Body Dissatisfaction and Binge Eating in Obese Women: The Role of Restraint and Depression

Transcription

1 Body Dissatisfaction and Binge Eating in Obese Women: The Role of Restraint and Depression Jane Wardle, Jo Waller, and Lorna Rapoport Abstract WARDLE, JANE, JO WALLER, AND LORNA RAPOPORT. Body dissatisfaction and binge eating in obese women: the role of restraint and depression. Obes Res. 2001;9: Objective: This study examined the association between body dissatisfaction and binge eating, and the mediating role of restraint and depression among obese women. Research Methods and Procedures: Participants were obese women taking part in a cognitive-behavioral treatment program who completed self-report measures at baseline (n 89) and post-treatment follow-up (n 69). Results: At baseline, body dissatisfaction was strongly correlated with binge eating score. This was partly a direct effect and partly mediated by depression. No mediating effect of restraint was observed. Over the treatment period, a reduction in body dissatisfaction was associated with a reduction in binge-eating score. As in the cross-sectional data, there was evidence for mediation by change in depression with the greatest improvement in binge eating among those who became more restrained and less depressed. Discussion: These results suggest that it would be valuable to address psychological well-being, and especially body image, as part of the management of binge-eating behavior in obesity. Key words: body image, depression, eating, women, restraint Introduction Between 20% and 50% of people presenting for obesity treatment report moderate or severe binge-eating problems (1). This high prevalence has led to an upsurge of interest in Submitted for publication May 22, Accepted for publication in final form September 25, ICRF Health Behaviour Unit, Department of Epidemiology and Public Health, University College London, London, United Kingdom. Address correspondence to Dr. Jane Wardle, Department of Epidemiology and Public Health, University College London, London WC1E 6BT, UK. j.wardle@ucl.ac.uk Copyright 2001 NAASO binge eating among the obese and the formulation of a diagnostic category in the Diagnostic and Statistical Manual of Mental Disorders, IV (2), distinct from bulimia nervosa, of binge-eating disorder (BED). Prevalence of BED has been estimated at 30% for people attending obesity treatment and between 2% and 3% in community samples of obese people (3,4). A number of studies have investigated characteristics associated with binge eating among the obese. Striegel- Moore et al. (5) found that women with BED were more depressed, had lower self-esteem, and had greater body dissatisfaction than nonbinge-eating obese controls. They also found that people with subthreshold BED and overeaters tended to show higher levels of these traits than the nonbinge-eating control group, indicating a continuum of increasing risk with increasing binge eating. Similar positive correlations between binge eating and psychopathology have been found in other clinical populations (3,6 8). Estimates of the precise prevalence of psychopathology among binge-eaters vary according to whether samples are drawn from the community or from individuals seeking treatment. In a community sample, lifetime prevalence rates for major depression and any Axis I or Axis II disorders were higher in BED women relative to controls, but lower than clinical studies have suggested (9). Therefore, it seems that there is an established relationship between binge eating and emotional difficulties, particularly depression. This has been found to be independent of body mass index (BMI) and has been hypothesized to account for observed associations between obesity and depression (10). There is also a robust association between binge eating and body dissatisfaction (11), as well as suggestions that self-esteem and self-efficacy might vary with levels of binge eating among the obese (12). There is an extensive related literature on bulimic behavior in the nonclinical population that consistently shows associations among body dissatisfaction, dietary restraint, and eating problems such as emotional eating and binge eating (13 18). The underlying process has been widely assumed to be one in which body dissatisfaction causes 778 OBESITY RESEARCH Vol. 9 No. 12 December 2001

2 dietary restraint, which in turn causes susceptibility to loss of control over eating (14,19). Only relatively recently have there been direct attempts to test the hypothesis that restraint mediates the association between body dissatisfaction and binge eating. In a sample of women university students, Ricciardelli et al. (20) measured body dissatisfaction, restrained eating, and binge eating and found the usual strong associations among the variables. They then tested the role of restraint in mediating the association between body dissatisfaction and binge eating using hierarchical regression analysis. Body dissatisfaction was entered into the regression model first, explaining 40% of the variance in binge eating. Restraint was then added to the model, but it failed to reduce the variance attributable to body dissatisfaction, indicating that it was unlikely to be mediating the effect of body dissatisfaction. An alternative view of the body dissatisfaction binge eating relationship gives greater prominence to the role of negative affect or depression. Depression has long been viewed as a disinhibitory factor in binge-eating behavior. In their comprehensive review of the literature on stress and eating, Greeno and Wing (21) concluded that stress (including depression) was associated with increased food intake in restrained eaters, compared with either no affect or decreased intake in unrestrained eaters. Mood has also been shown to be lower before binge episodes than at randomly chosen moments in the day in obese binge-eaters (22). These observations suggest that binge-eating problems might be at their worst among depressed, highly restrained eaters, as proposed in the dual pathway model of bulimic behavior (15,23). According to the dual pathway model of Stice et al. (23), body dissatisfaction can induce both restraint and depression, either of which can lead to binge eating. Restraint acts through counter-regulatory pathways, and depression acts either through increasing disinhibition of restraint or because some individuals might use binge eating to regulate affect. Shepherd and Ricciardelli (24) tested the mediating role of restraint and depression in combination, in a student population. They found that body dissatisfaction explained less of the variance in binge eating when restraint and depression scores were added to their regression model than it had explained when entered alone, suggesting that the effect of body dissatisfaction was partially mediated by one or both of these variables. Likewise, Stice et al. (25) found that negative affect and dietary restraint mediated the effects of perceived pressure to be thin, body mass, thin ideal internalization, and body dissatisfaction on subsequent bulimic symptomatology among a normal-weight adolescent population. Shepherd and Ricciardelli (24) noted (though did not test) the possibility that depression might interact with restraint, such that high levels of depression would only be associated with overeating in restrained eaters. This was confirmed in a recent study in a nonclinical adolescent population (23), which found that in the low-depression group, binge eating was scarcely any higher in highly restrained than in unrestrained eaters, whereas in the highdepression group, restraint was strongly associated with binge eating. The apparent interaction between restraint and depression raises the possibility that restraint in the obese population might have adverse effects only among those who have high depression. Although the dual pathway model has not been tested in obese binge-eaters, several studies have investigated the role of dietary restraint in the etiology of BED. These have tended to focus on the time sequence of the first binge and first dieting episodes (26 28). Grilo and Masheb (26) concluded that in a substantial proportion of patients with BED, the first binge precedes the first diet, casting doubt on the notion that binge eating is a simple consequence of restraint, as some authors have suggested (29,30). There is also evidence that obese binge-eaters do not generally have higher levels of restraint than obese nonbinge-eaters (3,7,31 34), which again argues for a more complex etiological mechanism leading to binge eating among the obese. Restraint may play a significant role in the etiology of BED for some individuals but not for others. Stice and Agras (35) suggested that bulimic women can be subtyped according to the extent to which they fit dietary restraint or negative affect profiles. The same may be true for those with BED. Given the associations among body dissatisfaction, depression, and binge eating, and the ambiguous nature of the relationship between restraint and binge eating among the obese, the dual pathway model may be useful in further understanding the relationship between body dissatisfaction and binge eating in clinical obese populations. Therefore, we investigated the associations among body dissatisfaction, restraint, depressed mood, and binge-eating behavior in a clinical sample of obese women participating in a cognitive-behavioral therapy (CBT) program. Women in the study were not BED patients but were assessed for binge-eating behavior. The use of a longitudinal design allowed more rigorous testing of the mediation effects than is possible with cross-sectional data. The specific aims were to consider restraint and depressed mood as potential mediators of the established association between body dissatisfaction and binge eating and to test the hypothesis that restraint and depressed mood interact in their association with binge eating, i.e., that restraint is more strongly associated with binge eating in depressed obese people than in obese people who are not depressed. Two sets of analyses were carried out. The first set used data from the baseline (pretreatment) assessment to examine cross-sectional associations among body satisfaction, restraint, depressed mood, and binge-eating behavior. The second set of analyses examined associations among changes in body satisfaction, restraint, and depressed mood over the treatment period, and changes in binge eating. OBESITY RESEARCH Vol. 9 No. 12 December

3 These longitudinal analyses permitted a stronger test of any apparent causal associations that emerged cross-sectionally. Research Methods and Procedures Participants Participants were overweight and obese women taking part in one of two CBT programs for weight control. They were randomly allocated either to a standard CBT (S-CBT), the primary aim of which was weight loss, or to modified CBT (M-CBT), which placed less emphasis on short-term weight loss and more on permanent lifestyle change. The two programs are described in detail elsewhere (36). S-CBT participants lost more weight in the short-term, but there were no post-treatment differences in binge eating, body satisfaction, depression, or restraint (36), so data from the two groups are combined for the present analyses. Inclusion criteria for the program were as follows: over 18 years of age and having a selfreported BMI of at least 28 kg/m 2. Women who were pregnant or lactating or who had serious medical or psychiatric conditions were excluded. Of the women attending the baseline assessment, 4.5% reported having type 2 diabetes and 20% reported taking medication for hypertension or angina. All participants were approved by their general practitioner (primary physician) as being suitable to take part in a weight-loss program. Ninety-six women were offered assessment for suitability for the program, 89 attended the baseline assessment session, 75 began treatment, and 69 attended the end of treatment assessment. Data from the 89 women who attended the baseline assessment were used for the cross-sectional analyses. Longitudinal analyses used data from the 69 women who followed the 10-week treatment program and who attended the post-treatment assessment 12 weeks after the baseline assessment. Measures Binge-eating behavior was assessed with the Binge Eating Scale (BES) (37). This is a 16-item assessment of binge-eating behavior and feelings surrounding binging episodes. Scores can range from 0 to 64, with a score of 27 or above being indicative of meeting the Diagnostic and Statistical Manual of Mental Disorders, III criteria for bulimia (32). Scores in obese clinical samples have averaged 17, with 10% scoring above the clinical cutoff (38). Dietary restraint was assessed using the restrained eating scale of the Three Factor Eating Questionnaire (TFEQ-R) (39). This is a 10-item scale that has been shown to discriminate between dieters and unrestrained eaters. The mean TFEQ restraint score in a sample of obese participants in a weight gain-prevention program was 8 (31); higher scores indicating more restrained eating. Body satisfaction was measured using the Body Satisfaction Scale (36), which averages degree of satisfaction with waist, bust, hips, thighs, calves, ankles, upper arms, lower arms, wrists, face, and whole body. Each item is rated on a 6-point Likert scale from extremely satisfied to extremely unsatisfied, with a possible total score range from 11 to 66. The scale has high internal reliability ( 0.91) and is significantly correlated with the Body Image Avoidance Questionnaire (40) (r 0.31; p 0.01 in this sample). The Body Image Avoidance Questionnaire is a widely used and well-validated measure of behaviors associated with poor body image. Depressed mood was assessed with the Beck Depression Inventory (BDI) (41). This is a 21-item scale and scores can range from 0 to 84. For the purposes of this study, the item relating to weight loss was excluded from the calculation of the total score. Participants were weighed and measured, and BMI was calculated using Quetlet s index (weight in kilograms divided by height in square meters). Demographic items included age, ethnicity, marital status, work status, housing tenure, and level of education, which were assessed with single questions. Statistical Analysis Analyses of baseline data were carried out first with bivariate correlations and partial correlations, and then with a series of regression models investigating the amount of variance in binge-eating scores explained by each of the predictor variables in turn. Analyses of the longitudinal data followed the same pattern, first examining associations between change scores and then testing a systematic sequence of regression models. One of the aims was to establish whether restraint or negative affect mediated the association between body dissatisfaction and binge eating. To support the hypothesis that the relationship between body dissatisfaction and binge eating is mediated by restraint and depression, the following conditions must hold (42): body dissatisfaction must be associated with restraint and depression, restraint and depression must be associated with binge eating, and the association between body dissatisfaction and binge eating must be completely or substantially reduced when controlling for restraint and depression. Results The women who participated in the program were predominantly white (72%), married (65%), and working (59%). Twenty percent were educated to university degree level. Their mean age was 47 years ( 11 years) and their mean BMI was 36 kg/m 2 ( 6 kg/m 2 ), ranging from 27 to 63 kg/m 2. Weight and psychological variables are shown in Table 1. Baseline scores on the psychological variables were normally distributed, although BDI (depression) scores were skewed slightly toward the lower end of the scale, 780 OBESITY RESEARCH Vol. 9 No. 12 December 2001

4 Table 1. Pearson correlations, means, and SDs from the cross-sectional data (n 89) Binge eating Body dissatisfaction Restraint Depression BMI Mean SD Binge eating* Body dissatisfaction 0.41, p Restraint 0.11, p , p Depression 0.53, p , p , p BMI 0.03, p , p , p , p Age 0.28, p , p , p , p , p * Gormally BES. Restrained eating scale of TFEQ. BDI. as would be expected for a nonclinical group. The average BES score (15.7) and the proportion of the sample scoring over 27 (12.5%) was similar to other studies (38). The mean restraint score (9.2) was also comparable to other studies (26,31). Depression was, on average, somewhat higher (10.5) than has been reported in other obese samples (31,38). Cross-Sectional Analyses Bivariate correlations were used to investigate the strength of the relationships among variables in the baseline assessment (Table 1). Age was significantly (negatively) associated with binge-eating behavior and depressed mood, and BMI was associated with body dissatisfaction, so age and BMI were controlled for, as appropriate, in the subsequent analyses. As predicted, binge eating was associated with body dissatisfaction (r 0.41) and the association remained equally significant after controlling for age and BMI (r 0.43; p 0.001). Contrary to our expectation, there was no significant correlation between binge eating and dietary restraint or between dietary restraint and body dissatisfaction, indicating that restraint did not play a simple mediating role between body image and binge eating in this sample. Depressed mood was associated both with binge eating (r 0.53) and body dissatisfaction (r 0.37), which was consistent with it partly mediating the association between these two variables. Regression analyses were used to investigate the possibility that depressed mood mediated the association between body dissatisfaction and binge eating (Table 2). In the simplest model (Model 1), age and body dissatisfaction explain 21% of the variance in binge-eating score. Adding depression (Model 2) had a substantial effect, increasing the overall variance explained to 34%, while reducing the unique amount of variance explained by body dissatisfaction from 16% to 6% (a 63% reduction). This suggests that as well as having a direct effect on binge eating, depression partially mediates the body dissatisfaction effect in obese Table 2. Associations between the BES score and body dissatisfaction and depression in the baseline data (n 89) weights and squared semi-partial correlations Model 1 Model 2 Model 3 sr 2 sr 2 sr 2 Age 0.25* Body dissatisfaction Depression (BDI) Adjusted R * p p OBESITY RESEARCH Vol. 9 No. 12 December

5 Table 3. Body dissatisfaction, restraint, depression, and the interaction between restraint and depression, as predictors of binge eating weights p Age 0.12 NS Body dissatisfaction Restraint (TEFQ) Depression (BDI) 0.05 NS TFEQ-R BDI Adjusted R NS, not significant. patients, as the affective part of dual pathway model of Stice et al. (43) predicts. (Repeating this analysis with the posttreatment scores gave almost identical results.) To demonstrate that the best way of describing the associations was that depression mediated the body-dissatisfaction effect, rather than vice versa (i.e., that body dissatisfaction mediated the depression effect), we also compared a model containing only depression (Model 3) with the model comparing both variables (Model 2). This shows that the unique variance explained by depression is reduced when body dissatisfaction is added to the model (from 22% to 12%, 45% reduction) but the reduction is much less, and the -coefficient remains strongly significant. This comparison provides additional support for a model in which depression is the mediator. We also tested the significance of the interaction between depressed mood and restraint in a multiple regression analysis. Age, body dissatisfaction, restraint, depression, and the restraint by depression interaction were included in the model (Table 3). The results show that there is a significant interaction effect and once the interaction is included, the main effect of depression is reduced, while high restraint becomes protective. The effect is illustrated in Figure 1 with participants classified into tertiles of depression and restraint. Only the highest and lowest tertile for each are shown to simplify the illustration. In the high-depression group, greater restraint is associated with higher levels of binge eating, whereas in the lower-depression groups, high restraint is associated with lower binge eating. Given that the lowest binge-eating score is for the highrestraint/low-depression group, it seems that restraint may be protective against binge eating for obese women who are not depressed. Figure 1: Binge-eating score in relation to levels of depression (BDI) and restraint. Longitudinal Analyses If the associations that are found in this model are assumed to be causal, then they have the following implications for the likely effects of treatment on binge eating. First, improved body satisfaction should be associated with reduced binge eating, even after taking account for changes in weight. Second, changes in restraint are unlikely to have any simple association with binge eating, because increased restraint might increase binge eating among the more depressed while decreasing binge eating among the less depressed. However, given that depression levels overall are likely to be reduced during treatment, the effect of increased restraint should tend to decrease binge eating; therefore, we predicted a positive association between binge-eating change and restraint change (i.e., individuals who became more restrained might be expected to binge less). Third, reducing depressed mood should have broadly positive effects on binge eating. Finally, on the basis of the crosssectional results, the largest reduction in binge eating should be among those who both decrease their level of depression and increase their level of restraint. Over the 12-week treatment, mean binge-eating score was reduced to 8.10 ( 6.5), body dissatisfaction to 41.5 ( 11.5), and BDI score to 7.8 ( 4.2). Restraint was increased to 11.8 ( 4.2). The mean post-treatment BMI was 35.7 kg/m 2 ( 9.7 kg/m 2 ). Table 4 shows the change score for each variable and the bivariate correlations between the change variables. As predicted, improved body satisfaction was associated with a greater reduction in binge eating, which persisted after controlling for weight loss (r 0.26; p 0.05). Increased restraint was not significantly associated with reduction in binge-eating score, although it was associated with greater weight loss. A greater reduction in depression was associated with lower levels of binge eating, even after controlling for weight loss (r 0.47; p 0.001) and with improved body satisfaction, after controlling for weight loss (r 0.30; p 0.01). 782 OBESITY RESEARCH Vol. 9 No. 12 December 2001

6 Table 4. Pearson correlations, means, and SDs of change scores in the longitudinal data (n 69) Binge-eating change Bodysatisfaction change Restraint change Depression change Mean change SD Binge-eating change* Body-dissatisfaction change 0.32, p Restraint change 0.19, p , p Depression change 0.57, p , p Weight loss 0.35, p , p , p , p * Decrease in scores on the Gormally BES. Decrease in scores on the body dissatisfaction scale. Increase in the restrained eating scale of TFEQ. Decrease in scores on the BDI. Decrease in weight (in kilograms). Regression analyses were used to investigate predictors of change in binge-eating score from baseline to posttreatment assessment (Table 5). In all models, group membership (S-CBT or M-CBT) and weight loss were included as control variables. As with the cross-sectional data, Model 1 included only the control variables and body-satisfaction change. Fifteen percent of the variance in change in bingeeating score was explained, with body-satisfaction change a significant predictor. Adding depression change (Model 2) substantially increased the explained variance in change in binge eating (to 29%) and reduced the unique variance explained by body satisfaction (from 6% to 1%), just as it had in the cross-sectional model. Table 5. Associations among change in BES and changes in body dissatisfaction and depression in the longitudinal data (n 69) Model 1 Model 2 sr 2 * sr 2 Treatment group Weight loss Body-dissatisfaction reduction Depression reduction Adjusted R * Square of semi-partial correlation. p p The effect of the depression by restraint interaction was evaluated to test the interaction that emerged in the crosssectional data (Table 6). The interaction was computed so that high scores reflected increases in restraint and decreases in depression to match the cross-sectional data. The effect came close to conventional levels of statistical significance (p 0.06), suggesting that binge eating improved most in those who became less depressed and more restrained. This is illustrated in Figure 2, where participants are classified according to whether they became less depressed vs. more depressed (or stayed the same), and less restrained vs. more restrained. Those who showed no change in restraint were not included. It can be seen that the greatest reduction in binge eating is in the group who Table 6. Changes in body dissatisfaction, restraint, and depression as predictors of change in binge eating weight Treatment group 0.04 NS Weight loss 0.16 NS Body-dissatisfaction reduction 0.11 NS Restraint increase 0.18 NS Depression reduction 0.14 NS Restraint increase depression reduction interaction 0.65 p 0.06 Adjusted R NS, not significant. p OBESITY RESEARCH Vol. 9 No. 12 December

7 Figure 2: Change in binge-eating score in relation to change in depression and restraint. experienced decreased depression and increased restraint. This supports the finding in the cross-sectional data that restraint is associated with low levels of binge eating, providing that the individual is not depressed. Discussion This study was designed to investigate the inter-relationships among body satisfaction, restraint, depression, and binge eating in an obese population referred for CBT. The baseline data showed that women who were less satisfied with their shape had higher binge-eating scores and that this effect was independent of age or body weight. The importance of this association was underlined by the longitudinal results, which showed that women whose body dissatisfaction decreased the most during treatment had the most improvement in binge eating, and, again, the effect was independent of weight change. These results support the trend in the new generation of obesity treatments to incorporate procedures designed to improve body image, not only to improve well-being, but also to reduce the future risk of binge eating (44,45). The second issue to be addressed was the mechanism through which body dissatisfaction might be linked with binge eating. Studies in the normal population have long assumed a restraint-based mechanism, although it has been argued that some of this work has used measures of restraint that incorporate elements of disinhibition in the scale and, thereby, may have exaggerated the strength of the association between restraint and binge eating (46,47). As discussed earlier, when the mediational model was tested statistically in a normal-weight student sample (20), restraint did not seem to be the primary mediator of the body dissatisfaction binge eating association, even though it was correlated with both body dissatisfaction and binge eating. In the present sample of obese women, the basic associations among body dissatisfaction, restraint, and binge eating, which have been found in most studies of normalweight populations, were not observed. Obese women who were more dissatisfied with their body shape were no more restrained, and obese women who were more restrained did not have higher binge-eating scores, so restraint could not be a mediator of the body satisfaction binge eating association. This confirms results from an extensive review of the literature relating restraint to binge eating among the obese (48). The reason that the correlates of restraint differ in obese and normal-weight women is not clear. One possibility is range restriction: the levels of restraint are very high among obese people who are seeking treatment and may fall within a range that is not associated with variation in either body dissatisfaction or binge eating. Another possibility is that there are different kinds of dietary restraint, some of which are more successful than others (49 51), and that the form of restraint practiced by obese people tends to be more protective. This is in line with previous research that has found that higher restraint is associated with better outcomes among obese women on a very-low-calorie diet (52). Whatever the explanation, these results must be taken to be encouraging insofar as restraint is a prominent feature of the advice given to the obese, and it is important to know that it is not toxic in its effects on the recipients. Indeed it might be timely to reconsider the evidence on harmfulness of dieting across the board, in the light of the current epidemic of obesity emerging in most industrialized nations (53). In support of the baseline findings, longitudinal analyses showed that there was no adverse effect of increased restraint over the intervention period. The general trend over treatment was toward greater restraint, and this was paralleled by a reduction in binge eating. There was also no evidence that a larger-than-average increase in restraint caused a lesser-than-average reduction in binge eating. This result to some extent confirms the existing clinical literature, which indicates that conventional CBT (which typically involves increased restraint) is not associated with increased binge eating, at least not during treatment (54). In fact obese binge-eaters seem to benefit from conventional CBT programs, despite earlier misgivings that the increased restraint would cause increased binge eating and, thereby, prevent any weight loss (55,56). The links with depression that emerged both in the crosssectional and longitudinal data argue strongly for much greater attention to mood among the obese, and especially 784 OBESITY RESEARCH Vol. 9 No. 12 December 2001

8 obese binge-eaters. In the baseline data, depression was associated both with body satisfaction and binge eating. The multiple regression analyses on the baseline data suggested that depression contributed independently to binge eating and partly mediated the body-dissatisfaction effect. Further analysis of the baseline data indicated that this model was more likely than a model in which body dissatisfaction mediates the association between binge eating and depression. This pattern was confirmed in the longitudinal data: reductions in depression were associated with reductions in binge eating, and reductions in depression partly mediated the effect of reduction in body dissatisfaction. These results suggest that reductions in depressed mood or improvements in well-being during obesity treatment might be expected to have enduring effects on eating control. This is broadly consistent with the conclusions of a recent review by the National Task Force on the Prevention and Treatment of Obesity (57), which suggests that although most obese people attempting to lose weight are not at risk of psychological distress or eating disorders, there may be a vulnerable subgroup with preexisting psychological problems (like depression), which may be exacerbated by weight-loss treatment. The report calls for vigilance among clinicians in identifying these at-risk individuals and providing appropriate treatment; however, because women with serious psychiatric conditions were excluded from this study, we cannot draw any conclusions about this. The interactions between restraint and depression in their association with binge eating that emerged in these analyses may also be important in understanding the processes involved. Laboratory studies in the normal-weight population show that restrained eaters are particularly susceptible to increased food intake when they are stressed or depressed (21,58). Moment-to-moment recording of mood and eating behavior has also shown that acutely low mood is a risk factor for a binge (22). In this study, the cross-sectional data indicated that the combination of high restraint and high depression was particularly linked with binge eating, but otherwise restraint was, if anything, protective. The pattern suggested by the baseline results received some confirmation in the longitudinal results, where the greatest reduction in binge eating came in the group who became less depressed and more restrained, as found by Stice et al. (23) in their nonclinical sample. These longitudinal data provide more robust evidence for the role of restraint and depression in mediating the relationship between body dissatisfaction and binge eating than have previous cross-sectional studies. The implications for treatment might be that so long as individuals are empowered to feel positive and optimistic, then restraint, or at least restraint in the form in which obese women practice it, could be therapeutic. There were some shortcomings of this study. The sample was comparatively small to examine such complex associations, although it benefited from having a longitudinal as well as a cross-sectional element. The obese participants in this study were not an unselected group from the community, but women who had been referred or had referred themselves for treatment, and, consequently, it would not be appropriate to extrapolate these results to all obese women. It should also be noted that the women in this study had an average age of 47 years, which is somewhat older than in other studies, and might also affect the generalization of the findings. Participants from two different treatment groups were combined for the analyses, although this may have had the advantage of giving more variation in the dependent variables. The sample was also restricted to women, and it would have been preferable to have an equally large sample of men. However, the results do seem to inform our understanding of the association between body image and binge eating in obesity, suggesting that management of depressed mood might usefully be considered as part of the process of maximizing the efficacy of weight-management programs. Acknowledgments The study was supported in part by a grant from Lambeth, Southwark, and Lewisham Health Authority. References 1. Marcus MD, Wing RR, Lamparski DM. Binge eating and dietary restraint in obese patients. Addict Behav. 1985;10: American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: American Psychiatric Association; Robertson DN, Palmer RL. The prevalence and correlates of binge eating in a British community sample of women with a history of obesity. Int J Eat Disord. 1997;22: Spitzer R, Devlin M, Walsh BT, et al. Binge eating disorder: a multisite field trial of the diagnostic criteria. Int J Eat Disord. 1992;11: Striegel-Moore RH, Wilson GT, Wilfley DE, Elder KA, Brownell KD. Binge eating in an obese community sample. Int J Eat Disord. 1998;23: Antony MM, Johnson WG, Carr-Nangle RE, Abel JL. Psychopathology correlates of binge eating and binge eating disorder. Compr Psychiatry. 1994;35: Cargill BR, Clark MM, Pera V, Niaura RS, Abrams DB. Binge eating, body image, depression, and self-efficacy in an obese clinical population. Obes Res. 1999;7: Mussell MP, Mitchell JE, de Zwaan M, Crosby RD, Seim HC, Crow SJ. Clinical characteristics associated with binge eating in obese females: a descriptive study. Int J Obes Relat Metab Disord. 1996;20: Telch CF, Stice E. Psychiatric comorbidity in women with binge eating disorder: prevalence rates from a non-treatmentseeking sample. J Consult Clin Psychol. 1998;66: Telch CF, Agras WS. Obesity, binge eating and psychopathology: are they related? Int J Eating Disord. 1994;15: Lloyd-Richardson EE, King TK, Forsyth LH, Clark MM. Body image evaluations in obese females with binge eating disorder. Eat Behav. 2000;1: OBESITY RESEARCH Vol. 9 No. 12 December

9 12. Miller PM, Watkins JA, Sargent RG, Rickert EJ. Selfefficacy in overweight individuals with binge eating disorder. Obes Res. 1999;7: Killen JD, Hayward C, Wilson DM, et al. Factors associated with eating disorder symptoms in a community sample of 6th and 7th grade girls. Int J Eating Disord. 1994;15: Polivy J, Herman CP. Dieting and binging: a causal analysis. Am Psychol. 1985;40: Stice E, Shaw HE. Adverse effects of the media portrayed thin-ideal on women and linkages to bulimic symptomatology. J Soc Clin Psychol. 1994;13: Striegel-Moore RH, Silberstein LR, Rodin J. The social self in bulimia nervosa: public self-consciousness, social anxiety, and perceived fraudulence. J Abnorm Psychol. 1993;102: Thompson JK, Coovert MD, Richards KJ, Johnson S, Cattarin J. Development of body image, eating disturbance, and general psychological functioning in female adolescents: covariance structure modeling and longitudinal investigations. Int J Eating Disord. 1995;18: Wardle J, Marsland L, Sheikh Y, Quinn M, Fedoroff I, Ogden J. Eating style and eating behaviour in adolescents. Appetite. 1992;18: Wardle J. Compulsive eating and dietary restraint. Br J Clin Psychol. 1987;26: Ricciardelli LA, Tate D, Williams RJ. Body dissatisfaction as a mediator of the relationship between dietary restraint and bulimic eating patterns. Appetite. 1997;29: Greeno CG, Wing RR. Stress-induced eating. Psychol Bull. 1994;115: Greeno CG, Wing RR, Shiffman S. Binge antecedents in obese women with and without binge eating disorder. J Consult Clin Psychol. 2000;68: Stice E, Akutagawa D, Gaggar A, Agras WS. Negative affect moderates the relation between dieting and binge eating. Int J Eating Disord. 2000;27: Shepherd H, Ricciardelli LA. Test of Stice s dual pathway model: dietary restraint and negative affect as mediators of bulimic behavior. Behav Res Ther. 1998;36: Stice E, Shaw HE, Nemeroff C. Dual pathway model of bulimia nervosa: longitudinal support for dietary restraint and affect-regulation mechanisms. J Soc Clin Psychol. 1998;17: Grilo CM, Masheb RM. Onset of dieting vs binge eating in outpatients with binge eating disorder. Int J Obes Relat Metab Disord. 2000;24: Mussell MP, Mitchell JE, Weller CL, Raymond NC, Crow SJ, Crosby RD. Onset of binge eating, dieting, obesity, and mood disorders among subjects seeking treatment for binge eating disorder. Int J Eating Disord. 1995;17: Spurrell EB, Wilfley DE, Tanofsky MB, Brownell KD. Age of onset for binge eating: are there different pathways to binge eating? Int J Eating Disord. 1997;21: Adami GF, Gandolfo P, Cocchi FH, Bauer B, Petti AR, Scopinaro N. Binge eating following biliopancreatic diversion for obesity. Appetite. 1995;25: Adami GF, Gandolfo P, Meneghelli A, Scopinaro N. Binge eating in obesity: a longitudinal study following biliopancreatic diversion. Int J Eating Disord. 1996;20: French SA, Jeffery RW, Sherwood NE, Neumark-Sztainer D. Prevalence and correlates of binge eating in a nonclinical sample of women enrolled in a weight gain prevention program. Int J Obes Relat Metab Disord. 1999;23: Marcus MD, Wing RR, Hopkins J. Obese binge-eaters: affect, cognitions, and response to behavioural weight control. J Consult Clin Psychol. 1988;56: Wilson GT, Nonas CA, Rosenblum GD. Assessment of binge eating in obese patients. Int J Eating Disord. 1993;13: Yanovski SZ, Sebring NG. Recorded food intake of obese women with binge eating disorder before and after weight loss. Int J Eating Disord. 1994;15: Stice E, Agras WS. Subtyping bulimic women along dietary restraint and negative affect dimensions. J Consult Clin Psychol. 1999;67: Rapoport L, Clark M, Wardle J. Evaluation of a modified cognitive-behavioural programme for weight management. Int J Obes Relat Metab Disord. 2000;24: Gormally J, Black S, Daston S, Rardin D. The assessment of binge eating severity among obese persons. Addict Behav. 1982;7: Sherwood NE, Jeffery RW, Wing RR. Binge status as a predictor of weight loss treatment outcome. Int J Obes Relat Metab Disord. 1999;23: Stunkard AJ, Messick S. The three-factor eating questionnaire to measure dietary restraint, disinhibition and hunger. J Psychosom Res. 1985;29: Rosen JC, Srebnik D, Saltzberg E, Wendt S. Development of a body image avoidance questionnaire. Psychol Assessment. 1991;3: Beck AT, Steer RA, Garbin MG. Psychometric properties of the Beck Depression Inventory: twenty-five years of evaluation. Clin Psychol Rev. 1988;8: Baron RM, Kenny DA. The moderator-mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. J Pers Soc Psychol. 1986; 51: Stice E. A review of the evidence for a sociocultural model of bulimia nervosa and an exploration of the mechanisms of action. Clin Psychol Rev. 1994;14: Wilson GT. Acceptance and change in the treatment of eating disorders and obesity. Behav Ther. 1996;27: Parham ES. Promoting body size acceptance in weight management counseling. J Am Diet Assoc. 1999;99: Gorman BS, Allison DB. Measures of restrained eating. In: Allison DB, ed. Handbook for Assessment Methods for Eating Behaviours and Weight-Related Problems: Measures, Theory and Research. Thousand Oaks, CA: Sage Publications; 1995, pp Lowe MR. The effects of dieting on eating behavior: a threefactor model. Psychol Bull. 1993;114: Howard CE, Porzelius LK. The role of dieting in binge eating disorder: etiology and treatment implications. Clin Psychol Rev. 1999;19: OBESITY RESEARCH Vol. 9 No. 12 December 2001

10 49. Allison DB, Kalinsky LB, Gorman BS. A comparison of the psychometric properties of three measures of dietary restraint. Psychol Assessment. 1992;4: Westenhoefer J, Broeckmann P, Munch AK, Pudel V. Cognitive control of eating behaviour and the disinhibition effect. Appetite. 1994;23: Williamson DA, Barker SE, Bertman LJ, Gleaves DH. Body image, body dysphoria, and dietary restraint: factor structure in nonclinical subjects. Behav Res Ther. 1995;33: LaPorte DJ, Stunkard AJ. Predicting attrition and adherence to a very low calorie diet: a prospective investigation of the eating inventory. Int J Obes Relat Metab Disord. 1990;14: World Health Organization. Obesity: Preventing and Managing the Global Epidemic. Geneva, Switzerland: World Health Organization; WHO/NUT/NCD/ Agras WS. Treatment of the obese binge eater. In: Brownell KD, Fairburn CG, eds. Eating Disorders and Obesity. New York, NY: The Guilford Press; Agras WS, Telch CF, Arnow B, Eldredge K, Marnell M. One-year follow-up of cognitive-behavioral therapy for obese individuals with binge eating disorder. J Consult Clin Psychol. 1997;65: Porzelius LK, Houston C, Smith M, Arfken C, Fisher E Jr. Comparison of a standard behavioral weight loss treatment and a binge eating weight loss treatment. Behav Ther. 1995; 26: National Task Force for the Prevention and Treatment of Obesity. Dieting and the development of eating disorders. Arch Intern Med. 2000;160: Wardle J, Gibson EL. Impact of stress on diet: processes and implications. In: Standfield S, Marmot MG, eds. Stress and the Heart. London, UK: BMJ Books; OBESITY RESEARCH Vol. 9 No. 12 December