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Dietary restraint—A useful concept?
Appetite, 1990, 14, 129-130
Commentary Dietary
Restraint-A
Useful
Concept?
SARA E. MCCLUSKEY Department of Mental Health Sciences, St George’s Hospital Medical School
Tuschl’s (1990) paper stimulates consideration of several issues not fully dealt with in his brief review. The calorie intake of women defined as restrained eaters is not as clear as Tuschl suggests. The hypothesis that a biologically determined low caloric requirement is the primary cause of dietary restraint is taken to be supported by the relatively high former maximal BMI in restrained eaters; however, this high observed BMI may be due not to a low calorie requirement but to an intake in excess of a normal requirement. One study of undergraduate medical students showed a negative but not significant relationship between restrained eating and calorie intake (Wardle, 1980). Another study showed no difference in mean calorie intake between low and high scorers on the restraint scale (Kirkley, 1988) although, following exclusion of days when binge-eating occurred intake was significantly lower in restrained subjects. The consistent finding of biochemical indices of starvation supports the view that bulimic patients are in a relative state of deprivation for a significant amount of the time (Pirke et al., 1987). Tuschl does not emphasize the multi-factorial origins of abnormal eating behaviour. Not all women with a BMI greater than cultural norms dictate become restrained eaters. Factors other than actual body weight and the extent to which this deviates from social norms may be important in the genesis of restrained eating, familial attitudes to the importance of physical attractiveness and body weight being one example. Dissatisfaction with bodyweight may be just one expression of a pervasive lack of self esteem rooted in early personality development. The concept of poor and distorted body image has not been addressed in this paper. Research into body perception and dissatisfaction with weight has been hampered by the lack of valid instruments for their measurement. There is, however, a general consensus that bulimic women have size overestimation that is corrected following treatment (Birtchnell et al., 1985). Dolan et al. (1987) found body image distortion in non-eating disordered men and women, and a tendency for a greater degree of overestimation the greater the deviation from normal weight (in either direction). The role emotions play in the control of food intake is not discussed. Anxiety has been shown to be one factor which may result in increase in food intake by restrained eaters whilst reducing it in non-restrained eaters (Herman & Polivy, 1975). Depressed mood is accompanied by carbohydrate craving, weight gain and binge-eating in
Address reprint requests to: Dr Sara E. McCluskey, Adult Psychiatry Section, Department of Mental Health Sciences, St George’s Hospital Medical School, University of London, Cranmer Terrace, Tooting, London SW17 ORE, U.K. 01954663/90/020129 +02 $03.00/O
0 1990 Academic Press Limited
S. E. MCCLUSKEY
130
Seasonal Affective Disorder (Rosenthal et al., 1987). In her review of binge-eating, Wardle (1987) suggests that a depressed person may no longer bother to resist their appetite. An alternative explanation is that, in some restrained eaters, food intake may be increased as a means of dealing with emotional distress. It is evident that some bulimic patients attribute their distress solely to their binge-eating, inhibiting confrontation of underlying difficulties such as problems in relationships. Clinical studies of bulimic women have shown an increase in anger and depression following successful reduction in binge-eating (Lacey, 1983). Thus binge-eating may be understood in terms of the positive reinforcement produced by the temporary relief of emotional distress. The role endogenous opiates may play in this requires further exploration (Mitchell & Morley, 1987). Tuschl(l990) stresses the urgent need for the subclassification of restrained eaters. This view is supported not only by the fact that not all restrained eaters exhibit counteregulation in the laboratory, but also by the fact that bulimic and non bulimic restrained eaters differ on other parameters. Rossiter et al. (1989) found these two groups were equally dissatisfied with their weights, preoccupied by food, restrained in their eating and dissatisfied with their bodies but bulimic restrained eaters were more depressed, psychologically distressed and poorer in self esteem. It was impossible in this study to tell result from cause in the development of bulimia. A subclassification of restrained eaters may help to elucidate differences between restrained eaters who are able to maintain control and those who develop bulimia.
REFERENCES
Birtchnell, S., Lacey, J. H. & Harte, A. (1985) Body image distortion in bulimia nervosa. British Journal of Psychiatry, 147,408-412. Dolan, B., Birtchnell, S. & Lacey, J. H. (1987) Body distortion in non-eating disordered women and men. Journal of Psychosomatic Research, 31, 513-520. Herman, C. P. & Polivy, J. (1975) Anxiety, restraint and eating behaviour. Journal of Abnormal Psychology, 84, 666672. Kirkley, B. (1988) Dietary restraint, binge-eating, and dietary behaviour patterns. International Journal of Eating Disorders, 5, 771-778. Lacey, J. H. (1983) Bulimia nervosa, binge-eating, and psychogenic vomiting a controlled treatment study and long term outcome. British Medical Journal, 286, 1609-1613. Mitchell, J. & Morley, J. (1987) Endogenous opioid peptides and feeding. The psychobiology of bulimia neroosa. Pp. 101-109. Berlin: Springer. Pirke, K., Schweiger, U., Laessle, R., Fichter, M. & Wolfram, G. (1987) Metabolic and endocrine consequences of eating behaviour and food composition in bulimia. The psychobiology of bulimia neruosa. Pp. 131-143. Berlin: Springer. Rosenthal, N., Genhart, M., Sack, D., Skwerer, R. & Wehr, T. (1987) Seasonal Affective Disorder and its relevance for the understanding and treatment of bulimia. The psychobiology of bulimia nervosa. Pp. 205-225. Berlin: Springer. Rossiter, E., Wilson, G. T. & Goldstein, L. (1989) Bulimia nervosa and dietary restraint. Behavioural Research Therapy, 27, 465-468. Tnschl, R. J. (1990) From dietary restraint to binge eating: Some theoretical considerations. Appetite, 14, 105-109. Wardle, J. (1980) Dietary restraint and binge-eating. Behaoiour Analysis and Modification, 4,201. Wardle, J. (1987) Compulsive eating and dietary restraint. British Journal of Clinical Psychology, 26,47-55.
Commentary Dietary
Restraint-A
Useful
Concept?
SARA E. MCCLUSKEY Department of Mental Health Sciences, St George’s Hospital Medical School
Tuschl’s (1990) paper stimulates consideration of several issues not fully dealt with in his brief review. The calorie intake of women defined as restrained eaters is not as clear as Tuschl suggests. The hypothesis that a biologically determined low caloric requirement is the primary cause of dietary restraint is taken to be supported by the relatively high former maximal BMI in restrained eaters; however, this high observed BMI may be due not to a low calorie requirement but to an intake in excess of a normal requirement. One study of undergraduate medical students showed a negative but not significant relationship between restrained eating and calorie intake (Wardle, 1980). Another study showed no difference in mean calorie intake between low and high scorers on the restraint scale (Kirkley, 1988) although, following exclusion of days when binge-eating occurred intake was significantly lower in restrained subjects. The consistent finding of biochemical indices of starvation supports the view that bulimic patients are in a relative state of deprivation for a significant amount of the time (Pirke et al., 1987). Tuschl does not emphasize the multi-factorial origins of abnormal eating behaviour. Not all women with a BMI greater than cultural norms dictate become restrained eaters. Factors other than actual body weight and the extent to which this deviates from social norms may be important in the genesis of restrained eating, familial attitudes to the importance of physical attractiveness and body weight being one example. Dissatisfaction with bodyweight may be just one expression of a pervasive lack of self esteem rooted in early personality development. The concept of poor and distorted body image has not been addressed in this paper. Research into body perception and dissatisfaction with weight has been hampered by the lack of valid instruments for their measurement. There is, however, a general consensus that bulimic women have size overestimation that is corrected following treatment (Birtchnell et al., 1985). Dolan et al. (1987) found body image distortion in non-eating disordered men and women, and a tendency for a greater degree of overestimation the greater the deviation from normal weight (in either direction). The role emotions play in the control of food intake is not discussed. Anxiety has been shown to be one factor which may result in increase in food intake by restrained eaters whilst reducing it in non-restrained eaters (Herman & Polivy, 1975). Depressed mood is accompanied by carbohydrate craving, weight gain and binge-eating in
Address reprint requests to: Dr Sara E. McCluskey, Adult Psychiatry Section, Department of Mental Health Sciences, St George’s Hospital Medical School, University of London, Cranmer Terrace, Tooting, London SW17 ORE, U.K. 01954663/90/020129 +02 $03.00/O
0 1990 Academic Press Limited
S. E. MCCLUSKEY
130
Seasonal Affective Disorder (Rosenthal et al., 1987). In her review of binge-eating, Wardle (1987) suggests that a depressed person may no longer bother to resist their appetite. An alternative explanation is that, in some restrained eaters, food intake may be increased as a means of dealing with emotional distress. It is evident that some bulimic patients attribute their distress solely to their binge-eating, inhibiting confrontation of underlying difficulties such as problems in relationships. Clinical studies of bulimic women have shown an increase in anger and depression following successful reduction in binge-eating (Lacey, 1983). Thus binge-eating may be understood in terms of the positive reinforcement produced by the temporary relief of emotional distress. The role endogenous opiates may play in this requires further exploration (Mitchell & Morley, 1987). Tuschl(l990) stresses the urgent need for the subclassification of restrained eaters. This view is supported not only by the fact that not all restrained eaters exhibit counteregulation in the laboratory, but also by the fact that bulimic and non bulimic restrained eaters differ on other parameters. Rossiter et al. (1989) found these two groups were equally dissatisfied with their weights, preoccupied by food, restrained in their eating and dissatisfied with their bodies but bulimic restrained eaters were more depressed, psychologically distressed and poorer in self esteem. It was impossible in this study to tell result from cause in the development of bulimia. A subclassification of restrained eaters may help to elucidate differences between restrained eaters who are able to maintain control and those who develop bulimia.
REFERENCES
Birtchnell, S., Lacey, J. H. & Harte, A. (1985) Body image distortion in bulimia nervosa. British Journal of Psychiatry, 147,408-412. Dolan, B., Birtchnell, S. & Lacey, J. H. (1987) Body distortion in non-eating disordered women and men. Journal of Psychosomatic Research, 31, 513-520. Herman, C. P. & Polivy, J. (1975) Anxiety, restraint and eating behaviour. Journal of Abnormal Psychology, 84, 666672. Kirkley, B. (1988) Dietary restraint, binge-eating, and dietary behaviour patterns. International Journal of Eating Disorders, 5, 771-778. Lacey, J. H. (1983) Bulimia nervosa, binge-eating, and psychogenic vomiting a controlled treatment study and long term outcome. British Medical Journal, 286, 1609-1613. Mitchell, J. & Morley, J. (1987) Endogenous opioid peptides and feeding. The psychobiology of bulimia neroosa. Pp. 101-109. Berlin: Springer. Pirke, K., Schweiger, U., Laessle, R., Fichter, M. & Wolfram, G. (1987) Metabolic and endocrine consequences of eating behaviour and food composition in bulimia. The psychobiology of bulimia neruosa. Pp. 131-143. Berlin: Springer. Rosenthal, N., Genhart, M., Sack, D., Skwerer, R. & Wehr, T. (1987) Seasonal Affective Disorder and its relevance for the understanding and treatment of bulimia. The psychobiology of bulimia nervosa. Pp. 205-225. Berlin: Springer. Rossiter, E., Wilson, G. T. & Goldstein, L. (1989) Bulimia nervosa and dietary restraint. Behavioural Research Therapy, 27, 465-468. Tnschl, R. J. (1990) From dietary restraint to binge eating: Some theoretical considerations. Appetite, 14, 105-109. Wardle, J. (1980) Dietary restraint and binge-eating. Behaoiour Analysis and Modification, 4,201. Wardle, J. (1987) Compulsive eating and dietary restraint. British Journal of Clinical Psychology, 26,47-55.