A new scale for use in non-clinical research into disinhibitive eating

Construct validation of the Portuguese version of the Restraint Scale

Aim

The main purpose of this study was to adapt the Restraint Scale (RS) to Portuguese and examine its psychometric properties, specifically its construct validity.

Method

In this study, 238 normal-weight adults (82% women; Mean age = 36.6, SD = 15.0) participated in an online survey containing measures of Restraint Scale, Three Factor Eating Questionnaire, Dutch Eating Behaviour Questionnaire, and Body Dissatisfaction and Drive for Thinness scales.

Results

Exploratory factor analyses corroborated the two-factors structure found in previous studies, in particular when three items without clear factorial assignment and low correlation were excluded. A final two-factors version of the RS containing seven items presented a very good fit to the measurement model and good internal consistency. Confirmatory factor analysis of the 7-items RS in relation to a three-factor model of overeating, dieting and body dissatisfaction measures revealed that the RS was the only restraint measure loading in all three factors.

Conclusion

This suggests that the 7-items Portuguese version of the RS has good psychometric properties and unique features that lend it appropriate to identify and study unsuccessful chronic dieters.

The discrepancy between implicit and explicit attitudes in predicting disinhibited eating

Disinhibited eating (i.e., the tendency to overeat, despite intentions not to do so, in the presence of palatable foods or other cues such as emotional stress) is strongly linked with obesity and appears to be associated with both implicit (automatic) and explicit (deliberative) food attitudes. Prior research suggests that a large discrepancy between implicit and explicit food attitudes may contribute to greater levels of disinhibited eating; however this theory has not been directly tested. The current study examined whether the discrepancy between implicit and explicit attitudes towards chocolate could predict both lab-based and self-reported disinhibited eating of chocolate. Results revealed that, whereas neither implicit nor explicit attitudes alone predicted disinhibited eating, absolute attitude discrepancy positively predicted chocolate consumption. Impulsivity moderated this effect, such that discrepancy was less predictive of disinhibited eating for those who exhibited lower levels of impulsivity. The results align with the meta-cognitive model to indicate that attitude discrepancy may be involved in overeating.

Assessment of dietary restraint: psychometric properties of the revised restraint scale in Hong Kong adolescents

BACKGROUND

The psychometric properties of the Revised Restraint Scale (RRS) have been well established in western populations but not in Chinese adolescents.

PURPOSE

This study investigated the psychometric properties of RRS and its validity in different subgroups for Hong Kong Chinese adolescents.

METHOD

In 2007, 909 Hong Kong students aged 12 to 18 years (55.3% boys) completed a questionnaire including demographic items, RRS, Eating Attitudes Test (EAT-26), and Motivation for Eating Scale (MFES)-physical. Moreover, subjects' height and weight were measured. To examine the factor structure of RRS, the whole sample was randomly split into two groups (sample 1: N=454 and sample 2: N=455) for exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), respectively. Convergent and discriminant validity of RRS were investigated by correlating the RRS with EAT-26 and MFES-physical. Multigroup CFA was conducted to test the three-factor model of RRS in different sex, age, and weight status subgroups.

RESULTS

Results of EFA for sample 1 revealed three strongly correlated factors for the RRS construct, and were supported by the CFA results in sample 2. Multigroup CFA further suggested that the three-factor model of RRS was stable across sex, age, and weight status subgroups.

CONCLUSIONS

A new three-factor model is proposed for Hong Kong adolescents in this study. In general, RRS is a reliable and valid measure of restrained eating for adolescents, regardless of sex, age, and weight status.

Implicit and explicit attitudes to high- and low-calorie food in females with different BMI status

The study compared implicit and explicit attitudes to three types of foods (high-calorie non-sweet HCNS, high-calorie sweet HCS and low-calorie LC) among females varying in BMI status. Eight three participants completed an affective priming task (implicit attitudes), followed by explicit rating of food images. The results of ANOVA showed a significant difference in implicit attitudes to different types of food, F(3,246)=3.90, p<.01 and the difference among BMI groups (F(6, 213)=2.15, p<.05). The implicit attitudes to HCS were positive in the healthy-weight and overweight groups but negative in obese; the reversed pattern was revealed in attitudes to HCNS. All groups showed negative implicit attitudes to LC foods. The ANOVA performed on explicit ratings revealed a significant effect of food type (F(3,213)=22.54, p<001) but no interaction between food type and BMI status. All participants rated HCNS significantly lower than HCS and LC foods. Our results indicate dissociation in implicit and explicit attitudes to foods among BMI groups, especially in attitudes to HCNS and HCS foods.

Construct validation of the Restraint Scale in normal-weight and overweight females

The Restraint Scale (RS) is a widely used measure to assess restrained eating. The purpose of this study was to examine the construct validity of the RS in a sample of normal-weight (n=349) and overweight (n=409) females using confirmatory factor analyses of the RS in relation to other measures for dieting, overeating and body dissatisfaction. Following Laessle et al. [(1989a). A comparison of the validity of three scales for the assessment of dietary restraint. Journal of Abnormal Psychology, 98, 504-507], we assumed a three-factor structure: (1) overeating and disinhibitory eating, (2) dieting and restriction of food intake, and (3) body dissatisfaction and drive for thinness. Analyses revealed that the RS loaded significantly on all three factors for both samples, confirming its multifactorial structure. However, the RS appears to capture these constructs differently in overweight and normal-weight females such that the RS may overestimate restraint in overweight individuals. This may explain the greater effectiveness of the RS in predicting counter-regulation in normal-weight than in overweight samples of dieters.

Recording of swallowing events using electromyography as a non-invasive measurement of salivation

The present study examined whether the measurement of swallowing activity by electromyography (EMG) provides a sensitive and valid method for the assessment of the amount of saliva secreted. Thirteen subjects tasted lemon juice and water, and smelled lasagna and hay, while the amount of saliva, measured with the aid of cotton dental rolls, was compared with the number of peaks in the EMG activity of the musculus digastricus. Swallowing indeed differentiated between the stimuli and the correlation between the number of swallows and the amount of saliva was significant. The present data suggest that monitoring the swallowing movement using EMG might be a sensitive, valid and reliable method for the measurement of salivary flow. The use is recommended for the measurement of salivation when a simple and non-invasive method is needed.

Cue reactivity to food- and body-related stimuli in restrained and unrestrained eaters

In the present study, psychophysiological cue reactivity was monitored in 11 restrained (nonclinical but disinhibitive) and 13 unrestrained (control) subjects. The cues consisted of slides depicting either personally "favourite" binge food items or the subject's own body. The parameters monitored included skin conductance, heart rate, startle eyeblink EMG, and facial (corrugator and zygomatic) EMG. Although for several parameters the expected main effect of slide type was found, no between-group differences in cue reactivity could be demonstrated. Several explanations of the present finding, as well as possible future directions for cue reactivity research, are discussed, with emphasis placed upon the role of classical conditioning in eating disorders.