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On the relationship between emotional and external eating behavior
Addictive Behavior\. Vol. 10. No. 5. pp. 585-594. 1995 Copyright G 1995 Elsevier Science Ltd Printed in the USA. All rights reszrved 0306.4603iYZ 59.50 -t .oo
Pergamon
0306-4603(95)00018-6
ON THE RELATIONSHIP BETWEEN EMOTIONAL AND EXTERNAL EATING BEHAVIOR TATJANA
VAN STRIEN and GERARD M. SCHIPPERS University of Nijmegen, The Netherlands
W. MILES COX North Chicago VA Medical Center/The Abstract -
Although there is a strong subscales for these behaviors
relationship
Chicago Medical School between
emotional
and external
eating,
have been constructed in the Dutch Eating Behavior Questionnaire. This study tries to establish whether this distinction is justified. We studied relationships among self-reported (I) degree of emotional and external eating behavior and (2) problems with (a) emotional distress and relationships, (b) stimulus-boundness (inappropriate amounts of either too much or too little exercise, work, leisure activities, and spending money), and (c) problems with substance use (alcohol, illicit drugs, nicotine. or caffeine) in a sample of female students. No relationships were found between either type of eating behavior and problems with substance use. Furthermore. the significant relationship between emotional and external eating behavior and stimulus-boundness disappeared in the subsample who had problems with oveieating. The fact that in all samples emotional eating was significantly related to problems with emotional distress and relationships (anxiety, depression, phobias. suicidal acts or ideations, intimate relations, and sexual contacts) but external eating was not, suggests that the two types of eating behaviors refer to independent constructs. Thus, the use of separate scales to measure these theoretically different aspects of overeating seems warranted. separate
The Dutch Eating Behavior Questionnaire (DEBQ; Van Strien, Frijters, Bergers, & Defares, 1986), which is now widely used (e.g., Grunert, 1989; Laessle, Tuschl, Kotthaus, & Pirke, 1989; Wardle, 1987), was developed to measure different aspects of eating behavior, each of which corresponds to a major theory on the etiology of overeating: (a) restriction of food intake (theory of restrained eating: Herman & Polivy, 1980) (b) overeating in response to negative emotions (psychosomatic theory; Bruch, 1964) and (c) eating in response to food-related stimuli, regardless of the internal state of hunger and satiety (externality theory: Schachter and Rodin, 1974). The DEBQ contains scales for restrained, emotional, and external eating behavior and has been shown to have high internal consistency, factorial validity, and dimensional stability (Van Strien, Frijters, Bergers, & Defares, 1986; Wardle, 1987). The Restrained Eating scale has acceptable predictive validity in that satisfactory relationships have been found between scores on the scale and daily caloric intake (Wardle & Beales, 1987), and the intake of fat and sugars (Van Strien, Frijters, Van Staveren, Defares, & Deurenberg, 1986). However, because there has been little prior work to establish the validity of the other two DEBQ scales (e.g., Van Strien & Bergers, 1988; Van Strien, Frijters, Roosen, Knuiman-Hijl, & Defares, 1985; Van Strien, Rookus, Bergers, Frijters, & Defares, 1986), the purpose of the present study was to do so.
We thank the anonymous reviewers for their constructive comments on an earlier draft of this manuscript. Reprint requests should be sent to Tatjana Van Strien. Psychological Laboratory. Katholieka Universiteit Nijmegen, Postbus 9104, 6500 HE Nijmegen, The Netherlands.
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et al.
Of particular interest for the present study is the strong relationship between the scales for emotional and external eating behavior found in earlier studies (Van Strien et al., 1985; Van Strien, Frijters, Bergers, & Defares, 1986; Van Strien & Bergers, 1988). Although this relationship is in line with both psychosomatic theory and externality theory, the use of separate scales to measure these theoretically different aspects of overeating is warranted only if it can also be empirically shown that they refer to independent constructs. More specifically, an essential difference between psychosomatic and externality theory is that in psychosomatic theory overeating is attributed to a confusion of physiological states accompanying negative emotions with physiological correlates of hunger and satiety. Furthermore, individuals who frequently resort to so-called emotional eating are considered to be more poorly adjusted and to have a deficient inner cognitive and affective structure, which may be accompanied by difficulties in labeling emotional states. Especially negative emotions may be experienced as diffuse states by individuals who frequently resort to emotional eating (Slochower, 1983). In contrast, in externality theory overeating is attributed to a general sensitivity to external cues, of which sensitivity to food cues such as,the sight and smell of food is but one aspect. Accordingly, externality theory refers to “external eating” as a heightened sensitivity to food cues. Further, persons who are external eaters are characterised as “stimulus bound,” in that they are “more efficient stimulus or information processors” (Schachter, 1971, p. 127). However, apart from the differences, psychosomatic theory and externality theory also share commonalities regarding the etiology of overeating. Both theories have in common that “obese eating patterns,” like emotional and external eating behavior, precede dieting, rather than being caused by dieting. This is in contrast with the theory of restrained eating behavior, which assumes that overeating is caused by dieting (Herman & Polivy, 1980). This theory is, however, out of the focus of the present study. Furthermore, in both theories individuals’ misperception of their internal state prior to eating is considered to be a causal factor in overeating (Robins & Fray, 1980). Finally, as was already briefly mentioned, both theories assume a strong relationship between emotional and external eating behavior. Slochower, one of the advocates of psychosomatic theory, showed in various experiments that emotionality and food cues operate conjointly to elicit eating behavior: a state of high uncontrollable anxiety was shown to enhance reactions to external cues (Slochower, 1983). In externality theory, a strong relationship between both types of eating behavior is also assumed because a high degree of emotionality, which is characteristic of many external eaters (e.g., Rodin, Elman, & Schachter, 1974), is seen as one of the aspects of the personality trait externality (e.g., Schachter & Rodin, 1974). The purpose of the present study was to provide more information about the construct validity of the Emotional and External Eating scales of the DEBQ. Specifically, two questions were addressed. First, could the strong relationships between both the scales found in other studies that is in line with both psychosomatic and externality theory, be replicated in the present study? Second, if so and in spite of their strong interrelationship, do the three scales represent theoretically meaningful and independent constructs in terms of their relationships to further self-reported noneating behaviors? Consistent with the stimulus-bound concept of externality theory, in which external eating is considered as just one aspect of the general personality trait externality (Schachter & Rodin, 1974; Rodin, 1980), we expected to find relationships between external eating and personal problems reflecting various aspects of externality, such
Overeating
587
as problems with substance use (alcohol, illicit drugs, nicotine, caffeine) and inappropriate amounts (either too much or too little) of the following behaviors: exercise, working, leisure activities, and spending money. The underlying rationale for these hypotheses is as follows: Because “the impinging stimulus is more likely to grip the attention of the stimulus-bound . . . subject” (Schachter, 1971, p. 139), such subjects may be more inclined than others to have an all-or-none approach to either the intake of various substances or participation in behaviors such as working or spending money. As is the case with “external eating” where overeating occurs only in the presence of tempting stimuli like the sight or smell of delicious food, stimulus-bound individuals may also be inclined to drink, spend, or work too much once the impinging stimulus is present; However, when the stimulus is out of sight it is also “out of mind.” On the basis of the prediction of psychosomatic theory that emotionality triggers emotional eating (Bruch, 1964), we expected to identify relationships between emotional eating and problems indicating emotional distress, such as anxiety, depression, phobias and suicidal acts or ideations, or relationship problems. Because of sex differences in both etiology (Van Strien & Bergers, 1988) and prevalence (Van Strien, Frijters, Bergers, & Defares, 1986) of emotional and external eating behavior, an exclusively female sample was chosen for the study. The various relationships were studied in a sample of female college students and a subsample indicating having problems with overeating. METHOD Subjects
Subjects were 271 female undergraduate psychology students who participated in a larger study on self-identified problems with addictive behaviors and emotional disturbances. The average age of the sample was 21.8 years (SD = 4.3); The average BMI (body mass index: weight/height x height) was 20.8 (SD = 2.2). Instruments
The Dutch Eating Behavior Questionnaire (DEBQ) contains 33 items. For the present study only the 23 items pertaining to emotional and external eating behavior are of relevance. The External Eating scale contains IO items (e.g., If food smells and looks good, do you eat more than usual? If you walk past the bakery, do you have the desire to buy something delicious?). The Emotional Eating scale contains 13 items (e.g., Do you have the desire to eat when you are irritated?; Do you have the desire to eat when you have nothing to do?). All items have a 5-option response format: (I) never, (2) seldom, (3) sometimes, (4) often, and (5) very often. Some items that are in a conditional format also have a “nonrelevant” response option (e.g., Do you have a desire to eat when you feel bored or restless?) This format was used because some subjects never experience particular emotions. In the present study, notrelevant responses were treated as missing data. Scores for each scale are obtained by dividing the sum of the item endorsements by the total number of items endorsed. A high score indicates a high degree of the eating behavior in question, and each scale has a 1 to 5 range of scores. The Dutch Problem History Questionnaire (DPHQ) is a translation of Cook’s (1987) Problem History Questionnaire (PHQ) and has been shown to provide an efficient research tool in terms of stability, internal consistency, and validity for studying multiple addictions within groups that are not in treatment for addictive or
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emotional problems (Cook, 1989; Schippers & Cox, 1994). The version used in the present study consists of 22 items with the following S-option response format: (I) This has never been a problem for me; (2) This was a problem for me at one time but is no longer a problem; (3) This is now a problem for me but is not serious; (4) This is a problem that has gone on long enough to concern me; and (5) This is a serious problem, and I am afraid that it is getting out of control. The first 10 items ask about problems with the following addictive substances and behaviors: alcohol, illicit drugs, not prescribed medicines, nicotine, caffeine, obesity (“overeating regularly”), binge eating (“binging on food”), anorexia (“dieting too strictly”), gambling, and shoplifting. Four items ask for inappropriate amounts (“either too much or too little”) of the following behaviors: exercise, working, leisure activities, and spending money. Two items deal with relationships: problems with intimate relationships generally and problems with sexual contacts specifically. Two items ask about partner violence, whether the subject has committed or been the victim of such an act. Finally, four items inquire about emotional disturbances and distress: anxiety, depression, phobias, and suicidal acts or ideations. Procedure
During their regular classes, students were asked to complete the two questionnaires and provide brief demographic information (viz., their age, sex, height, and weight). RESULTS
We first assessed whether individual DPHQ items could be combined into meaningful clusters of problems. The purpose in doing so was to be able to study relationships between (a) emotional eating and external eating behavior and (b) severity of problems with addictive substances and behaviors. We formed the clusters by (a) performing a principal components analysis with iterations (using varimax rotation) and (b) computing Cronbach’s alphas on the items within each cluster. The principal components analysis was computed from the intercorrelations of 16 DPHQ items. Six items were eliminated because of the low frequency with which they had been endorsed (illicit drugs, not prescribed drugs, shoplifting, gambling, committing violence against partner, and being the victim of partner violence). On the basis of a screen-plot and inspection of the best interpretable solution, it was decided to present the outcome of the four-factor solution. This solution accounted for 50.2% of the variance and the following items clustered (factor loadings in parentheses): (a) problems with relationships (.59), problems with sex (.52), anxiety (.67), depression (.73), phobias (.75), and suicidal acts and ideations (.66); (b) inappropriate amounts of exercise (.53), working (.76), leisure activities (.76), and spending money (.65); (c) obesity (.78), binge eating (.80), and anorexia (.74); (d) alcohol (.57), nicotine (go), and cafeine (.74). The following four clusters were formulated: (a) emotional and relationship problems - phobias, depression, anxiety, suicide, problems with relationships, and problems with sex; (b) Stimulus-boundness - problems with working, leisure activities, spending money, and exercise; (c) Eating problems: binge eating, obesity, anorexia; (d) Substance use problems - problems with nicotine, caffeine, and alcohol. Cronbach’s alphas performed on each cluster indicated satisfactory reliability, with the exception of the substance use problems cluster (see Table 1). Finally, for
Overeating
589
each subject we computed a score on each cluster by dividing the sum of item endorsements by the total number of items endorsed. A high score indicates a high degree of the self-identified addictive or emotional problem. To determine how scores on the emotional eating and external eating scales of the DEBQ and those on the problem clusters were interrelated, we computed Pearson product-moment correlation coefficients among these two DEBQ scales and the four clusters of problems. These coefficients, along with the means, standard deviations. and Cronbach’s alphas of the scales and clusters are presented in Table I. As was expected, emotional eating was found to be positively related to external eating, Further, both types of eating behavior were positively and significantly related to the cluster of eating problems. As in Cook’s (1987) study, each problem cluster was found to be significantly 0, < .lO) correlated with every other problem cluster. In order to explore the construct validity of the Emotional and External Eating scales, relationships between these two scales and the other scales and clusters were studied. Emotional eating was found to be related to all problem clusters, with the exception of the one indicating problems with substance use. However, the latter result should be interpreted cautiously because of the low reliability of the substance-use cluster. In contrast, external eating was related only to the clusters on stimulus-boundness and eating problems. However, even when significant, correlation coefficients were of low magnitude. To study the possibility that correlations would be higher in a subgroup who indicated having problems with overeating, we performed the same analyses on a subgroup of 17 female subjects having a score of 4 to 5 on the DPHQ “overeating regularly” item, thus indicating that they were concerned with their regular overeating or that overeating had become a serious problem for them. This subgroup had significantly higher mean scores on some scales than the subgroup of 252 subjects’ having a score of 1 on this DPHQ item indicating that overeating had never been a problem for them. Higher scores were found for emotional eating behaviour (r(215) = -3.76, p < .OO;M no-problem group = 2.62, SD = .71) and on the clusters indicating (a) emotional and relationship problems [t(267) = -2.34, p < .03; M no-problem group = 1.56, SD = .64]; (b) stimulus boundness [r(267) = -3.18, p < .OO; M noproblem group = 1.74, SD = .63]; (c) substance use problems [t(267) = -2.25. p < .03; M no-problem group = I .30, SD = .44]. No differences were found between these groups with respect to external eating behaviour. r(213) = - 1.4, ns; M noproblem group = 2.96, SD = 55. However, the mean BMI of this subgroup is significantly higher than that of the subgroup who had no problems with overeating, t(266) = -3.14, p < .OO;M subgroup = 22.2, SD = 2.0; M no-problem group = 20.4. SD = 1.9. The Pearson product-moment correlation coefficients, along with the means and standard deviations of the scales and clusters of the subgroup (in parentheses) is presented in Table I .? As was expected, much stronger Pearson product-moment correlation coefficients were generally found in the subgroup. Specifically, the emotional and external eating scales were significantly related. Further, emotional eating was significantly related ‘Due to missing data some scales or clusters have less than 252 subjects in the group having no problems with overeating. ?Because classification of subjects in the subgroup was based on their scores on overeating and overeating forms part of the cluster of eating problems. the cluster on eating problems was omitted from the analyses.
**p < .05. ***p < .Ol.
*p < .lO.
Cronbach’s alpha
sd
m
Scales/clusters 1. Emotional eating 2. External eating 3. Emotional and relationship problems 4. Stimulus-boundness 5. Eating problems 6. Substance use problems
Table 1. Correlations,
(.48**) f.24)
.13** .17*** .33*** .Ol
f.09) 2.73 (3.31) .77 f.80) .94
(.53**)
.49***
I
.04
f-.36)
f.24) f.15)
3.02 (3.16) .56 (.46) .82
.19***
.06 .15***
2
f.37)
(.ll) I .64 (2.07) .68 f.88) .80
.33*** .23*** .08*
3
Scales/clusters
f.35) I .84 (2.24) .68 f.56) .55
.25*** l8***
4
I .48 (2.34) .70 f.54) .65
.19***
5
1.34 (1.55) .46 t.53) .23
6
means, standard deviations and Cronbach’s alphas of the scales and clusters of the DEBQ, and the DPHQ in total sample and in subsample () who had problems with overeating
Overeating
WI
to the cluster of emotional and relationship problems. However, no significant relationship was found between emotional eating and the cluster on stimulus-boundness or substance-use problems nor between external eating and any problem cluster. To further explore the hypothesis that emotional eating is related to negative emotions and external eating to stimulus-boundness. we performed both in the total sample and in the subgroup hierarchical multiple regression analyses with “negative emotions” (the six items that form the emotional and relationship problems cluster) and the cluster on stimulus-boundness as the independent variables, and the Emotional and External Eating scales as the dependent variables. The independent variables were entered in a stepwise incremental fashion and the significance of change in explained variance was determined at each step in the analysis (see Table 2). The variance explained in the scores on emotional eating in the entire sample of 271 female subjects, reached significance when the six “negative emotion” items were entered as independent variables. A significant increase in explained variance was obtained after including the cluster on stimulus-boundness at Step 2. However, the R' associated with the regression equation containing the two clusters together was only .03. Inspection of the beta coefficients associated with the clusters at the various steps of the incremental regression analysis revealed the following. The six items cluster on “negative emotions” no longer contributed significantly to emotional eating when the cluster on stimulus-boundness was included in the analysis at Step 2. In the case of the scores on external eating, the explained variance was not significant when the six “negative emotion” items were entered in the regression equation. A significant increase in explained variance was found when the cluster on stimulus-boundness was entered at Step 2. However, the R' associated with the regression equation containing all clusters was only .02. The significant contribution of stimulus boundness in contrast with the six “negative emotions” was confirmed in the beta coefficients. A different picture emerged in the subgroup (see Table 2). In the case of emotional eating the explained variance reached significance when the six “negative emotion” items were entered as independent variables, but no significant increase in explained variance was obtained after including the cluster on stimulus-boundness at Step 2 (see Table 2). The R? associated with the regression equation containing the two clusters together was .23, as can be seen in Table 2. Inspection of the beta coefficients associated with the clusters at the various steps of the incremental regression analysis revealed that the six “negative emotion” items continued to contribute significantly (although at borderline) to emotional eating when the cluster on stimulus-boundness was included in the analysis at Step 2. In the case of external eating in the subgroup, the regression equation revealed no significant effects. DISCUSSION
As expected, significant relationships were found between the Emotional Eating and the External Eating scales of the DEBQ. This outcome is consistent both with earlier findings and with both psychosomatic and externality theory. Further, emotional eating was significantly related to the emotional problems clusters of the DPHQ that reflected anxiety, depression, suicidal feelings, and problems with relationships and sex.
.02 (.23) .oo (.OO) .03 (.23)
Step I. Emotional and relationship problems Step 2. Stimulus-boundness Total R’
a= R? in first step of analysis. b.qfundurd error = .06 f.25). ‘stundurd error = .06 t.28). dBeta coefficient at step 2 (in the equation
R? change;’
Clusters
containing
.08 (.45Pd I4 (.07)h
Beta
eating
also stimulus-boundness).
.03 (.05) .03 (ns)
Sign RI change
Emotional
ns (.09) .03 (ns)
Sign T
.OO l.06) .02 (.OO) .02 (.06)
R’ Change
ns (ns) .03 (ns)
Sign R’ change
External
.Ol (.22)‘,” .I4 (.07)’
Beta
eating
ns (ns) .03 (ns)
Sign. T
Table 2. Hierarchical multiple regression analysis of emotional and relationship problems (Step I) and stimulus-boundness (Step 2) on emotional and external eating behavior in total sample in the subsample () who had problems with overeating (F-change, significance R’-change, beta coefficients, and significance T)
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The relationship between emotional eating and emotional problems found in the present study is also consistent with our earlier finding that among women emotional eating is associated with feelings of inadequacy, low self-esteem, low sociability, and social anxiety (Van Strien et al., 198.5; Van Strien & Bergers, 1988). Thus, it appears that the DEBQ Emotional Eating scale measures a type of overeating that closely corresponds to the psychosomatic view that overeating in some individuals is associated with emotional distress (Bruch, 1964; Ganley, 1989).? It should be recalled, however, that when the cluster on stimulus-boundness was removed from the emotional problems cluster, that cluster contributed significantly to emotional eating only in the subsample who reported having serious problems with overeating. This suggests that in samples having less serious problems with overeating the contribution of emotional problems to emotional eating is due mainly to problems related to stimulus-boundness such as inappropriate amounts of exercise, working, leisure activities, and spending money, rather than expressed subjective emotional distress per se. No relationship was found between the External Eating scale and the emotional problems cluster. In addition, only in the total sample was a significant relationship found between scores on the DEBQ External Eating scale and the cluster on stimulus-boundness (i.e., exercise, working, leisure activities, and spending money). The absence of a significant relationship between external eating and the cluster on stimulus-boundness in the subsamples having self-reported problems with overeating and the finding that in the entire sample this cluster accounted for only a small proportion of the total variance in external eating behavior, provides only weak support for the view that the DEBQ External Eating scale measures a type of eating behavior that coincides with the stimulus-binding concept in externality theory (Schachter and Rodin, 1974). However, Nisbett and Temoshok (1976) and Isbitsky and White (1981) questioned the validity of a broad cognitive style such as stimulusbinding. The high correlations with external and emotional eating in both the group as a whole and in the subgroup, and the lack of correlation between external eating and stimulus boundness seem to argue for little relevance of the concept of externality to understanding eating problems. Nevertheless, it would be premature to altogether reject externality theory or its accompanying measurement instrument, the DEBQ External Eating Behaviour scale. Findings may well be different in other samples such as males. as external eating may be much more prevalent than emotional eating in males than in females (Van Strien, Frijters, Bergers, & Defares, 1986). In any event, the fact that emotional eating showed a significant relationship with emotional problems, but external eating did not, suggests that the two types of eating behaviors reflect independent constructs. This means that the Emotional and External Eating scales of the DEBQ measure theoretically different aspects of overeating (see also Van Strien, Frijters et al., 1986a; Van Strien, Rookus et al., 1986b). and continued use of both scales is warranted. One final caveat should be mentioned. In the present sample of female students and the subsamples who had problems with overeating, neither emotional eating nor external eating was significantly related to substance use problems (i.e., problems ‘Allison and Heshka (1993a) critical analysis of psychosomatic scale (Allison and Heshka, 1993b) will be discussed elsewhere. flawed (Van Strien, in press).
theory and the DEBQ Emotional Eating as their analysis seems to be seriously
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related to the use of alcohol, illicit drugs, nicotine, or caffeine). This may be due to the fact that substance-use problems had a very low prevalence rate in the present sample. Similar low rates have been found among both Dutch and American male and female college students (see Schippers & Cox, 1994). In a sample with higher substance-use base rates (e.g., clinical samples with identified substance use), it might well be that eating and substance-use problems would be related to each other (see for example Koepp, Schidbach, Schmager, & Rohner, 1993). REFERENCES Allison, D. B., & Heshka, S. (1993a). Emotion and eating in obesity? A critical analysis. In~erntrrionu/ Joarnal
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Allison, D. B., & Heshka, S. (1993b). Social desirability and response bias in self-reports of “emotional eating.” Eating Disorders: The Journal of Treatment and Prevention, 1,31-38. Bruch, H. (1964). Psychological aspects in overeating and obesity. Psychosomatics. 5, 269-274. Cook, D. R. (1987). Self-identified addictions and emotional disturbances in a sample of college students. Psychology
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Schachter, S., & Rodin, J. (1974). Obese humans and rats. Washington, DC: ErlbaumIHalsted. Schippers, G., & Cox, W. M. (1994). Problem perception and addictive behaviors among Dutch and American college students. Drug: Edacarion, prevention and policy, 1,27-35. Slochower, J. A. (1983). Excessive eating. The role of emotions and environment. New York: Human Sciences Press. Van Strien, T., Frijters, J. E. R., Bergers, G. P. A., & Defares. P. B. (1986). The Dutch Eating Behaviour Questionnaire (DEBQ) for assessment of restrained, emotional and external eating behaviour. International Journal
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Pergamon
0306-4603(95)00018-6
ON THE RELATIONSHIP BETWEEN EMOTIONAL AND EXTERNAL EATING BEHAVIOR TATJANA
VAN STRIEN and GERARD M. SCHIPPERS University of Nijmegen, The Netherlands
W. MILES COX North Chicago VA Medical Center/The Abstract -
Although there is a strong subscales for these behaviors
relationship
Chicago Medical School between
emotional
and external
eating,
have been constructed in the Dutch Eating Behavior Questionnaire. This study tries to establish whether this distinction is justified. We studied relationships among self-reported (I) degree of emotional and external eating behavior and (2) problems with (a) emotional distress and relationships, (b) stimulus-boundness (inappropriate amounts of either too much or too little exercise, work, leisure activities, and spending money), and (c) problems with substance use (alcohol, illicit drugs, nicotine. or caffeine) in a sample of female students. No relationships were found between either type of eating behavior and problems with substance use. Furthermore. the significant relationship between emotional and external eating behavior and stimulus-boundness disappeared in the subsample who had problems with oveieating. The fact that in all samples emotional eating was significantly related to problems with emotional distress and relationships (anxiety, depression, phobias. suicidal acts or ideations, intimate relations, and sexual contacts) but external eating was not, suggests that the two types of eating behaviors refer to independent constructs. Thus, the use of separate scales to measure these theoretically different aspects of overeating seems warranted. separate
The Dutch Eating Behavior Questionnaire (DEBQ; Van Strien, Frijters, Bergers, & Defares, 1986), which is now widely used (e.g., Grunert, 1989; Laessle, Tuschl, Kotthaus, & Pirke, 1989; Wardle, 1987), was developed to measure different aspects of eating behavior, each of which corresponds to a major theory on the etiology of overeating: (a) restriction of food intake (theory of restrained eating: Herman & Polivy, 1980) (b) overeating in response to negative emotions (psychosomatic theory; Bruch, 1964) and (c) eating in response to food-related stimuli, regardless of the internal state of hunger and satiety (externality theory: Schachter and Rodin, 1974). The DEBQ contains scales for restrained, emotional, and external eating behavior and has been shown to have high internal consistency, factorial validity, and dimensional stability (Van Strien, Frijters, Bergers, & Defares, 1986; Wardle, 1987). The Restrained Eating scale has acceptable predictive validity in that satisfactory relationships have been found between scores on the scale and daily caloric intake (Wardle & Beales, 1987), and the intake of fat and sugars (Van Strien, Frijters, Van Staveren, Defares, & Deurenberg, 1986). However, because there has been little prior work to establish the validity of the other two DEBQ scales (e.g., Van Strien & Bergers, 1988; Van Strien, Frijters, Roosen, Knuiman-Hijl, & Defares, 1985; Van Strien, Rookus, Bergers, Frijters, & Defares, 1986), the purpose of the present study was to do so.
We thank the anonymous reviewers for their constructive comments on an earlier draft of this manuscript. Reprint requests should be sent to Tatjana Van Strien. Psychological Laboratory. Katholieka Universiteit Nijmegen, Postbus 9104, 6500 HE Nijmegen, The Netherlands.
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et al.
Of particular interest for the present study is the strong relationship between the scales for emotional and external eating behavior found in earlier studies (Van Strien et al., 1985; Van Strien, Frijters, Bergers, & Defares, 1986; Van Strien & Bergers, 1988). Although this relationship is in line with both psychosomatic theory and externality theory, the use of separate scales to measure these theoretically different aspects of overeating is warranted only if it can also be empirically shown that they refer to independent constructs. More specifically, an essential difference between psychosomatic and externality theory is that in psychosomatic theory overeating is attributed to a confusion of physiological states accompanying negative emotions with physiological correlates of hunger and satiety. Furthermore, individuals who frequently resort to so-called emotional eating are considered to be more poorly adjusted and to have a deficient inner cognitive and affective structure, which may be accompanied by difficulties in labeling emotional states. Especially negative emotions may be experienced as diffuse states by individuals who frequently resort to emotional eating (Slochower, 1983). In contrast, in externality theory overeating is attributed to a general sensitivity to external cues, of which sensitivity to food cues such as,the sight and smell of food is but one aspect. Accordingly, externality theory refers to “external eating” as a heightened sensitivity to food cues. Further, persons who are external eaters are characterised as “stimulus bound,” in that they are “more efficient stimulus or information processors” (Schachter, 1971, p. 127). However, apart from the differences, psychosomatic theory and externality theory also share commonalities regarding the etiology of overeating. Both theories have in common that “obese eating patterns,” like emotional and external eating behavior, precede dieting, rather than being caused by dieting. This is in contrast with the theory of restrained eating behavior, which assumes that overeating is caused by dieting (Herman & Polivy, 1980). This theory is, however, out of the focus of the present study. Furthermore, in both theories individuals’ misperception of their internal state prior to eating is considered to be a causal factor in overeating (Robins & Fray, 1980). Finally, as was already briefly mentioned, both theories assume a strong relationship between emotional and external eating behavior. Slochower, one of the advocates of psychosomatic theory, showed in various experiments that emotionality and food cues operate conjointly to elicit eating behavior: a state of high uncontrollable anxiety was shown to enhance reactions to external cues (Slochower, 1983). In externality theory, a strong relationship between both types of eating behavior is also assumed because a high degree of emotionality, which is characteristic of many external eaters (e.g., Rodin, Elman, & Schachter, 1974), is seen as one of the aspects of the personality trait externality (e.g., Schachter & Rodin, 1974). The purpose of the present study was to provide more information about the construct validity of the Emotional and External Eating scales of the DEBQ. Specifically, two questions were addressed. First, could the strong relationships between both the scales found in other studies that is in line with both psychosomatic and externality theory, be replicated in the present study? Second, if so and in spite of their strong interrelationship, do the three scales represent theoretically meaningful and independent constructs in terms of their relationships to further self-reported noneating behaviors? Consistent with the stimulus-bound concept of externality theory, in which external eating is considered as just one aspect of the general personality trait externality (Schachter & Rodin, 1974; Rodin, 1980), we expected to find relationships between external eating and personal problems reflecting various aspects of externality, such
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as problems with substance use (alcohol, illicit drugs, nicotine, caffeine) and inappropriate amounts (either too much or too little) of the following behaviors: exercise, working, leisure activities, and spending money. The underlying rationale for these hypotheses is as follows: Because “the impinging stimulus is more likely to grip the attention of the stimulus-bound . . . subject” (Schachter, 1971, p. 139), such subjects may be more inclined than others to have an all-or-none approach to either the intake of various substances or participation in behaviors such as working or spending money. As is the case with “external eating” where overeating occurs only in the presence of tempting stimuli like the sight or smell of delicious food, stimulus-bound individuals may also be inclined to drink, spend, or work too much once the impinging stimulus is present; However, when the stimulus is out of sight it is also “out of mind.” On the basis of the prediction of psychosomatic theory that emotionality triggers emotional eating (Bruch, 1964), we expected to identify relationships between emotional eating and problems indicating emotional distress, such as anxiety, depression, phobias and suicidal acts or ideations, or relationship problems. Because of sex differences in both etiology (Van Strien & Bergers, 1988) and prevalence (Van Strien, Frijters, Bergers, & Defares, 1986) of emotional and external eating behavior, an exclusively female sample was chosen for the study. The various relationships were studied in a sample of female college students and a subsample indicating having problems with overeating. METHOD Subjects
Subjects were 271 female undergraduate psychology students who participated in a larger study on self-identified problems with addictive behaviors and emotional disturbances. The average age of the sample was 21.8 years (SD = 4.3); The average BMI (body mass index: weight/height x height) was 20.8 (SD = 2.2). Instruments
The Dutch Eating Behavior Questionnaire (DEBQ) contains 33 items. For the present study only the 23 items pertaining to emotional and external eating behavior are of relevance. The External Eating scale contains IO items (e.g., If food smells and looks good, do you eat more than usual? If you walk past the bakery, do you have the desire to buy something delicious?). The Emotional Eating scale contains 13 items (e.g., Do you have the desire to eat when you are irritated?; Do you have the desire to eat when you have nothing to do?). All items have a 5-option response format: (I) never, (2) seldom, (3) sometimes, (4) often, and (5) very often. Some items that are in a conditional format also have a “nonrelevant” response option (e.g., Do you have a desire to eat when you feel bored or restless?) This format was used because some subjects never experience particular emotions. In the present study, notrelevant responses were treated as missing data. Scores for each scale are obtained by dividing the sum of the item endorsements by the total number of items endorsed. A high score indicates a high degree of the eating behavior in question, and each scale has a 1 to 5 range of scores. The Dutch Problem History Questionnaire (DPHQ) is a translation of Cook’s (1987) Problem History Questionnaire (PHQ) and has been shown to provide an efficient research tool in terms of stability, internal consistency, and validity for studying multiple addictions within groups that are not in treatment for addictive or
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emotional problems (Cook, 1989; Schippers & Cox, 1994). The version used in the present study consists of 22 items with the following S-option response format: (I) This has never been a problem for me; (2) This was a problem for me at one time but is no longer a problem; (3) This is now a problem for me but is not serious; (4) This is a problem that has gone on long enough to concern me; and (5) This is a serious problem, and I am afraid that it is getting out of control. The first 10 items ask about problems with the following addictive substances and behaviors: alcohol, illicit drugs, not prescribed medicines, nicotine, caffeine, obesity (“overeating regularly”), binge eating (“binging on food”), anorexia (“dieting too strictly”), gambling, and shoplifting. Four items ask for inappropriate amounts (“either too much or too little”) of the following behaviors: exercise, working, leisure activities, and spending money. Two items deal with relationships: problems with intimate relationships generally and problems with sexual contacts specifically. Two items ask about partner violence, whether the subject has committed or been the victim of such an act. Finally, four items inquire about emotional disturbances and distress: anxiety, depression, phobias, and suicidal acts or ideations. Procedure
During their regular classes, students were asked to complete the two questionnaires and provide brief demographic information (viz., their age, sex, height, and weight). RESULTS
We first assessed whether individual DPHQ items could be combined into meaningful clusters of problems. The purpose in doing so was to be able to study relationships between (a) emotional eating and external eating behavior and (b) severity of problems with addictive substances and behaviors. We formed the clusters by (a) performing a principal components analysis with iterations (using varimax rotation) and (b) computing Cronbach’s alphas on the items within each cluster. The principal components analysis was computed from the intercorrelations of 16 DPHQ items. Six items were eliminated because of the low frequency with which they had been endorsed (illicit drugs, not prescribed drugs, shoplifting, gambling, committing violence against partner, and being the victim of partner violence). On the basis of a screen-plot and inspection of the best interpretable solution, it was decided to present the outcome of the four-factor solution. This solution accounted for 50.2% of the variance and the following items clustered (factor loadings in parentheses): (a) problems with relationships (.59), problems with sex (.52), anxiety (.67), depression (.73), phobias (.75), and suicidal acts and ideations (.66); (b) inappropriate amounts of exercise (.53), working (.76), leisure activities (.76), and spending money (.65); (c) obesity (.78), binge eating (.80), and anorexia (.74); (d) alcohol (.57), nicotine (go), and cafeine (.74). The following four clusters were formulated: (a) emotional and relationship problems - phobias, depression, anxiety, suicide, problems with relationships, and problems with sex; (b) Stimulus-boundness - problems with working, leisure activities, spending money, and exercise; (c) Eating problems: binge eating, obesity, anorexia; (d) Substance use problems - problems with nicotine, caffeine, and alcohol. Cronbach’s alphas performed on each cluster indicated satisfactory reliability, with the exception of the substance use problems cluster (see Table 1). Finally, for
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each subject we computed a score on each cluster by dividing the sum of item endorsements by the total number of items endorsed. A high score indicates a high degree of the self-identified addictive or emotional problem. To determine how scores on the emotional eating and external eating scales of the DEBQ and those on the problem clusters were interrelated, we computed Pearson product-moment correlation coefficients among these two DEBQ scales and the four clusters of problems. These coefficients, along with the means, standard deviations. and Cronbach’s alphas of the scales and clusters are presented in Table I. As was expected, emotional eating was found to be positively related to external eating, Further, both types of eating behavior were positively and significantly related to the cluster of eating problems. As in Cook’s (1987) study, each problem cluster was found to be significantly 0, < .lO) correlated with every other problem cluster. In order to explore the construct validity of the Emotional and External Eating scales, relationships between these two scales and the other scales and clusters were studied. Emotional eating was found to be related to all problem clusters, with the exception of the one indicating problems with substance use. However, the latter result should be interpreted cautiously because of the low reliability of the substance-use cluster. In contrast, external eating was related only to the clusters on stimulus-boundness and eating problems. However, even when significant, correlation coefficients were of low magnitude. To study the possibility that correlations would be higher in a subgroup who indicated having problems with overeating, we performed the same analyses on a subgroup of 17 female subjects having a score of 4 to 5 on the DPHQ “overeating regularly” item, thus indicating that they were concerned with their regular overeating or that overeating had become a serious problem for them. This subgroup had significantly higher mean scores on some scales than the subgroup of 252 subjects’ having a score of 1 on this DPHQ item indicating that overeating had never been a problem for them. Higher scores were found for emotional eating behaviour (r(215) = -3.76, p < .OO;M no-problem group = 2.62, SD = .71) and on the clusters indicating (a) emotional and relationship problems [t(267) = -2.34, p < .03; M no-problem group = 1.56, SD = .64]; (b) stimulus boundness [r(267) = -3.18, p < .OO; M noproblem group = 1.74, SD = .63]; (c) substance use problems [t(267) = -2.25. p < .03; M no-problem group = I .30, SD = .44]. No differences were found between these groups with respect to external eating behaviour. r(213) = - 1.4, ns; M noproblem group = 2.96, SD = 55. However, the mean BMI of this subgroup is significantly higher than that of the subgroup who had no problems with overeating, t(266) = -3.14, p < .OO;M subgroup = 22.2, SD = 2.0; M no-problem group = 20.4. SD = 1.9. The Pearson product-moment correlation coefficients, along with the means and standard deviations of the scales and clusters of the subgroup (in parentheses) is presented in Table I .? As was expected, much stronger Pearson product-moment correlation coefficients were generally found in the subgroup. Specifically, the emotional and external eating scales were significantly related. Further, emotional eating was significantly related ‘Due to missing data some scales or clusters have less than 252 subjects in the group having no problems with overeating. ?Because classification of subjects in the subgroup was based on their scores on overeating and overeating forms part of the cluster of eating problems. the cluster on eating problems was omitted from the analyses.
**p < .05. ***p < .Ol.
*p < .lO.
Cronbach’s alpha
sd
m
Scales/clusters 1. Emotional eating 2. External eating 3. Emotional and relationship problems 4. Stimulus-boundness 5. Eating problems 6. Substance use problems
Table 1. Correlations,
(.48**) f.24)
.13** .17*** .33*** .Ol
f.09) 2.73 (3.31) .77 f.80) .94
(.53**)
.49***
I
.04
f-.36)
f.24) f.15)
3.02 (3.16) .56 (.46) .82
.19***
.06 .15***
2
f.37)
(.ll) I .64 (2.07) .68 f.88) .80
.33*** .23*** .08*
3
Scales/clusters
f.35) I .84 (2.24) .68 f.56) .55
.25*** l8***
4
I .48 (2.34) .70 f.54) .65
.19***
5
1.34 (1.55) .46 t.53) .23
6
means, standard deviations and Cronbach’s alphas of the scales and clusters of the DEBQ, and the DPHQ in total sample and in subsample () who had problems with overeating
Overeating
WI
to the cluster of emotional and relationship problems. However, no significant relationship was found between emotional eating and the cluster on stimulus-boundness or substance-use problems nor between external eating and any problem cluster. To further explore the hypothesis that emotional eating is related to negative emotions and external eating to stimulus-boundness. we performed both in the total sample and in the subgroup hierarchical multiple regression analyses with “negative emotions” (the six items that form the emotional and relationship problems cluster) and the cluster on stimulus-boundness as the independent variables, and the Emotional and External Eating scales as the dependent variables. The independent variables were entered in a stepwise incremental fashion and the significance of change in explained variance was determined at each step in the analysis (see Table 2). The variance explained in the scores on emotional eating in the entire sample of 271 female subjects, reached significance when the six “negative emotion” items were entered as independent variables. A significant increase in explained variance was obtained after including the cluster on stimulus-boundness at Step 2. However, the R' associated with the regression equation containing the two clusters together was only .03. Inspection of the beta coefficients associated with the clusters at the various steps of the incremental regression analysis revealed the following. The six items cluster on “negative emotions” no longer contributed significantly to emotional eating when the cluster on stimulus-boundness was included in the analysis at Step 2. In the case of the scores on external eating, the explained variance was not significant when the six “negative emotion” items were entered in the regression equation. A significant increase in explained variance was found when the cluster on stimulus-boundness was entered at Step 2. However, the R' associated with the regression equation containing all clusters was only .02. The significant contribution of stimulus boundness in contrast with the six “negative emotions” was confirmed in the beta coefficients. A different picture emerged in the subgroup (see Table 2). In the case of emotional eating the explained variance reached significance when the six “negative emotion” items were entered as independent variables, but no significant increase in explained variance was obtained after including the cluster on stimulus-boundness at Step 2 (see Table 2). The R? associated with the regression equation containing the two clusters together was .23, as can be seen in Table 2. Inspection of the beta coefficients associated with the clusters at the various steps of the incremental regression analysis revealed that the six “negative emotion” items continued to contribute significantly (although at borderline) to emotional eating when the cluster on stimulus-boundness was included in the analysis at Step 2. In the case of external eating in the subgroup, the regression equation revealed no significant effects. DISCUSSION
As expected, significant relationships were found between the Emotional Eating and the External Eating scales of the DEBQ. This outcome is consistent both with earlier findings and with both psychosomatic and externality theory. Further, emotional eating was significantly related to the emotional problems clusters of the DPHQ that reflected anxiety, depression, suicidal feelings, and problems with relationships and sex.
.02 (.23) .oo (.OO) .03 (.23)
Step I. Emotional and relationship problems Step 2. Stimulus-boundness Total R’
a= R? in first step of analysis. b.qfundurd error = .06 f.25). ‘stundurd error = .06 t.28). dBeta coefficient at step 2 (in the equation
R? change;’
Clusters
containing
.08 (.45Pd I4 (.07)h
Beta
eating
also stimulus-boundness).
.03 (.05) .03 (ns)
Sign RI change
Emotional
ns (.09) .03 (ns)
Sign T
.OO l.06) .02 (.OO) .02 (.06)
R’ Change
ns (ns) .03 (ns)
Sign R’ change
External
.Ol (.22)‘,” .I4 (.07)’
Beta
eating
ns (ns) .03 (ns)
Sign. T
Table 2. Hierarchical multiple regression analysis of emotional and relationship problems (Step I) and stimulus-boundness (Step 2) on emotional and external eating behavior in total sample in the subsample () who had problems with overeating (F-change, significance R’-change, beta coefficients, and significance T)
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The relationship between emotional eating and emotional problems found in the present study is also consistent with our earlier finding that among women emotional eating is associated with feelings of inadequacy, low self-esteem, low sociability, and social anxiety (Van Strien et al., 198.5; Van Strien & Bergers, 1988). Thus, it appears that the DEBQ Emotional Eating scale measures a type of overeating that closely corresponds to the psychosomatic view that overeating in some individuals is associated with emotional distress (Bruch, 1964; Ganley, 1989).? It should be recalled, however, that when the cluster on stimulus-boundness was removed from the emotional problems cluster, that cluster contributed significantly to emotional eating only in the subsample who reported having serious problems with overeating. This suggests that in samples having less serious problems with overeating the contribution of emotional problems to emotional eating is due mainly to problems related to stimulus-boundness such as inappropriate amounts of exercise, working, leisure activities, and spending money, rather than expressed subjective emotional distress per se. No relationship was found between the External Eating scale and the emotional problems cluster. In addition, only in the total sample was a significant relationship found between scores on the DEBQ External Eating scale and the cluster on stimulus-boundness (i.e., exercise, working, leisure activities, and spending money). The absence of a significant relationship between external eating and the cluster on stimulus-boundness in the subsamples having self-reported problems with overeating and the finding that in the entire sample this cluster accounted for only a small proportion of the total variance in external eating behavior, provides only weak support for the view that the DEBQ External Eating scale measures a type of eating behavior that coincides with the stimulus-binding concept in externality theory (Schachter and Rodin, 1974). However, Nisbett and Temoshok (1976) and Isbitsky and White (1981) questioned the validity of a broad cognitive style such as stimulusbinding. The high correlations with external and emotional eating in both the group as a whole and in the subgroup, and the lack of correlation between external eating and stimulus boundness seem to argue for little relevance of the concept of externality to understanding eating problems. Nevertheless, it would be premature to altogether reject externality theory or its accompanying measurement instrument, the DEBQ External Eating Behaviour scale. Findings may well be different in other samples such as males. as external eating may be much more prevalent than emotional eating in males than in females (Van Strien, Frijters, Bergers, & Defares, 1986). In any event, the fact that emotional eating showed a significant relationship with emotional problems, but external eating did not, suggests that the two types of eating behaviors reflect independent constructs. This means that the Emotional and External Eating scales of the DEBQ measure theoretically different aspects of overeating (see also Van Strien, Frijters et al., 1986a; Van Strien, Rookus et al., 1986b). and continued use of both scales is warranted. One final caveat should be mentioned. In the present sample of female students and the subsamples who had problems with overeating, neither emotional eating nor external eating was significantly related to substance use problems (i.e., problems ‘Allison and Heshka (1993a) critical analysis of psychosomatic scale (Allison and Heshka, 1993b) will be discussed elsewhere. flawed (Van Strien, in press).
theory and the DEBQ Emotional Eating as their analysis seems to be seriously
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