld, H. Z.: Zur fettsucht in kindesalter. Ztschr. Kinderh. 78: 1, 1956. 14. Hathaway, M. L.: Heights and weights of children and youths in the United States. U.S. Dept. Agr., Home Econ. Res. Rep. No. 2, 1957. 15. Hunt, E., Peckos, P. and Fry, P.: Factors in Human Obesity and Nutrition. Symposium Series No. 6, National Vitamin Foundation, New York, 1953. 15a. Jacobsen, G., Seltzer, C.C., Bondy, P. and Mayer, J.: Importance of body characteristics in the excretion of 17-ketosteroids and 17-kobegenic steroids in obesity. New England J. Med. 271: 651, 1964. 16. Johnson, M. L., Burke, B. S. and Mayer, J.: Relative importance of inactivity and overeating in the energy balance of obese high school girls. Am. J. Clin. Nutrition 4: 37, 1956. 17. Johnson, M. L., Burke, B. S. and Mayer, J.: Incidence and prevalence of obesity in a section of school children in the Boston area. Am. J. Clin. Nutrition 4: 231, 1956. 18. Lloyd, J. K., Wolff, O. H. and Whelen, W. S.: Childhood obesity. Brit. M. J. 5245: 145, 1961. 19. Macy, I. G. and Kelly, H. J.: Body composition in childhood. Human BioI. 28: 289,1956. 20. Mayer, J.: Genetic, traumatic and environmental factors in the etiology of obesity. PhysioI. Rev. 33: 472, 1953.
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