27British Journa/ of Hea/th Psych%gy (1998), 3, 27-40 Printed in Great Britain

@ 1998 The British Psychological Society

Brigitte Boon *, Wolfgang Stroebe and Henk SchutDepartment of Social and Organizational Psychology, Utrecht University, PO Box 80.140,

3508 TC Utrecht, The Netherlands

Anita JansenDepartment ofPsychology, Maastricht University, PO Box 616,6200 MD Maastricht,

The Netherlands

Objectives. Two studies examined the cognitive regulation of restrained eaters'eating behaviour. It was hypothesized that restrained dieters should have morerestraint-related cognitions in the presence of food stimuli than unrestrained eaters,whereas restrained non-dieters should occupy an intermediate position. The correlationbetween cognition and consumption should he zero fot unrestrained eaters and negativefot restrained eaters.

Design. Participants currencly dieting or not dieting and of high or low restraintstatus (median split) were presented in Study 1 with high and low calorie food wordsand asked to list their thoughts. In Study 2, participants listed thoughts following ataste test. In bath studies dief and restraint status were related to restraint relevantthoughts. In Study 2 thoughts were also related to actual consumption.

Methods. Participants werf female students; restraint status was measured with theRestraint Scale; current diet status was assessed with one question. Fifty-two unre-strained eaters, 38 restrained non-dieters and 18 restrained dieters participated inStudy 1; 33 unrestrained eaters, 19 restrained non-dieters and 11 restrained dietersparricipated in Study 2.

Results. Food stimuli elicited more eating control, weight- and shape-relatedthoughts in restrained dieters than in unrestrained eaters, with the restrained non-weters occupying an inteffi1ewate position. Consistent with predictions, the cognition-consumption correlation was zero fot unrestrained eaters and negative (trend) fotrestrained dieters. Contrary to prediction, this correlation was positive fot restrainednon-dieters.

Conclusions. Results show that cognitions play an important role in the regulationof the eating behaviour of restrained individuals. They further suggest that thecognitive regulation of food intake in restrained eaters maf be based on differentmechanisms in dieters as compared to non-dieters.

*ReQuests for reprints.

Brigitte Boon et al28

One of the major postulates of the boundary model for the regulation of eating states thatas soon as restrained eaters trangress their self-installed cognitive dier boundary,disinhibitive cognitions will lead to overeating (Herman & Polivy, 1984). A typicalexample of a disinhibitive cognition is the thought 'I've blown my dier, now I might asweIl continue to eat' (the 'what-the-hell effect', Herman & Polivy, 1984, pp. 150-151).Indeed, restrained eaters were found to eat more than unrestrained eaters af ter they hadconsumed a high caloric preload of rood which supposedly had induced them totransgress their dier boundary (for an overview see Ruderman, 1986).

Underlying this postulate seems to be the more general assumption that restrainedeaters reguiate their eating behaviour cognitively, regardless of whether or not theytransgress their dier boundary. Empirical support for the latter assumption is provided byvarious studies which indicate that restrained eaters can be induced to overeat by factorsother than the actual transgression of their dier boundary, e.g. the perception of havingeaten a high caloric preload regardless of the actual caloric content of the preload (e.g.Spencer & Fremouw, 1979; Woody, Constanzo, Liefer & Conger, 1981), the anticipationof high caloric rood (Knight & Boland, 1989; Ruderman, Belzer & Halperin, 1985;Tomarken & Kirschenbaum, 1984) or the experience ofnegative emotions (e.g. Baucom& Aiken, 1981; Cools, Schorre & McNally, 1992; Frost, Gooikasian, Ely & Blanchard,1982; Heatherton, Polivy, Herman & Baumeister, 1993; Polivy, Herman & McFarlane,1994; Schotte, Cools & McNally, 1990; Wardie & Beales, 1988).

Clinical findings support the assumption that thoughts or cognitions play animportant role in the eating behaviour of eating disordered patients. Individuals witheating disorders are known to be mentally focused on rood, weight and shape (Herman &Polivy, 1993). Bonifazi & Crowther, 1996; Zotter & Crowther 1991) reported empiricalevidence demonstrating that bulimics had relatively more eating- and weight-relatedthoughts than non-eating-disordered controls. Cooper & Fairburn (1992) reportedcompared findings. They had participants think aloud while looking at themselves ina fuli-iength mirror, weighing themselves, and eating a chocolate-covered mint. Patientswith eating disorders were found to have more negative thoughts related to eating,weight and shape than non-dieting controls, while dieting groups appeared to occupy anintermediate position.

Much less is known, however, about the precise role that cognitions play in influencingthe eating behaviour of restrained eaters. Several studies used indirect measures ofcognitions (e.g. King, Polivy & Herman, 1991; Ogden & Greville, 1993; Ogden &Wardie, 1991; Storland, Zuroff & Roy, 1991). Ogden & Wardie (1991) and Ogden &Greville (1993) measured cognitive states that represented thoughts related to surrender-ing to drives or reacting against self-constraints. They reported that restrained eatersscored higher on ratings of rebelliousness than unrestrained eaters. Storland et al. (1991)reported that restrained eaters spent more time thinking about their dier whileperforming a taste test than unrestrained eaters, and King et al. (1991) found thatrestrained eaters displayed a significanrly better recall for weight and rood items thanunrestrained eaters.

Recenrly, Bonifazi & Crowther (1996) used a newly constmcted Bulimic CognitionInventory as a war of measuring cognitions in real-life settings. Their bulimic, restrainedand control participants had to respond to this measure repeatedly according to a time-sampling schedule. They found that restrained eaters reported significantly more

Food lor thought 29

thoughts of weight and body image and low self-efficacy than the non-eating disorderedcontrol group, whereas they did not differ Erom the bulimic group. Bulimia andrestrained groups also rated their food and eating thoughts as more intense than thecontrol group.

To date, few studies have attempted to examine the exact content of restrained eaters'cognitions as compared to those of unrestrained eaters (Butow, Beumont & Touyz, 1993;French, 1992; Hickford, Ward & Bulik, 1997; Jansen, Merckelbach, Oosterlaan, Tuiten& Van den Hout, 1988) and only two of these have related these cognitions to actualeating behaviour, i.e. food intake in a taste test. Hickford et al. (1997) assessed cognitionsunder fasting and non-fasting conditions and reported no differences between restrainedand unrestrained eaters. Likewise Butow et al. (1993), who measured dysfunctionalcognitions, found no difference between restrained and unrestrained eaters. Jansen andcolleagues, who made the first attempt to measure cognitions directly in a 'think aloud ontape' task, did not report differences between restrained and unrestrained eaters (Jansenet al., 1988). French (1992) found that preloaded restrained eaters expressed morecontrol-related thoughts regarding food than non-preloaded restrained eaters andunrestrained eaters. However, these thoughts did not mediate disinhibited eating.

The present study bas therefore been designed to study eating-related cognitions ofrestrained and unrestrained eaters and to clarify the relationship between eatingcognitions and food intake. We hypothesized that the thoughts of restrained eaters inreaction to the presentation of food stimuli would differ Erom those of unrestrained eaters.Restrained eaters were expected to express more food, weight-, shape- and eating-control-related cognitions than unrestrained eaters. We further assumed that the thoughts ofrestrained but not of unrestrained eaters play an important fale in eliciting andcontrolling their eating behaviour. Or, as Herman & Polivy phrased it, '.. .cognitivepressures are demonstrably effective in influencing, if not absolutely controlling, eating'(1984, p. 144). Thoughts of the positive aspects of food ('eating this is good for myhealth') should be related to increased eating. Thoughts of the negative aspects of food('this contains many calories'), or diet/eating-control-related thoughts ('I have to keep mydier) should be related to decreased eating.

Preliminary evidence for the latter hypothesis bas been provided by Cooper, Clark &Fairburn (1993) who activated thoughts of eating, weight and shape in an experimentalgroup, but not in a con trol group. Their experimental group reported more negativethoughts following the experimental manipulation and ate less in the taste test than thecontrol group. Unfortunately, the authors give no information on the exact content of thethoughts ofboth groups, thus there was no direct evidence for Dur hypothesis that eating-control thoughts are related to decreased eating. Moreover, the study did not includegroups of restrained and unrestrained eaters.

Our participants were also categorized according to whether or not they were presentlydieting. The importance of assessing current diet status was suggested by the findings ofLowe and colleagues (Lowe, 1993, 1995; Lowe, Whitlow & Bellwoar, 1991) that counter-regulation after consuming a preload only appeared in restrained eaters not currently on adiet whereas restrained dieters ate most without a preload. These findings tend to suggestthat different cognitive mechanisms maf be at work for restrained dieters and restrainednon-dieters. We therefore hypothesized that restrained dieters would be most likely toshow the predicted negative correlation between the number of restraint-relevant

30 Brigitte Boon et al.

thoughts and the consumption of high caloric rood. Current dieters try to restrict theirrood intake, and since their rood intake is thought to be regulated cognitively, theirthoughts are aimed at eating little. They will manage to do so as long as their dietboundary is not transgressed and no negative emotions are induced. For restrained eaterswho are not cutrently dieting, a negative but less strong correlation between the numberof restraint-thoughts and consumption is expected.

In order to test these hypotheses a method was used which induced restrained (dietingas weIl as non-dieting) and unrestrained eaters to report their thoughts. Correlationalanalyses between individual rood intake and reported thoughts could then provideinformation about the relationship between amount of rood intake and eating-controlcognitions. It was decided to collect participants' thoughts by means of thought listings,based on the assumption that frequency of output reflects chronically accessible attitudes(see for example Bargh, Lombardi & Higgins, 1988; Higgins, King & Mavin, 1982).Chronically accessible constructs are assumed to develop Erom frequent and consistentdirect experience with aspecific domain of behaviour (Bargh et al., 1988; Fazio, Chen,McDonel & Sherman, 1982). Restrained eaters who frequently and consistently try tocon trol their rood intake and their weight, maf thus be expected to have highly accessiblerestraint- and weight-related constructs (e.g. 'I will gain weight if I eat this', 'Thiscontains too many calories', 'I am allowed to eat this', etc.). In contrast, unrestrainedeaters, who are not particulatly interested in fond- and weight-related matters, will notshow highly accessible constructs for these factors.

Chronic accessibiliry of constructs or attitudes cao be measured by confrontingparticipants with attitude-relevant objects (Bargh et al., 1988; Higgins et al., 1982).Thoughts elicited by rood stimuli should thus define which constructs are highlyaccessible in restrained eaters as compared to unrestrained eaters. The content of thesethoughts should then (if eating is cognitively controlled) determine how much rood theywill consume.

The present article describes two experiments. The first study tested the hypothesisthat restrained eaters-especially the cutrent dieters-had more accessible restraint- andweight-related constructs than unrestrained eaters. In this study, thoughts were elicitedby presenting participants with a series of rood words. Relative frequency of output wasconsidered to reflect the level of accessibility of constructs. The second experimentassessed thoughts elicited in an experimental eating situation. This situation also allowedus to assess the relationship between food-related thoughts and eating behaviour and totest the hypothesis that the content of restrained individuals' thoughts determines theamount they eat. In both studies participants were asked whether they were currently

dieting.

STUDY 1Method

P articiPants

Participants were 125 female psychology students who participared in workshops on eating behaviour. Thestudy was conducted in group sessions. The questionnaires of 10 participants were used to train independentjudges in raring the thoughts. The remaining 115 participants were categorized as restrained or unrestrained

Food for thought 31

eacers according co che median split score (11)1 on che Rescrainc Scale (RS). Parcicipancs scoring less chan 11

were classified as unrescrained eacers. Scorers above 11 were classified as rescrained eacers. Seven parcicipancsscored eaccly 11; chey were excluded from che analyses. Of out rescrained eacers (N = 56), 18 were currencly

diecing, whereas 38 were noc on a dier ac chac point in time. Table 1 shows che mean age, body mass index(BMI) and RS score of che rescrained diecers, rescrained non-diecers and unrescrained eacers.

Participant characteristics: StudyTable

AgeRS scoreBMIa

21.L7 .~

20.~

0.1151.2

4.6. BMI = body mass index = weight (kg)/height2 (m).

Procedure

At the beginning of the session, participants were given a form containing six food words (french fries, cake,cucumber, chocolate, apple and cheese sandwich). After reading eachfood word, they were asked to list thefirst five thoughts that occurred to them. Participants subsequently completed the Restraint Scale (Polivy,Herman & Warsh, 1978) used to categorize them as restrained or unrestrained eaters and some additionalquestions (about age, gender, weight, height). Current dier status was assessed by the question 'Are you on adier at this very moment?' Answer categories were 'no', 'a little', or 'yes'. Participants who answered a little oryes were considered to be current dieters. Participants were debriefed at the end of the session.

Materia/s

Thought listings. Thought listing was induced with the following instruction: 'Please write down, after everyfollowing word, the fitSt five thoughts that come inca fOUt mind'. Each of the six food words was displayed ona separate page.

Restraint Sca/e. The RS (Herman, Polivy & Warsh, 1978) is a 10-item questionnaire, designed to measure thelevel of eating restraint. It contains questions on dieting, concerns about weight and eating and weightvariation over different time periods. The RS is weIl validated (Ruderman & Besbeas, 1992) and widely usedto identify restrained and unrestrained eaters, for whom behaviour was successfully predicted in a series oflaboratory studies (for an overview, see e.g. Ruderman, 1986).

Results

Analysis of thoughtsBased on an overall inspection of the content of the thought listings, nine categories weregenerated in which each thought could be classified. To train two raters in classifying thethoughts, each blind to participants' RS scores, the thought listings of 10 participantswere first coded and discussed. The inter-rater agreement (Cohen's kappa; Cohen, 1960)

1 The median score for RS is lower in Out studies tban is usual in American research; however, this pattern is typical for the

research conducted in The Netherlands (e.g. Jansen et al., 1988).

l5)

!.O)

L.8)

.9)

.2)

.2)

Brigitte Boon et al.32

was .95. The data of these 10 participants were excluded from further analyses. The sametwo raters then, independently, coded each thought of 50 participants. This resulted in aCohen's kappa of .96, which indicated a satisfactory inter-rater agreement. The rest of thethought listings was rated by ODe of the two raters.

Table 2 shows the categories, examples and meao percentages of thoughts in eachcategory for unrestrained eaters, restrained non-dieters and restrained dieters. The Dillecategories are incorporated into three genera! categories 'restraint-relevant', 'restraint-irrelevant' and 'consumer-descriptive'.

Table 2. Categories, examples and mean percentages of thoughts in each category fot unrestrainedeaters, restrained non-dieters and restrained dieters: Study 1

16.44.0

10.12.2

9.62.15.71.7

I will become fat if I eat thisThis contains many caloriesI shouldn't eat toD much of this

Restraint relevantDiet or weightCaloriesRestraint, no dier or

weight mentioned

20.014.21.74.1

19.113.6

1.73.9

21.914.31.46.2

Consumer descriptiveLiking of the foodNot ijking of the foodInformation about

eating behaviour

I like french fries a lor

I bate cheeseI always eat chocolate when

drink coffee

71.315.59.4

46.5

61.812.710.638.5

71.614.8

11.545.3

Restraint irrelevant

Taste/appeacanceHealthMiscellaneous

An apple is round and sourCucurnbers are very healthyI just passed my exam

Restrained dieters vs. restrained non-dieters vs. unrestrained eaters

Inspection of the thoughts of restrained dieters, restrained non-dieters and unrestrainedeaters indicated that restrained dieters had most thoughts in the 'restraint-relevant'category while the unrestrained eaters had the smallest percentage of thoughts in thiscategory. A oDe-waf ANOVA revealed a main effect for restraint group (F (2,105) = 9.6,P < .001) and contrasts in a MANOVA showed that this difference was significant whenrestrained dieters were compared with either the unrestrained eaters (F(1,105) = 18.8,P < .001) or the restrained non-dieters (F(1,105) = 12.5, P < .005). The difference inrestraint-relevant thoughts between unrestrained eaters and restrained non-dieters was notsignificant (F(1,105) = 0.7, n.s.). The main effect for restraint group on the percentage ofthoughts in the genera! category 'restraint-relevant' was due to a main effect for restraintgroup in the subcategory 'calories' (F(2,105) = 9.8,p< .001), as weIl as to a main effect fotrestraint group in the subcategory 'dier or weight' (F(2,105) = 3.1,p < .05).

Since restrained individuals who were currently on a dier have somewhat higherrestraint scores than the restrained eaters not on a dier (Tabie 1), it is unclear whether the

Food lor thought 33

difference between these two groups should be attributed to differences in dieting statusor in restraint scores. We therefore conducted a oae-waf ANCOVA on restraint group,using restraint score as a covariate. This ANCOVA revealed a main effect for restraintgroup (F (2,104) = 4.0, P < .05) even with differences in restraint score statisticallycontrolled for, indicating that this effect was at least partly due to differential dietingstatus. This assumption was confirmed by the fact that the difference between restraineddieters and restrained non-dieters remained significant (F(1,104) = 6.10, P < .02),albeit with the F value halved from 12.5 to 6.10, when restraint score was used as acovariate in testing contrasts in a MANCOV A.

To be able to compare the thoughts elicited by fat food-words (french fries, cakeand chocolate) vs. non-fat food-words (apple and cucumber) in oae analysis, a 2 (fat/non-fat) X 3 (restraint) MANOVA with repeated measures was conducted with the percentageof thoughts in the category 'calories' as the dependent variabie. (The sixth word 'cheesesandwich' was not included in either the fat or non-fat food-words, since it can be definedas fat as weIl as non-fat.) The MANOVA revealed a main effect for restraint group(F(2,105) = 11.1, P < .001), as weIl as a main effect for fatness of the word(F(1,105) = 139.3, P < .001), the latter indicating that the fat words elicited morethoughts in this category than the non-fat words. There was no restraint X wordinteraction effect (F(2,105) = 1.4, n.s.). The MANOVA with repeatedmeasures was alsoconducted with the percentage of thoughts in the category 'diet or weight' as thedependent variabie. Again the analysis revealed a main effect for restraint group(F(2,105) = 3.1, P < .05), a main effect for word (F(1,105) = 11.3, P < .01) and nointeraction (F(2,105) = 0.9, n.s.). There were also no indications ofinteractions whenthese analyses were repeated on restrained individuals only, using 'fatness' and 'dietarystatus' as factors.

Discussion

As expected, restrained dieters expressed more eating-control, weight- and shape-relatedthoughts than unrestrained eaters, with the restrained non-dieters occupying an inter-mediate position. This pattern was particularly evident for the category 'calories'. Becausethe relative frequency of output is an accepted indicator of accessibility (e.g. Bargh et a/.,1988), it cao be concluded from these findings that the constmcts of restrained eatersabout calories and other restraint relevant attitudes are more accessible than those ofunrestrained eaters.

The findings also showed that this effect was almost exclusively due to restrained eaterswho were currencly dieting. Restrained eaters not on a dier did not differ very markedlyfrom unrestrained eaters. Although the substantial difference in restraint-relevantthoughts observed between restrained dieters and non-dieters cao be partly attributedto the relatively higher restraint scores of the restraint dieters, the fact that the differencebetween these two groups remained significant (albeit with a reduced F value), even withdifferences in restraint scores statistically controlled for, indicates that dietary status is anindependent contributory factor. This suggests that we are dealing with a combination ofchronic and acute (hunger-related) accessibility.

Thus, Dur finding that restrained eaters had more thoughts relating to eating controlrhan lmrestrained eaters is in line with the assumPtion underlvinf!. the boundary model

34 Brigitte Boon et al.

that restrained eaters regulate their eating behaviour cognitively. However, the fact thatthere was no interaction between restraint group and the calorie content of the food towhich the words referred (i.e. references to high as compared to low caloric food resultedin the same increase in restraint-related thoughts in unrestrained as in restrained eaters)suggests that cues to calorie content are attended to by bath groups. These findingstherefore raise a second and even more important question, namely whether thesethoughts about eating control are in fact related to eating behaviour. This hypothesiswas tested in Study 2.

STUDY 2Method

This study examined both the quantity of restraint-relevant thoughts produced in an experimental eatingsituation and the fale of thoughts in controlling participants' consumption of high caloric food.2

P articiPants

Participants were 70 female students from several schools and university departments in Utrecht who hadcompleted the RS as part of a questionnaire study conducted a month before the experiment and whoseweight was within the normal BMI range (self-report).

As in Study 1, participants were classified as restrained or unrestrained eaters by using the median splitmethod on the RS scores. Two participants did not fully complete the RS. For the remaining 68 participantsthe median score was 10. Five participants who scored exactly at the median were excluded from the analyses.Of our restrained eaters (N = 30), 11 reported that they were currently dieting, whereas 19 were not. Table 3presents the mean age, BMI and RS score of the restrained dieters, restrained non-dieters and unrestrainedparticipants.

Table 3. Participant characteristics: Study 2

U nrestrainedeaters

(N = 33)

Restrainednon-dieters(N=19)

M (SrnM (SD)

5 (2.1)~ (2.2)7 (1.6)

Restraineddieters

- -, (N= 11)

" <. -- ,--, M (SD)

(: 22.0 (2.0)(: 20.1 (4.4)

--- (: 23.0 (2.1)

F p

AgeRS scoreRMTa

22.516.223.5

0.7141.812.9

n.s..000.000. BMI = body mass index = weight (kg)/height2 (m).

Design and procedure

Participants perfotmed a taste test in which they were presented with three bowls of different peanuts (plainpeanuts, sugared peanuts and cocktail-Duts) each bowl containing approximately 1000 grams. They wereinstructed to taste at least ODe nut from each bowl and were told to feel free to eat as much as they wanted oras much as they needed fot reliable taste ratings. Participants were given separate taste rating forms fot each

2 The study was part of a latget study which also assessed the effects of positive and negative mood on eating behaviout.

Howevet ANOVAs indicated that mood did not affect the number of thoughts in different categories, nor did ir affectpanicipants' subsequent food intake. We thus collapsed our mood conditions to look at restrained and unresrrained eaters'thoughts and food intake independently of their mood.

-21.c5.1

20."

3.6)2.7)2.6)

35Food lor thought

type of nut and they were instructed to answer the questions after having tasted the outs. They were then leEr

alone for 10 minutes to do the test.After 10 minutes the experimenter rerurned and participants were given a farm on which they were asked

to list all the thoughts (maximum 10) they had had while performing the taste test. Finally, participants'height and weight were measured and they were debriefed, thanked and paid for participation. After theparticipants had leEr, their rood intake was measured (the bowls with outs were weighed before and after

participants performed the taste test).

Results

Analysis of thoughtsParticipants' thoughts were classified into the same categories as in our first study. Thesame two raters, again unaware of participants' restraint scores, independently coded thethoughts of all the participants. The inter-rater agreement, Cohen's kappa, was .93; againa satisfactory outcome. The meao percentages of thoughts in each category are presented

in Table 4.

Table 4. Categories and mean percentages of thoughts in each category for unrestrained eaters,restrained non-dieters and restrained dieters: Study 2

6.83.62.70.5

Restraint relevantDiet or weightCaloriesRestraint, no diet or

weight mentioned

18.59.15.14.3

Consumer descripriveLiking rhe roodNot ijking the roodInformation about

eating behaviour

18.613.23.91.6

10.75.62.62.6

68.010.40.0

57.6

78.510.80.0

67.7

82.510.80.6

71.1

Restraint irrelevant

Taste/appearanceHealthMiscellaneous

Restrained dieters vs. restrained non-dieters vs. unrestrained taters

An ANOVA, comparing restrained dieters with restrained non-dieters and unrestrainedeaters, revealed a main effect for the restraint group on the percentages of thoughts in the'restraint relevant' category (F (2,60) = 3.54, P < .05). Restrained dieters had the mostand unrestrained eaters the least number of restraint-relevant thoughts. Contrasts in aMANOVA showed that this difference was only significant when restrained dieters werecompared with the unrestrained eaters (F(1,60) = 6.9, P < .05). The differences in

36 Brigitte Boon et al.

restraint relevant thoughts between restrained dieters and restrained non-dieters(F(I,60) = 2.3, n.s.) or between the latter and unrestrained eaters (F(I,60) = 1.4,n.s.) were in the expected direction, but non-significant. The main effect fot restraintgroup on the percentages of thoughts in the general category 'restraint-relevant' was dueto a main effect fot restraint-group in the subcategory 'dier or weight' (F (2,60) = 5.6,P < .01).

As in Study 1, the analysis of the association of restraint relevant thoughts and restraintgroup was repeated using restraint score as a covariate to assess whether the differencesbetween dieters and non-dieters were due to their dieting status or to the differences intheir restraint scores. Unlike in Study 1, the main effect of restraint group on thepercentage of thoughts in the 'restraint-relevanr' category now disappeared(F(2,59) = 1.0, n.s.) due to the significant effect of the covariate (F(I,59) = 5.0,P < .05). Furthermore, the introduction of a covariate rendered the previously significantcontrast between restrained dieters and unrestrained eaters non-significant(F(I,59) = 1.38, n.s.).

Thoughts and Jood intake

Table 5 presents the mean consumption for the three groups as weIl as the correlationsbetween consumption and restraint-relevant thoughts. There were no significantdifferences in consumption between the three groups (F(2,60) = 1.3, n.s.), althoughthe dieters did eat somewhat more, which is typical for this group (Lowe, 1993). In linewith our predictions, no significant correlation was found between restraint-relevantthoughts and food intake for the unrestrained eaters. For the restrained eaters, the resultswere as expected if they were currently dieting, but contrary to expectations if they werenot currently dieting. Restrained eaters who were not currently dieting showed asignificant positive correlation between restraint relevant thoughts and food intake,whereas this correlation for the restrained dieters revealed a negative trend.3 Restrainednon-dieters appeared to eat more if they had more restraint-relevant thoughts. Restraineddieters showed a trend of eating less if they had more restraint-relevant thoughts. Thedifference between the two correlations, with the respective sample sizes taken intoaccount, is significant (z = 2.12, P < .014).

Table 5. Mean consumption and correlations with restraint-relevant thoughts: Study 2

Correlation withrestraint thoughtsConsumption in grams

41.8440.9557.11

Unrestrained eaters (N = 33)Restrained non-dieters (N = 19)Restrained dieters (N = 11)

.04

.47-.42

n.s..02 (one-tailed).10 (one-tailed)

3 The correlarions between cognition and consumption fot the restrained non-dieters and dietets rernain practically

unchanged (.50 and -.42) if restraint score is being partialied out.

Food lor thought 1,7

Discussion

Like exposure to food-words, the actual intake of high calorie food elicited a greaternumber of eating-control-, weight- and shape-related thoughts in restrained dieters thanin unrestrained eaters, with the restrained non-dieters occupying an intermediateposition. The fact that the patterns of thoughts elicited by exposure to food wordscould generally be replicated in an actual (albeit experimental) eating situation increasesour trust in the external validity of this relationship.

However, there are also same differences in the findings between the two studies,mainly concerning the association between dieting status and frequency of restraint-relevant thoughts. Although restrained dieters listed twice as many restraint-relevantthoughts as the restrained non-dieters, this difference failed to reach significance. Sincethe difference in average number of thoughts between the two groups is practicallyidentical to that observed in Study 1, we would tend to attribute the failure of thisdifferente to reach significance in the second study to reduced power, due to the smallernumber of participants in the experimental study.

Our findings concerning the relationship between restraint-relevant thoughts andamount eaten were only partly consistent with our hypotheses. In line with predictions,there was no relationship between restraint-relevant thoughts and consumption forunrestrained eaters. This is consistent with our assumption that unrestrained eaters donot engage in cognitive control of their eating behaviour. The negative correlationbetween restraint-relevant thoughts and eating behaviour predicted for the restrainedeaters was only observed for restrained individuals currently on a diet. Althoughdescriptively substantial, tbis correlation is only marginally significant, due to thesmall number of dieters who had participated in the second study. The restrained non-dieters, on the other hand, contrary to our predictions, displayed a significant positivecortelation between cognition and consumption.

Why do restrained eaters show these opposite patterns depending on their current dietstatus? Current dieters' explicit behavioural rule maf be an important aspect of theexplanation. When they are confronted with (eating) high caloric food, their diet mIe willimmediately become salient. Thoughts about calories and the effects of eating the foodwill cause them to limit their consumption. By contrast, among the restrained eaters whoare not currently dieting, such diet rules are not operational. It is possible that theabsence of explicit diet mIes in the restrained non-dieters causes an effect that restrainedeaters are afraid of, namely, the more they think about food, the more they eat. Herman &Polivy (1993) suggested that thoughts of food and eating represent a danger to restrainedeaters, since they presumably make it harder to refrain Erom eating. Explicit dietary rules,as in current dieters, maf prevent this effect. The design of our present experiments,however, does not allow further examination of this explanation.

It is worth noting that the correlations between thoughts and food intake were notaccompanied by group differences in average consumption. In fact, the only difference inconsumption to be observed was the typical finding (Lowe, 1993) that our dieters ateslightly more ice cream (16.16g) than the non-dieters. Although according to common-sense notions ODe might have expected differences in average consumption, with theunresttained eaters eating most and the restrained dieters eating least, such predictionsrannor he derived Erom the boundarv model. Af ter all. it is no coincidence that restrained

38 Brigitte Boon et al.

eaters try to restrain their eating: They have substantially higher BMI values than ourunrestrained participants. Although this could be due to differences in metabolismbetween these groups, it could also be due to differences in eating behaviour.Furthermore, the dieters probably suffered from acute hunger pangs whilst given theopportunity (and the permission) to feed on tasty ice cream. Thus it would be naÏve toassume that the average consumption of the unrestrained eaters reflects the baseline ofwhat restrained eaters would have eaten if they had not tried to restrain theirconsumption.

GENERAL DISCUSSION

The association observed between rood stimuli and cognitions in both studies isconsistent with our predictions: exposure to food-words as weIl as actual rood intakeelicited more eating-control-, weight- and shape-related thoughts in restrained eatersthan in unrestrained eaters, with restrained dieters reporting the highest number ofthoughts. These findings are supportive of our theoretical assumption that the experienceof repeatedly restraining one's rood intake to lose weight or keep one's weight downwould result in highly accessible restraint- and weight-related constructs for restrainedeaters. The findings for current dieting in both srudies suggest that these constructsbecome even more accessible if a restrained eater is currently dieting. The latter effect ismost probably a consequence of recent activation of these constructs in the current dieter.Recency of activation is assumed to give a construct relatively greater accessibility, atleast for a limited time period (Bargh et al., 1988).

Our findings concerning the relationship between cognition and consumption revealeda pattem which was more complicated than we had expected. They supported O\1chypothesis that restraint-relevant cognitions werf unrelated to consumption in ~nre-strained eaters but related in restrained eaters. However, contrary to our expectations, thelatter relationship was moderated by dieting starus. The finding that restraint-relevantcognitions facilitate eating control only for individuals who have formed the intention todier are in line with research on the attirude-behaviour relationship which generallyindicates that intentions mediate the relationship between attirude and behaviour (Ajzen,1988). They are also consistent with the research on goal-setting, which indicates thatsetting specific (and difficult) goals is much more effective in influencing behaviour thangiving general 'do your best' goals (Locke & Latham, 1990). They are finally supportive ofthe assumption undetlying the transtheoretical theory ofbehaviour change, that differentprocesses operate in the 'contemplation' and the 'action' stages (Prochaska, DiClemente &Norcross, 1992). Although not implied by these theories, the positive correlationbetween eating cognition and consumption observed in restrained eaters who have notyet formed the intention to go on a dier is also quite plausible. Whereas food-relatedcognitions are likely to remind the restrained dieters of their dieting rules, increasedthoughts about rood might stimulate increased eating in the absence of such dietingrules, even when these thoughts also refer to the negative consequences of eating.

AII in all, our findings indicate that the eating behaviour of restrained eaters is not inany simple war controlled by the number and content of their restraint cognitions. Theopposite directions of the correlations between restraint cognitions and rood intakedepending on dier status suggest different pathways along which behaviour maf be

39Food lor thought

related to cognitions in restrained eaters. These findings tend to emphasize that thepicture is more complex than implied by the boundary model, and that Lowe et al.'s(1991) distinction between the two kinds of restrained eaters is a valuable one. Studiesthat explore cognitions in restrained dieters and non-dieters in various situations areneeded to provide information on the nature of the congitive regulation. Studies in whichspecific cognitions are induced, or in which dietary rules are primed while palatabie foodis present, maf offer useful evidence on the congition-behaviour relationship in currentdieters versus non-dieters.

AcknowledgementsThe authors wish to thank Hennie Dings and Luka Geenen for their help in categorizing the thoughts.

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Received 1 May 1997; revised version received 22 AuJ(ust 1997