Appetite, 1990, 14, 137-141
Commentary Some Restrictions on Dietary Restraint JOACHIM WESTENHOEFER, NORBERT MAUS
VOLKER PUDEL and
Department of Psychiatry, University of Goettingen
Tuschl(l990) analyses mediating mechanisms between dietary restraint and binge eating. Two simultaneous processes are described: restrained eating enhancing the attractiveness of food, and restrained eating extinguishing the learned components of satiation. There is little doubt as to the involvement of these processes in the development of binge eating. However, the relative contribution of these processes to the development of binge eating still remains unclear. With regard to binge eating, as seen in patients with bulimia nervosa, we raise three points. (1) Is there only a quantitative difference or a qualitative change between casual oversized meals, hyperphagic reactions, e.g. under stress, and clinically relevant eating binges? (2) Why do some restrained eaters develop symptoms of binge eating, whereas some do not, and some even manage to be successful dieters? (3) Is the concept of restrained eating, although it has been useful for more than a decade, too global to explain the different degrees of control and disinhibition of food intake?
QUANTITATIVE DIFFERENCEOR QUALITATIVE CHANGE?
The impairment of the satiation process, resulting from the extinction of conditioned satiety cues, may clearly lead to overeating, once cognitive control of eating has broken down. The enhanced attractiveness of palatable food may also give rise to oversized meals. However, the interpretation of eating binges as an equivalent or mere extension of overeating or oversized meals seems at least problematic. As Cooper & Fairburn (1987) point out, binge eating “does not have a generally accepted specific meaning. It certainly cannot be assumed that people who report eating in binges on such (self-report) questionnaires necessarily experience eating episodes of the type seen among patients with anorexia nervosa or bulimia nervosa”. The stated mechanisms may explain the phenomenon of overeating under conditions of absence of cognitive control. Up to now, there is no empirical evidence that these mechanisms might override cognitive control. A feeling of lack of control over eating behavior during the eating binges is characteristic in bulimia nervosa (APA, 1987). These patients are not able to stop eating although they are quite aware of the fact that they are overeating. Thus we would like to know which mechanisms yield the disinhibition phenomenon, the breakdown of cognitive control.
Addressreprintrequests to: Dr V. Pudel, Department of Psychiatry, University of Goettingen, vonSiebold-Str. 5, D-3400 Goettingen, F.R.G. 0195-6663/90/020137+05 SO34IO/O
0 1990 Academic Press Limited
138
J. WFSTENHOEFER ET AL.
There is some evidence that emotional states such as frustration, boredom and anger are promoting factors for eating binges in bulimia nervosa patients (Paul & Pudel, 1985). In connection with poorly developed problem-solving and assertion skills (Wolchik et al., 1986; Westenhoefer et al., 1987), this suggests the possible role of binge eating as an inadequate coping mechanism. The purging behavior of bulimic patients might also be of central importance in the maintenance of binge eating (Rosen & Leitenberg, 1988): Bulimia nervosa patients would rarely binge-eat, if they did not plan to vomit afterwards. Thus it seems to us that binge eating is not merely overeating, and there seem to exist several mediating and maintaining mechanisms which have not been mentioned by Tuschl (1990).
RESTRAINEDEATING AND THE DISINHIFSITION OF CONTROL
As Tuschl points out, there is some evidence that a subgroup of restrained eaters manages to be successful dieters without developing disturbances in eating behavior. In a representative sample of the female population of West Germany (n = lOOO),we found that a far lower percentage of women with a more permanent dieting behavior experience problems in eating behavior than women with intermittent dieting behavior (Westenhoefer & Pudel, 1989; see Table 1). The most frequently reported problems included exaggerated appetite for sweets, binge eating, and eating under conditions of stress. Obviously, intermittent dieting may be one of the factors giving rise to disturbances of eating behavior. However, the data show that about half of the women, who are permamently dieting, may do so without problems. This phenomenon has led us to look at our data in a two-dimensional way. Using the Three Factor Eating Questionaire (TFEQ, Stunkard & Messick, 1985), we found fairly low correlations between the restraint and disinhibition factor in several studies (Pudel & Westenhoefer, 1989 a). Even in high restraint subgroups we found substantial portions of subjects with very low as well as very high scores on the disinhibition scale. In a study of over 35,000 readers of a women’s magazine, the actual body weight (body mass index, BMI) depended on both restraint and disinhibition (Westenhoefer & Pudel, 1989; see Figure 1).This finding is in contrast to the results of Laessle et al. (1989) who reported that actual weight is higher in restrained eaters. Their high restrained subjects show significantly higher disinhibition scores than low restrained subjects, so their finding might be due to some correlation of the restraint and disinhibition factors TABLE 1
Slimming diets and problems in eating behavior. Results froma representative sample of 1000 women How often did you
diet until now?
Percentage of women reporting problems in eating behavior
Never l-3 times More than 3 times Regularly Permanently
27.0 80.6 96.6 91.8 57.9
FROM DIETARY RESTRAINT TO BINGE EATING
139
28 27 26 25 ih disinhibition
24 23 22 ow dislnhibltion
21 high
low restraint
restraint
FIGURE 1. Mean body mass index (BMI) in several subgroups with varying restraint and disinhibition. Results from a study of 35,000 readers of a women’s magazine.
/’ //
disinhibition
low restraint
high
restraint
FIGURE2. Mean daily energy intake (kcabday) in several subgroups with varying restraint and disinhibition. Results from a study with 46,769 participants at the beginning of a weightreduction program.
140
J. WFLWENHOEFERET AL.
in their sample. We also found a two-way influence of restraint and disinhibition on energy intake (Figure 2) and nutrient composition in a study of 46,769 subjects at the beginning of a weight reduction program (Pudel & Westenhoefer, 1989 b). These data emphasize that restrained eaters are far from being a homogeneous group with regard to their actual eating behavior and the consequences thereof.
Is THE CONCEPT OF RESTRAINTTOO GLOBAL? The findings reported above indicated that we have to look on restrained eating in a more sophisticated way. While there is some evidence that dietary restraint does not necessarily imply disturbances in eating behavior due to the disinhibition of control, we are far from understanding why disinhibition of control develops in a substantial portion of restrained eaters, but does not develop in others. Restrained eating is defined as the intention to restrict food intake, and available data shows that restrained eaters actually do restrict food intake. However, there might be several behavioral strategies to do so. These strategies might vary in the restriction of the amount and selection of “slimming” foods, in their effectiveness in establishing restrained eating as long-term behavior, and in their potential of promoting disturbances of intake regulation. One strategy, often used by bulimic patients, is to reduce the complexity of eating to the simple question: “to eat or not to eat?“. If they decide to eat, they restrict food intake exclusively to a small variety of “good food”. This dichotomized thinking might yield rigid control of eating behavior leaving narrow margins and leading to frustration. This rigid control should be labeled as “pseudo-control”, because it lacks adequately calibrated self-regulation. On the other hand, a more flexible control of eating behavior may exist which adequately takes into account situational components and personal preferences. These considerations show that the concept of restraint should be refined, because adequate control as well as pseudo-control and several behavioral strategies in between are subsumed under the label of restrained eating. We advance the following hypothesis: there are behavioral strategies, which were unspecifically labeled as “restraint”, with a lower or higher risk of disturbances in eating behavior. Thus restrained eating is, in accordance with Tuschl(1990), a necessary condition but not at all a sufficient condition for the development of eating disorders.
REFERENCES
American Psychiatric Association (1987)Diagnostic and statistical manual ofmental disorders. (3rd Edn) Washington, DC. Cooper, Z. & Fairbum, C. (1987) The Eating Disorder Examination: A semi-structured interview for the assessment of the specific psychopathology of eating disorders. International Journal of Eating Disorders, 6, 1-8. Laessle, R. G. Tuschl, R. J., Kotthaus, B. C. & Pirke, K. M. (1989) Behavioral and biological correlates of dietary restraint in normal life. Appetite, 12, 83-94. Paul, T. & Pudel, V. (1985) Bulimia nervosa: Suchtartiges EDverhalten als Folge von Diltabusus? Erniihrungsumschau, 32, 74-79.
Pudel, V. 8z Westenhoefer, J. (1989 a) Fragebogen zum Ejuerhulten.
Gattingen:
Hogrefe.
FROM DIETARY RWI-RAINT TO BINGE EATING
141
Pudel, V. & Westenhoefer, J. (1989 b) Vier-Jahreszeiten-Kur. Eine rechnergestictzte Strategic zur Beeinjlussung des Erniihrungsverhaltens und zur Gewichtsreduktion. Forschungsbericht zur Entwicklung und Evaluation. Giittingen: Emlhrungspsychologische Forschungsstelle der Universitat. Rosen, J. C. & Leitenberg, H. (1988) The anxiety model of bulimia nervosa and treatment with exposure plus response prevention. In K. M. Pirke, W. Vandereycken & D. Ploog (Eds.) The Psychobiology of Bulimia Nervosa. Pp. 146-151. Berlin: Springer. Stunkard, A. J. & Messick, S. (1985) The three-factor eating questionnaire to measure dietary restraint, disinhibition and hunger. Journal of Psychosomatic Research, 29, 71-83. Tuschl, R. J. (1990) From dietary restraint to binge eating: some theoretical considerations. Appetite, 14, 105-109.
Westenhoefer, J., Paul, T. & Pudel, V. (1987) Zur Selbtkontrollfahigkeit
bulimischer Patienten.
Verhaltensmodijikation und Verhaltensmedizin, 8, 314-333.
Westenhoefer, J. & Pudel, V. (1989) Verhaltensmedizinische fiberlegungen zur Entstehung und Behandlung von EBstiirungen..In R. Wahl & M. Hautzinger (Eds.) Verhaltensmedizin. Pp. 149-162. Kiiln: Deutscher Arzte Verlag. Wolchik, S. A., Weiss, L. & Katzman, M. A. (1986) An empirically validated, short-term psychoeducational treatment program for bulimia. Znternutional Journal of Eating Disorders, 5, 21-34.
Commentary Some Restrictions on Dietary Restraint JOACHIM WESTENHOEFER, NORBERT MAUS
VOLKER PUDEL and
Department of Psychiatry, University of Goettingen
Tuschl(l990) analyses mediating mechanisms between dietary restraint and binge eating. Two simultaneous processes are described: restrained eating enhancing the attractiveness of food, and restrained eating extinguishing the learned components of satiation. There is little doubt as to the involvement of these processes in the development of binge eating. However, the relative contribution of these processes to the development of binge eating still remains unclear. With regard to binge eating, as seen in patients with bulimia nervosa, we raise three points. (1) Is there only a quantitative difference or a qualitative change between casual oversized meals, hyperphagic reactions, e.g. under stress, and clinically relevant eating binges? (2) Why do some restrained eaters develop symptoms of binge eating, whereas some do not, and some even manage to be successful dieters? (3) Is the concept of restrained eating, although it has been useful for more than a decade, too global to explain the different degrees of control and disinhibition of food intake?
QUANTITATIVE DIFFERENCEOR QUALITATIVE CHANGE?
The impairment of the satiation process, resulting from the extinction of conditioned satiety cues, may clearly lead to overeating, once cognitive control of eating has broken down. The enhanced attractiveness of palatable food may also give rise to oversized meals. However, the interpretation of eating binges as an equivalent or mere extension of overeating or oversized meals seems at least problematic. As Cooper & Fairburn (1987) point out, binge eating “does not have a generally accepted specific meaning. It certainly cannot be assumed that people who report eating in binges on such (self-report) questionnaires necessarily experience eating episodes of the type seen among patients with anorexia nervosa or bulimia nervosa”. The stated mechanisms may explain the phenomenon of overeating under conditions of absence of cognitive control. Up to now, there is no empirical evidence that these mechanisms might override cognitive control. A feeling of lack of control over eating behavior during the eating binges is characteristic in bulimia nervosa (APA, 1987). These patients are not able to stop eating although they are quite aware of the fact that they are overeating. Thus we would like to know which mechanisms yield the disinhibition phenomenon, the breakdown of cognitive control.
Addressreprintrequests to: Dr V. Pudel, Department of Psychiatry, University of Goettingen, vonSiebold-Str. 5, D-3400 Goettingen, F.R.G. 0195-6663/90/020137+05 SO34IO/O
0 1990 Academic Press Limited
138
J. WFSTENHOEFER ET AL.
There is some evidence that emotional states such as frustration, boredom and anger are promoting factors for eating binges in bulimia nervosa patients (Paul & Pudel, 1985). In connection with poorly developed problem-solving and assertion skills (Wolchik et al., 1986; Westenhoefer et al., 1987), this suggests the possible role of binge eating as an inadequate coping mechanism. The purging behavior of bulimic patients might also be of central importance in the maintenance of binge eating (Rosen & Leitenberg, 1988): Bulimia nervosa patients would rarely binge-eat, if they did not plan to vomit afterwards. Thus it seems to us that binge eating is not merely overeating, and there seem to exist several mediating and maintaining mechanisms which have not been mentioned by Tuschl (1990).
RESTRAINEDEATING AND THE DISINHIFSITION OF CONTROL
As Tuschl points out, there is some evidence that a subgroup of restrained eaters manages to be successful dieters without developing disturbances in eating behavior. In a representative sample of the female population of West Germany (n = lOOO),we found that a far lower percentage of women with a more permanent dieting behavior experience problems in eating behavior than women with intermittent dieting behavior (Westenhoefer & Pudel, 1989; see Table 1). The most frequently reported problems included exaggerated appetite for sweets, binge eating, and eating under conditions of stress. Obviously, intermittent dieting may be one of the factors giving rise to disturbances of eating behavior. However, the data show that about half of the women, who are permamently dieting, may do so without problems. This phenomenon has led us to look at our data in a two-dimensional way. Using the Three Factor Eating Questionaire (TFEQ, Stunkard & Messick, 1985), we found fairly low correlations between the restraint and disinhibition factor in several studies (Pudel & Westenhoefer, 1989 a). Even in high restraint subgroups we found substantial portions of subjects with very low as well as very high scores on the disinhibition scale. In a study of over 35,000 readers of a women’s magazine, the actual body weight (body mass index, BMI) depended on both restraint and disinhibition (Westenhoefer & Pudel, 1989; see Figure 1).This finding is in contrast to the results of Laessle et al. (1989) who reported that actual weight is higher in restrained eaters. Their high restrained subjects show significantly higher disinhibition scores than low restrained subjects, so their finding might be due to some correlation of the restraint and disinhibition factors TABLE 1
Slimming diets and problems in eating behavior. Results froma representative sample of 1000 women How often did you
diet until now?
Percentage of women reporting problems in eating behavior
Never l-3 times More than 3 times Regularly Permanently
27.0 80.6 96.6 91.8 57.9
FROM DIETARY RESTRAINT TO BINGE EATING
139
28 27 26 25 ih disinhibition
24 23 22 ow dislnhibltion
21 high
low restraint
restraint
FIGURE 1. Mean body mass index (BMI) in several subgroups with varying restraint and disinhibition. Results from a study of 35,000 readers of a women’s magazine.
/’ //
disinhibition
low restraint
high
restraint
FIGURE2. Mean daily energy intake (kcabday) in several subgroups with varying restraint and disinhibition. Results from a study with 46,769 participants at the beginning of a weightreduction program.
140
J. WFLWENHOEFERET AL.
in their sample. We also found a two-way influence of restraint and disinhibition on energy intake (Figure 2) and nutrient composition in a study of 46,769 subjects at the beginning of a weight reduction program (Pudel & Westenhoefer, 1989 b). These data emphasize that restrained eaters are far from being a homogeneous group with regard to their actual eating behavior and the consequences thereof.
Is THE CONCEPT OF RESTRAINTTOO GLOBAL? The findings reported above indicated that we have to look on restrained eating in a more sophisticated way. While there is some evidence that dietary restraint does not necessarily imply disturbances in eating behavior due to the disinhibition of control, we are far from understanding why disinhibition of control develops in a substantial portion of restrained eaters, but does not develop in others. Restrained eating is defined as the intention to restrict food intake, and available data shows that restrained eaters actually do restrict food intake. However, there might be several behavioral strategies to do so. These strategies might vary in the restriction of the amount and selection of “slimming” foods, in their effectiveness in establishing restrained eating as long-term behavior, and in their potential of promoting disturbances of intake regulation. One strategy, often used by bulimic patients, is to reduce the complexity of eating to the simple question: “to eat or not to eat?“. If they decide to eat, they restrict food intake exclusively to a small variety of “good food”. This dichotomized thinking might yield rigid control of eating behavior leaving narrow margins and leading to frustration. This rigid control should be labeled as “pseudo-control”, because it lacks adequately calibrated self-regulation. On the other hand, a more flexible control of eating behavior may exist which adequately takes into account situational components and personal preferences. These considerations show that the concept of restraint should be refined, because adequate control as well as pseudo-control and several behavioral strategies in between are subsumed under the label of restrained eating. We advance the following hypothesis: there are behavioral strategies, which were unspecifically labeled as “restraint”, with a lower or higher risk of disturbances in eating behavior. Thus restrained eating is, in accordance with Tuschl(1990), a necessary condition but not at all a sufficient condition for the development of eating disorders.
REFERENCES
American Psychiatric Association (1987)Diagnostic and statistical manual ofmental disorders. (3rd Edn) Washington, DC. Cooper, Z. & Fairbum, C. (1987) The Eating Disorder Examination: A semi-structured interview for the assessment of the specific psychopathology of eating disorders. International Journal of Eating Disorders, 6, 1-8. Laessle, R. G. Tuschl, R. J., Kotthaus, B. C. & Pirke, K. M. (1989) Behavioral and biological correlates of dietary restraint in normal life. Appetite, 12, 83-94. Paul, T. & Pudel, V. (1985) Bulimia nervosa: Suchtartiges EDverhalten als Folge von Diltabusus? Erniihrungsumschau, 32, 74-79.
Pudel, V. 8z Westenhoefer, J. (1989 a) Fragebogen zum Ejuerhulten.
Gattingen:
Hogrefe.
FROM DIETARY RWI-RAINT TO BINGE EATING
141
Pudel, V. & Westenhoefer, J. (1989 b) Vier-Jahreszeiten-Kur. Eine rechnergestictzte Strategic zur Beeinjlussung des Erniihrungsverhaltens und zur Gewichtsreduktion. Forschungsbericht zur Entwicklung und Evaluation. Giittingen: Emlhrungspsychologische Forschungsstelle der Universitat. Rosen, J. C. & Leitenberg, H. (1988) The anxiety model of bulimia nervosa and treatment with exposure plus response prevention. In K. M. Pirke, W. Vandereycken & D. Ploog (Eds.) The Psychobiology of Bulimia Nervosa. Pp. 146-151. Berlin: Springer. Stunkard, A. J. & Messick, S. (1985) The three-factor eating questionnaire to measure dietary restraint, disinhibition and hunger. Journal of Psychosomatic Research, 29, 71-83. Tuschl, R. J. (1990) From dietary restraint to binge eating: some theoretical considerations. Appetite, 14, 105-109.
Westenhoefer, J., Paul, T. & Pudel, V. (1987) Zur Selbtkontrollfahigkeit
bulimischer Patienten.
Verhaltensmodijikation und Verhaltensmedizin, 8, 314-333.
Westenhoefer, J. & Pudel, V. (1989) Verhaltensmedizinische fiberlegungen zur Entstehung und Behandlung von EBstiirungen..In R. Wahl & M. Hautzinger (Eds.) Verhaltensmedizin. Pp. 149-162. Kiiln: Deutscher Arzte Verlag. Wolchik, S. A., Weiss, L. & Katzman, M. A. (1986) An empirically validated, short-term psychoeducational treatment program for bulimia. Znternutional Journal of Eating Disorders, 5, 21-34.
