Addictive Behaviors, Vol. 15, pp. 285-290, 1990 Printed in the USA. All rights reserved.
0306-4603/90 $3.00 + .00 Copyright © 1990 Pergamon Press plc
DIETARY RESTRAINT AND EATING BEHAVIOR IN THE NATURAL ENVIRONMENT W I L L I A M G. J O H N S O N , SHEILA A. C O R R I G A N , D A V I D G. SCHLUNDT, and P A T R I C I A M. D U B B E R T University of Mississippi Medical Center Abstract -- The influence of caloric labeling on meal selection with subjects differing in dietary restraint was investigated in a cafeteria restaurant. The three lowest calorie food selections within three food categories (i.e., salads, vegetables, entrees) were identified by labels. Within a multiple-baseline design, each food category was labeled for three evenings in a randomly determined order. Three hundred thirty-six male and female customers completed the Restraint Scale and were categorized as overweight or normal weight. Females and customers with high restraint scores chose and estimated that they chose lower calorie foods with neither effect for labeling nor a labeling-by-restraintinteraction evident. Customers high in restraint also underestimated the caloric values of their selections.
While the bulk of research on eating behavior has centered on physiological and metabolic variables, behavioral and cognitive factors are becoming increasingly prominent (Polivy & Herman, 1985; Rodin, 1981; Stunkard, 1980). An example of these latter influences on eating behavior is provided in the work of Herman and his colleagues who have introduced the construct of restraint to summarize research on the factors leading to the disinhibition of dieting (Herman & Mack, 1975; Herman & Polivy, 1975). Herman (1978) has developed and refined the Restraint Scale to measure the extent to which individuals are attempting to restrict their dietary intake. Research on restraint has been conducted in four areas: counterregulation, differential physiological responsivity of dieters versus nondieters, social-environmental influences on restrained eating, and psychometric properties of the Restraint Scale. Counterregulation is a fairly well established principle in which restrained eaters are observed to relinquish their diets after eating a high-calorie preload. In contrast, unrestrained eaters compensate for the preload by reducing their subsequent intake (Herman & Mack, 1975; Hibscher & Herman, 1977). Dieters also eat more when depressed or after drinking alcohol, whereas nondieters are not affected in this manner by negative moods and alcohol (Baucom & Aiken, 1981; Polivy & Herman, 1976a, 1976b). The interaction of cognitive and physiological variables is evident in other studies. For example, Spencer and Fremouw (1979) labeled the same preload as either high or low in calories. While unrestrained eaters behaved similarly under both conditions, restrained eaters ate much more after they believed they had eaten a high-calorie preload. Also, in two separate experiments, Klajner, Herman, Polivy, and Chhabra (1981) found that when presented with palatable food, dieters salivated more than nondieters regardless of their weight status. Social-environmental influences on eating appear to be more profound for dieters than nondieters. For example, Herman, Polivy, and Silver (1979) found that following a preload, restrained eaters maintained dietary control in the presence but not the absence of an observer, an effect not apparent for unrestrained eaters. Kirschenbaum and Tomarken (1982) Requests for reprints should be addressed to William G. Johnson, Ph.D., Dept. of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N. State Street, Jackson, MS 39216. 285
286
WILLIAMG. JOHNSONet al.
observed a similar phenomenon in attempts to develop regulatory as opposed to counterregulatory eating. Following a preload, restrained and unrestrained eaters were offered ice cream under four conditions: caloric label/large bowl, caloric label/small bowl, no caloric label/large bowl, and no caloric label/small bowl. Consistent with the counterregulatory effect, restrained eaters consumed significantly more ice cream than unrestrained eaters. The restrained eaters did, however, display regulatory eating in the caloric label/small bowl condition. More recently, Polivy, Herman, Hackett, and Kuleshnyk (1986) found that, following a preload, dietary restraint was enhanced by self- and experimenter observation. The present study is similar to Herman et al. (1979), Kirschenbaum and Tomarken (1982), and Polivy et al. (1986), in that variables which might enhance rather than disinhibit dietary control were investigated. In contrast, however, we attempted to influence dietary control in the natural environment as opposed to the laboratory setting. Our interest in the natural environment was dictated by a lingering question concerning the external validity of the Restraint Scale as virtually all studies have been conducted on undergraduates in laboratory settings (Johnson, Lake, & Mahan, 1983). Specifically then, we investigated the effect of caloric labeling on the caloric value of meals selected by individuals differing in restraint. According to restraint theory and the results of previous research, we expected that restrained eaters would select lower calorie meals compared to unrestrained eaters when the food was labeled. Conversely, when food was not labeled, we expected the restrained eaters to select higher calorie meals because of their presence in an attractive cafeteria setting. METHOD
Subjects Customers in a cafeteria restaurant were recruited as subjects over an 18-week period. After selecting their food and while taking their seat, every other adult customer was asked to participate in a study involving their food choices and attitudes towards eating. Of the 413 customers recruited as subjects, 226 (54.7%) were female and 187 (45.3%) were male. Eleven (2.5%) of the subjects were interviewed twice since they returned to the cafeteria within the 18-week period. No more than 14% of the total subject pool was interviewed in any given week. Two trained observers categorized each customer as overweight (at least 20% over ideal) or within a normal range. Only one subject could not be classified, since the observers disagreed on the categorization of this subject. Of the remaining 412 subjects, 81 (19.7%) were considered overweight with 331 (80.3%) thought to be within the normal range. These proportions of overweight and normals are similar to prevalence estimates in the adult U.S. population (National Center for Health Statistics, 1977). Interobserver agreement for these weight classifications on 60 randomly selected subjects was 94%.
Setting The study was conducted in a cafeteria restaurant located in a metropolitan area between a small business district and a residential community. The cafeteria has one serving line which is divided sequentially into sections for desserts, salads, vegetables, entrees, breads, and beverages.
Caloric labeling Consistent with our agreement with the cafeteria management, labels identifying the three lowest caloric selections within the three food categories (i.e., entrees, salads, and vegetables), rather than actual caloric values, were displayed. A dietician reviewed all recipes in the restaurant, measured serving sizes, and observed food preparation in order to
Eating behaviorin the natural environment
287
determine the caloric content of the servings. The labels were constructed of bright green poster paper (3 in x 2 in) with black lettering ("Lower Caloric Selection") and a bright red dot (3/4 in) in the upper right hand corner of the label to increase further the salience of the labels. Additionally, 17 in x 23 in green poster boards were placed near the cafeteria entrance at the beginning of the serving line to prompt subjects in the following manner: "For your information, we have labeled some lower calorie items. Watch for these signs." A sample identical to those on the labeled items was attached to these posters.
Procedure Observers were stationed at the cafeteria between 5:30-7:30 p.m. on 15 Tuesdays over an 18-week period. The observers approached the customers after they had selected their food to solicit their participation. After taking a seat, the observer asked the subjects if they had seen the labels (when present), and then asked them to name their food choices and estimate the caloric content of each item excluding drinks, soups, and breads. The Restraint Scale (Herman, 1978) was administered prior to eating and the subjects returned it to the observer as they left the cafeteria. The signs and labels were absent during baseline conditions. During the labeling conditions, the large signs were posted and the labels placed next to the food items. A multiple baseline design was used to determine the additive effect of labeling the lower calorie selections of the three food groups (e.g., salads, vegetables, entrees). A randomized order for labeling the food groups yielded the following sequence: baseline-l, label vegetables, label vegetables and salads, label vegetables, salads and entrees, and baseline-2. Each phase lasted for three evenings, totalling 15 sessions. RESULTS To evaluate the hypotheses, two variables were identified, namely, actual and estimated calories purchased. Actual calories purchased was defined as the sum of the caloric values for the items selected by each subject. Also, estimated calories purchased was defined as the sum of the subjects' estimates of the caloric content of items they had selected excluding breads, drinks, and soups. In order to limit the analyses to those customers who purchased full meals, 60 customers who purchased less than 250 calories or who estimated that they purchased less than 250 calories were dropped. Additionally, some caloric estimates were unrealistically high. Four customers who estimated that they purchased meals larger than 3000 calories were eliminated from the data set. An additional 12 subjects were dropped because they did not complete the Restraint Scale properly. The sample of 336 subjects remaining for analysis was not substantially different from the entire sample surveyed. Forty-six percent (N = 155) were male, and 54% (N = 181) were female, and 80% of the subjects were judged to be within the normal weight range for their heights.
Relationship of restraint with sex and overweight Chi-square tests were used to test for independence for bivariate distributions. Sex and restraint were significantly associated with females having higher restraint scores than males (X2) (1) = 16.0, p < .001). Likewise, weight and restraint were significantly associated with heavier subjects falling into the moderate and high restraint categories (X2) (1) = 44.2, p < .001). Relationship of restraint to actual calories purchased The actual calories purchased were analyzed using a general linear model approach with weight (normal vs. heavy), restraint scores,and labeling condition as the independent
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variables. There was a significant main effect for restraint, F(1, 335) = 4.68, p < .05. Customers with higher restraint scores tended to purchase lower calorie meals. There was no main effect for labeling, and no restraint by labeling interaction. The actual calories purchased were also analyzed with sex, restraint scores and labeling condition as the independent variables. There was a significant main effect for restraint, F( 1. 335) = 4.82, p < .05, as well as a significant main effect for sex with females purchasing lower calorie meals than males, F ( 1 , 3 3 5 ) = 8.69, p < .005. No other significant findings were obtained. Relationship o f restraint to estimated caloric values The subjects' estimates of calories purchased were analyzed using a general linear models approach with weight, restraint scores, and labeling condition as the independent variables. There was a significant main effect for restraint, F ( I , 335) = 12.76, p < .0005. Subjects with higher restraint scores gave lower caloric estimates of food purchased than subjects with lower restraint scores. There were no other significant main effects or interactions. When the subjects' estimated calories purchased were analyzed using sex, restraint, and labeling condition as the independent variables, significant main effects for restraint and sex were obtained. Subjects with higher restraint scores gave lower estimates of their caloric selection than subjects with lower restraint scores, F(1, 335) = 13.48, p < .0005. Females also estimated that they selected fewer calories than males, F(1, 335) = 14.67, p < .0005. However, females did in fact purchase lower calorie meals than male subjects. There were no other significant main effects or interactions. Relationship o f restraint to error scores An analysis of subjects' error scores (actual - estimated number of calories purchased) suggested that, overall, subjects tended to underestimate the number of calories they purchased. When restraint, weight, and labeling condition were entered as independent variables in a general linear models procedure, subjects with higher restraint scores tended to underestimate the number of calories purchased to a larger extent than subjects with lower restraint scores, F ( 1 , 3 3 5 ) = 2.71, p < . 10. There were no other significant main effects or interactions. While subjects with higher restraint scores did purchase fewer calories, the discrepancy between actual and estimated intake was greater for these subjects than for subjects with lower restraint scores.
DISCUSSION The present study sought to determine whether caloric labeling would influence food selections of individuals differing in dietary restraint. On the basis of restraint theory and prior research, we expected that subjects high in dietary restraint would be more responsive to social and environmental cues such as those provided in the labeling condition. Specifically, we reasoned that the caloric labels would sensitize restrained customers to their food selections as they went through the cafeteria line, and thereby influence them to exhibit behavior consistent with their expressed interest in dietary restraint. While those high in restraint actually purchased and estimated that they purchased lower calorie meals, the actual caloric and estimated caloric selections of restrained customers were no different whether the labels were present or absent. While restrained customers estimated that they purchased significantly fewer calories than unrestrained customers in accord with their actual selections, restrained eaters were also more likely to underestimate their caloric intake. Furthermore, discrepancies between actual and estimated calories purchased were relatively uniform over the labeling conditions.
Eating behavior in the natural environment
289
In previous laboratory studies (Kirschenbaum & Tomarken, 1982; Polivy et al., 1986), drawing attention to consumption enhanced dietary restraint. While we fully expected that labeling would serve a similar function, no such effect was found. The failure of the labeling effect to influence behavior cannot be attributed to an ignorance o f the presence of the labels nor a limited number o f low calorie items. All subjects reported seeing the labels and could identify the lower calorie items within the three food categories. Perhaps the effect of labeling was offset by the influence of eating in the natural environment and contact with attractively presented food. Alternatively, like subjects in the Polivy et al. (1986) study, our customers' selections may have been influenced by social cues, such as the presence of other patrons and the cafeteria staff. The finding that subjects high in restraint were more likely to underestimate their caloric selections is congruent with the literature on the role of cognitions in the regulation of food intake (Polivy & Herman, 1985). Accordingly, subjects who considered themselves dieters (high restraint) maintained this self-perception by practicing dietary restraint in choosing lower calorie selections. These subjects also engaged in a degree of self-deception as they significantly underestimated the caloric value of their food selections. A third possibility for the failure of the labels to differentially affect food selection among restrained eaters is that dieters are already aware of the caloric content of food items in the natural environment. Unlike the laboratory setting where labels can serve to identify caloric values of more ambiguous food items, calorie-conscious dieters are able to estimate the caloric value of food in the natural environment based upon prior experience. Although labeling food selections as low calorie did not differentially affect low versus high restraint subjects, the observation that restrained eaters uniformly purchased and estimated that they purchased fewer calories than subjects with low restraint scores can be taken as evidence supporting the external validity of the Restraint Scale. Further research using more objective estimates of food intake is necessary.
REFERENCES Baucom, D.H., & Aiken, P.A. (1981). Effect of depressed mood on eating among obese and nonobese dieting and nondieting persons. Journal of Personality and Social Psychology, 41,577-585. Herman, C.P. (1978). Restrained eating. In A.J. Stunkard (Ed.), The psychiatric clinics of North America (pp. 593-607). Philadelphia: Saunders. Herman, C.P., & Mack, D. (1975). Restrained and unrestrained eating. Journal of Personality, 43, 647-660. Herman, C.P., & Polivy, J. (1975). Anxiety, restraint, and eating behavior. Journal of Abnormal Psychology, 84, 666-672. Herman, C.P., Polivy, J., & Silver, R. (1979). Effects of an observer on eating behavior. The induction of "sensible" eating. Journal of Personality, 47, 85-99. Hibscher, J.A., & Herman, C.P. (1977). Obesity, dieting, and the expression of "obese" characteristics. Journal of Comparative and Physiological Psychology, 91,374-380. Johnson, W.G., Lake, L., & Mahan, J.M. (1983). Restrained eating: Measuring an elusive construct. Addictive Behaviors, 8, 413-418. Kirschenbaum, D.S., & Tomarken, A.J. (1982). Some antecedents of regulatory eating by restrained and unrestrained eaters. Journal of Abnormal Psychology, 91, 326-336. Klajner, F., Herman, C.P., Polivy, J. & Chhabra, R. (1981). Human obesity, dieting, and anticipating salivation to food. Physiology and Behavior, 27, 195-198. National Center for Health Statistics. (1977). Weight by height and age of adults 18-74 years: United States, 1971-1974. Vital and Health Statistics Advance Data No. 14. Polivy, J., & Herman, C.P. (1967a). Clinical depression and weight change: A complex relation. Journal of Abnormal Psychology, 85, 338-340. Polivy, J., & Herman, C.P. (1976b). Effects of alcohol on eating behavior: Disinhibition or sedation? Addictive Behaviors, 1, 121-125. Polivy, J., & Herman, C.P. (1985). Dieting and binging: A causal analysis. American Psychologist, 40, 193-201. Polivy, J., Herman, C.P., Hackett, R., & Kuleshnyk, I. (1986). The effects of self-attention and public attention on eating in restrained and unrestrained subjects. Journal of Personality and Social Psychology, 6, 1253-1260.
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Rodin, J. (1981). Current status of the internal-external hypothesis for obesity. American Psychologist, 36, 361-372. Spencer, J.A., & Fremouw, W.J. (1979). Binge eating as a function of restraint and weight classification. Journal of Abnormal Psychology, 88, 262-267. Stunkard, A.J. (1980). Obesity. Philadelphia: W.B. Saunders.
0306-4603/90 $3.00 + .00 Copyright © 1990 Pergamon Press plc
DIETARY RESTRAINT AND EATING BEHAVIOR IN THE NATURAL ENVIRONMENT W I L L I A M G. J O H N S O N , SHEILA A. C O R R I G A N , D A V I D G. SCHLUNDT, and P A T R I C I A M. D U B B E R T University of Mississippi Medical Center Abstract -- The influence of caloric labeling on meal selection with subjects differing in dietary restraint was investigated in a cafeteria restaurant. The three lowest calorie food selections within three food categories (i.e., salads, vegetables, entrees) were identified by labels. Within a multiple-baseline design, each food category was labeled for three evenings in a randomly determined order. Three hundred thirty-six male and female customers completed the Restraint Scale and were categorized as overweight or normal weight. Females and customers with high restraint scores chose and estimated that they chose lower calorie foods with neither effect for labeling nor a labeling-by-restraintinteraction evident. Customers high in restraint also underestimated the caloric values of their selections.
While the bulk of research on eating behavior has centered on physiological and metabolic variables, behavioral and cognitive factors are becoming increasingly prominent (Polivy & Herman, 1985; Rodin, 1981; Stunkard, 1980). An example of these latter influences on eating behavior is provided in the work of Herman and his colleagues who have introduced the construct of restraint to summarize research on the factors leading to the disinhibition of dieting (Herman & Mack, 1975; Herman & Polivy, 1975). Herman (1978) has developed and refined the Restraint Scale to measure the extent to which individuals are attempting to restrict their dietary intake. Research on restraint has been conducted in four areas: counterregulation, differential physiological responsivity of dieters versus nondieters, social-environmental influences on restrained eating, and psychometric properties of the Restraint Scale. Counterregulation is a fairly well established principle in which restrained eaters are observed to relinquish their diets after eating a high-calorie preload. In contrast, unrestrained eaters compensate for the preload by reducing their subsequent intake (Herman & Mack, 1975; Hibscher & Herman, 1977). Dieters also eat more when depressed or after drinking alcohol, whereas nondieters are not affected in this manner by negative moods and alcohol (Baucom & Aiken, 1981; Polivy & Herman, 1976a, 1976b). The interaction of cognitive and physiological variables is evident in other studies. For example, Spencer and Fremouw (1979) labeled the same preload as either high or low in calories. While unrestrained eaters behaved similarly under both conditions, restrained eaters ate much more after they believed they had eaten a high-calorie preload. Also, in two separate experiments, Klajner, Herman, Polivy, and Chhabra (1981) found that when presented with palatable food, dieters salivated more than nondieters regardless of their weight status. Social-environmental influences on eating appear to be more profound for dieters than nondieters. For example, Herman, Polivy, and Silver (1979) found that following a preload, restrained eaters maintained dietary control in the presence but not the absence of an observer, an effect not apparent for unrestrained eaters. Kirschenbaum and Tomarken (1982) Requests for reprints should be addressed to William G. Johnson, Ph.D., Dept. of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N. State Street, Jackson, MS 39216. 285
286
WILLIAMG. JOHNSONet al.
observed a similar phenomenon in attempts to develop regulatory as opposed to counterregulatory eating. Following a preload, restrained and unrestrained eaters were offered ice cream under four conditions: caloric label/large bowl, caloric label/small bowl, no caloric label/large bowl, and no caloric label/small bowl. Consistent with the counterregulatory effect, restrained eaters consumed significantly more ice cream than unrestrained eaters. The restrained eaters did, however, display regulatory eating in the caloric label/small bowl condition. More recently, Polivy, Herman, Hackett, and Kuleshnyk (1986) found that, following a preload, dietary restraint was enhanced by self- and experimenter observation. The present study is similar to Herman et al. (1979), Kirschenbaum and Tomarken (1982), and Polivy et al. (1986), in that variables which might enhance rather than disinhibit dietary control were investigated. In contrast, however, we attempted to influence dietary control in the natural environment as opposed to the laboratory setting. Our interest in the natural environment was dictated by a lingering question concerning the external validity of the Restraint Scale as virtually all studies have been conducted on undergraduates in laboratory settings (Johnson, Lake, & Mahan, 1983). Specifically then, we investigated the effect of caloric labeling on the caloric value of meals selected by individuals differing in restraint. According to restraint theory and the results of previous research, we expected that restrained eaters would select lower calorie meals compared to unrestrained eaters when the food was labeled. Conversely, when food was not labeled, we expected the restrained eaters to select higher calorie meals because of their presence in an attractive cafeteria setting. METHOD
Subjects Customers in a cafeteria restaurant were recruited as subjects over an 18-week period. After selecting their food and while taking their seat, every other adult customer was asked to participate in a study involving their food choices and attitudes towards eating. Of the 413 customers recruited as subjects, 226 (54.7%) were female and 187 (45.3%) were male. Eleven (2.5%) of the subjects were interviewed twice since they returned to the cafeteria within the 18-week period. No more than 14% of the total subject pool was interviewed in any given week. Two trained observers categorized each customer as overweight (at least 20% over ideal) or within a normal range. Only one subject could not be classified, since the observers disagreed on the categorization of this subject. Of the remaining 412 subjects, 81 (19.7%) were considered overweight with 331 (80.3%) thought to be within the normal range. These proportions of overweight and normals are similar to prevalence estimates in the adult U.S. population (National Center for Health Statistics, 1977). Interobserver agreement for these weight classifications on 60 randomly selected subjects was 94%.
Setting The study was conducted in a cafeteria restaurant located in a metropolitan area between a small business district and a residential community. The cafeteria has one serving line which is divided sequentially into sections for desserts, salads, vegetables, entrees, breads, and beverages.
Caloric labeling Consistent with our agreement with the cafeteria management, labels identifying the three lowest caloric selections within the three food categories (i.e., entrees, salads, and vegetables), rather than actual caloric values, were displayed. A dietician reviewed all recipes in the restaurant, measured serving sizes, and observed food preparation in order to
Eating behaviorin the natural environment
287
determine the caloric content of the servings. The labels were constructed of bright green poster paper (3 in x 2 in) with black lettering ("Lower Caloric Selection") and a bright red dot (3/4 in) in the upper right hand corner of the label to increase further the salience of the labels. Additionally, 17 in x 23 in green poster boards were placed near the cafeteria entrance at the beginning of the serving line to prompt subjects in the following manner: "For your information, we have labeled some lower calorie items. Watch for these signs." A sample identical to those on the labeled items was attached to these posters.
Procedure Observers were stationed at the cafeteria between 5:30-7:30 p.m. on 15 Tuesdays over an 18-week period. The observers approached the customers after they had selected their food to solicit their participation. After taking a seat, the observer asked the subjects if they had seen the labels (when present), and then asked them to name their food choices and estimate the caloric content of each item excluding drinks, soups, and breads. The Restraint Scale (Herman, 1978) was administered prior to eating and the subjects returned it to the observer as they left the cafeteria. The signs and labels were absent during baseline conditions. During the labeling conditions, the large signs were posted and the labels placed next to the food items. A multiple baseline design was used to determine the additive effect of labeling the lower calorie selections of the three food groups (e.g., salads, vegetables, entrees). A randomized order for labeling the food groups yielded the following sequence: baseline-l, label vegetables, label vegetables and salads, label vegetables, salads and entrees, and baseline-2. Each phase lasted for three evenings, totalling 15 sessions. RESULTS To evaluate the hypotheses, two variables were identified, namely, actual and estimated calories purchased. Actual calories purchased was defined as the sum of the caloric values for the items selected by each subject. Also, estimated calories purchased was defined as the sum of the subjects' estimates of the caloric content of items they had selected excluding breads, drinks, and soups. In order to limit the analyses to those customers who purchased full meals, 60 customers who purchased less than 250 calories or who estimated that they purchased less than 250 calories were dropped. Additionally, some caloric estimates were unrealistically high. Four customers who estimated that they purchased meals larger than 3000 calories were eliminated from the data set. An additional 12 subjects were dropped because they did not complete the Restraint Scale properly. The sample of 336 subjects remaining for analysis was not substantially different from the entire sample surveyed. Forty-six percent (N = 155) were male, and 54% (N = 181) were female, and 80% of the subjects were judged to be within the normal weight range for their heights.
Relationship of restraint with sex and overweight Chi-square tests were used to test for independence for bivariate distributions. Sex and restraint were significantly associated with females having higher restraint scores than males (X2) (1) = 16.0, p < .001). Likewise, weight and restraint were significantly associated with heavier subjects falling into the moderate and high restraint categories (X2) (1) = 44.2, p < .001). Relationship of restraint to actual calories purchased The actual calories purchased were analyzed using a general linear model approach with weight (normal vs. heavy), restraint scores,and labeling condition as the independent
288
WILLIAMG. JOHNSON et al.
variables. There was a significant main effect for restraint, F(1, 335) = 4.68, p < .05. Customers with higher restraint scores tended to purchase lower calorie meals. There was no main effect for labeling, and no restraint by labeling interaction. The actual calories purchased were also analyzed with sex, restraint scores and labeling condition as the independent variables. There was a significant main effect for restraint, F( 1. 335) = 4.82, p < .05, as well as a significant main effect for sex with females purchasing lower calorie meals than males, F ( 1 , 3 3 5 ) = 8.69, p < .005. No other significant findings were obtained. Relationship o f restraint to estimated caloric values The subjects' estimates of calories purchased were analyzed using a general linear models approach with weight, restraint scores, and labeling condition as the independent variables. There was a significant main effect for restraint, F ( I , 335) = 12.76, p < .0005. Subjects with higher restraint scores gave lower caloric estimates of food purchased than subjects with lower restraint scores. There were no other significant main effects or interactions. When the subjects' estimated calories purchased were analyzed using sex, restraint, and labeling condition as the independent variables, significant main effects for restraint and sex were obtained. Subjects with higher restraint scores gave lower estimates of their caloric selection than subjects with lower restraint scores, F(1, 335) = 13.48, p < .0005. Females also estimated that they selected fewer calories than males, F(1, 335) = 14.67, p < .0005. However, females did in fact purchase lower calorie meals than male subjects. There were no other significant main effects or interactions. Relationship o f restraint to error scores An analysis of subjects' error scores (actual - estimated number of calories purchased) suggested that, overall, subjects tended to underestimate the number of calories they purchased. When restraint, weight, and labeling condition were entered as independent variables in a general linear models procedure, subjects with higher restraint scores tended to underestimate the number of calories purchased to a larger extent than subjects with lower restraint scores, F ( 1 , 3 3 5 ) = 2.71, p < . 10. There were no other significant main effects or interactions. While subjects with higher restraint scores did purchase fewer calories, the discrepancy between actual and estimated intake was greater for these subjects than for subjects with lower restraint scores.
DISCUSSION The present study sought to determine whether caloric labeling would influence food selections of individuals differing in dietary restraint. On the basis of restraint theory and prior research, we expected that subjects high in dietary restraint would be more responsive to social and environmental cues such as those provided in the labeling condition. Specifically, we reasoned that the caloric labels would sensitize restrained customers to their food selections as they went through the cafeteria line, and thereby influence them to exhibit behavior consistent with their expressed interest in dietary restraint. While those high in restraint actually purchased and estimated that they purchased lower calorie meals, the actual caloric and estimated caloric selections of restrained customers were no different whether the labels were present or absent. While restrained customers estimated that they purchased significantly fewer calories than unrestrained customers in accord with their actual selections, restrained eaters were also more likely to underestimate their caloric intake. Furthermore, discrepancies between actual and estimated calories purchased were relatively uniform over the labeling conditions.
Eating behavior in the natural environment
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In previous laboratory studies (Kirschenbaum & Tomarken, 1982; Polivy et al., 1986), drawing attention to consumption enhanced dietary restraint. While we fully expected that labeling would serve a similar function, no such effect was found. The failure of the labeling effect to influence behavior cannot be attributed to an ignorance o f the presence of the labels nor a limited number o f low calorie items. All subjects reported seeing the labels and could identify the lower calorie items within the three food categories. Perhaps the effect of labeling was offset by the influence of eating in the natural environment and contact with attractively presented food. Alternatively, like subjects in the Polivy et al. (1986) study, our customers' selections may have been influenced by social cues, such as the presence of other patrons and the cafeteria staff. The finding that subjects high in restraint were more likely to underestimate their caloric selections is congruent with the literature on the role of cognitions in the regulation of food intake (Polivy & Herman, 1985). Accordingly, subjects who considered themselves dieters (high restraint) maintained this self-perception by practicing dietary restraint in choosing lower calorie selections. These subjects also engaged in a degree of self-deception as they significantly underestimated the caloric value of their food selections. A third possibility for the failure of the labels to differentially affect food selection among restrained eaters is that dieters are already aware of the caloric content of food items in the natural environment. Unlike the laboratory setting where labels can serve to identify caloric values of more ambiguous food items, calorie-conscious dieters are able to estimate the caloric value of food in the natural environment based upon prior experience. Although labeling food selections as low calorie did not differentially affect low versus high restraint subjects, the observation that restrained eaters uniformly purchased and estimated that they purchased fewer calories than subjects with low restraint scores can be taken as evidence supporting the external validity of the Restraint Scale. Further research using more objective estimates of food intake is necessary.
REFERENCES Baucom, D.H., & Aiken, P.A. (1981). Effect of depressed mood on eating among obese and nonobese dieting and nondieting persons. Journal of Personality and Social Psychology, 41,577-585. Herman, C.P. (1978). Restrained eating. In A.J. Stunkard (Ed.), The psychiatric clinics of North America (pp. 593-607). Philadelphia: Saunders. Herman, C.P., & Mack, D. (1975). Restrained and unrestrained eating. Journal of Personality, 43, 647-660. Herman, C.P., & Polivy, J. (1975). Anxiety, restraint, and eating behavior. Journal of Abnormal Psychology, 84, 666-672. Herman, C.P., Polivy, J., & Silver, R. (1979). Effects of an observer on eating behavior. The induction of "sensible" eating. Journal of Personality, 47, 85-99. Hibscher, J.A., & Herman, C.P. (1977). Obesity, dieting, and the expression of "obese" characteristics. Journal of Comparative and Physiological Psychology, 91,374-380. Johnson, W.G., Lake, L., & Mahan, J.M. (1983). Restrained eating: Measuring an elusive construct. Addictive Behaviors, 8, 413-418. Kirschenbaum, D.S., & Tomarken, A.J. (1982). Some antecedents of regulatory eating by restrained and unrestrained eaters. Journal of Abnormal Psychology, 91, 326-336. Klajner, F., Herman, C.P., Polivy, J. & Chhabra, R. (1981). Human obesity, dieting, and anticipating salivation to food. Physiology and Behavior, 27, 195-198. National Center for Health Statistics. (1977). Weight by height and age of adults 18-74 years: United States, 1971-1974. Vital and Health Statistics Advance Data No. 14. Polivy, J., & Herman, C.P. (1967a). Clinical depression and weight change: A complex relation. Journal of Abnormal Psychology, 85, 338-340. Polivy, J., & Herman, C.P. (1976b). Effects of alcohol on eating behavior: Disinhibition or sedation? Addictive Behaviors, 1, 121-125. Polivy, J., & Herman, C.P. (1985). Dieting and binging: A causal analysis. American Psychologist, 40, 193-201. Polivy, J., Herman, C.P., Hackett, R., & Kuleshnyk, I. (1986). The effects of self-attention and public attention on eating in restrained and unrestrained subjects. Journal of Personality and Social Psychology, 6, 1253-1260.
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