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42 M. Craeynest et al. / Eating Behaviors 9 (2008) 41–51 research is necessary to investigate whether the underlying dynamics of the food and physical activity behaviour are affected by the treatment, and to what extent their change is related to weight loss and weight regain. Several characteristics have been found to be important predictors of weight loss in obese youngsters following treatment, under which baseline degree of overweight and the child's age (Braet, 2006). Further, an amount of theories have dealt with possible explaining psychological determinants, such as the learning history of the child and a heightened responsiveness to food cues (for a review, see Braet, 2005). From a healthy psychology perspective, attitudes towards food and exercise have been put forward as crucial factors in the development and maintenance of obesity (e.g., De Bourdeaudhuij et al., 2005; Dennison & Shepherd, 1995). In most studies, attitudes are asked directly, for instance using self-reports. Recently, however, it has been argued that their indirect assessment, by which cognitions are inferred from behaviour performance other than self-report, should have a better explanatory and predictive value because of two reasons (Greenwald et al., 2002). First, indirect measures should be more resistant for demand characteristics that often affect self-reports (see Schwarz, 1999). Second, indirect measures are supposed to catch cognitive automatic associations that guide spontaneous behaviour, and that can not easily be tapped by self-reports. The outcome of the indirect assessment of these associations is often called implicit cognitions. Implicit attitudes then are the measure of automatic associations between an attitude object and a certain valence (Greenwald et al., 2002). In the last decades, several indirect response time based paradigms have been constructed to assess implicit attitudes (for a review, see Fazio & Olson, 2003), amongst which the affective priming task (Fazio, Sanbonmatsu, Powell, & Kardes, 1986), the Implicit Association Task (IAT; Greenwald, McGhee, & Schwartz, 1998) and the Extrinsic Affective Simon Task (EAST; De Houwer, 2003). The core principle of these tasks is that implicit attitudes are inferred from the reaction time (and percentage of errors) performance on a computer sorting task. More specifically, it is assumed that response latencies will be shorter (and less errors will be made) when participants have to use the same response bottom to sort stimuli that carry the same valence (congruent stimuli; e.g., names of insects and negative nouns vs. names of flowers and positive nouns), than when the same response bottom has to be pressed for stimuli with an opposite valence (incongruent stimuli; e.g., names of insects and positive nouns vs. names of flowers and negative nouns). Implicit attitudes are calculated then by comparing the performance on the congruent stimuli with the performance on the incongruent stimuli. Indirect measures have been applied in several domains of clinical and health psychology (for a review, see Fazio & Olson, 2003). As described elsewhere (Craeynest et al., 2005), we used the EAST in a cross-sectional study investigating implicit food and exercise attitudes in children and adolescents with obesity at the beginning of an intensive treatment. Our results revealed a borderline significant effect, indicating that youngsters with obesity implicitly preferred both unhealthy and healthy food, whereas normal-weight controls evaluated them as neutral. No effects were found for physical activity. Longitudinal research investigating whether implicit food and physical activity cognitions in youth obesity change over a treatment period, and to what extent they are related to treatment success (i.e., weight loss or weight gain), is scarce. We only know of the study by Barton, Walker, Lambert, Gately, and Hill (2004) in which a sentence-completion questionnaire was used to investigate whether automatic exercise and food cognitions change over the course of a residential weight loss camp for adolescents with obesity. They found a reduction in negative and an increase in positive thoughts about exercise, but not in those about eating. Further, cognitive change was largely accounted for by the reduction in weight. This manuscript describes a longitudinal study in which implicit and self-reported food and exercise attitudes are assessed in youngsters with obesity during a six month inpatient treatment and at a one year follow up. Self-reported attitudes are assessed with a questionnaire; implicit attitudes are assessed with an EAST. Three main questions are addressed: First, do implicit and self-reported food and exercise attitudes change during an inpatient treatment for obesity? Second, to what extent does a change in these attitudes explain the variance in weight change during treatment? And third, to what extent does a change in these attitudes explain the variance in weight loss or regain at follow up? 2. Methods 2.1. Participants Participants were thirty-eight obese children and adolescents at the beginning of their hospitalization in 2002–2003 in a medical-paediatric centre (MPC) that is specialized in the treatment of youth obesity. Fourteen of them dropped out
during the therapy because of having reached their therapy goal (n =4) or because of suspension due to behavioural problems breaking the rules of the centre such as smoking (n=10). Five could not be contacted at follow up. These youngsters did not differ from the rest of the group in terms of gender, χ 2 b1, and baseline overweight, tb1. Both groups differed in age, t(36) =2.12, p b.05: The mean age of the dropout group was higher (M=14.53, SD=2.37) than the mean age of the study group. Data were analyzed on this restricted group of nineteen youngsters, representing 50% of the original sample that was tested in Craeynest et al. (2005). According to Cole, Bellizzi, Flegal, and Dietz (2000), all of them could be categorized as severely obese (mean ABMI 1 = 163.86, SD=14.97; 7 boys; age M=12.79, SD=2.68; range 9–18 yo). 2.2. Treatment program The treatment consisted of a maximum twelve-month multi-component inpatient program. The duration of the treatment depended on the individual therapy goal of each participant. Every week and half of the school holidays, the youngsters returned home. The program focused on attaining a healthy lifestyle by increasing physical activity and offering a healthy diet within a cognitive behavioural framework. For an extensive description of the program, we refer to Braet et al. (2003). In short, concerning physical activity, all children received an individual physical training program for 4 h a week, including swimming, biking and fitness. Before and after school they were stimulated to participate for at least 2 h a day in active games and lifestyle activities. During the weekends and the holidays they spent at home, they noted how much they were physical active, using a diary. Provided that a stringent calorie restriction is not recommended for youngsters that are still growing, the diet contained between 1500 and 1800 kcal/day. More specifically, it consisted of three meals and three snacks per day. The consumption of soft drinks, sweets and high-calorie food was strictly regulated, but not completely banned. Further, the psychological counselling consisted of a twelve-week cognitive behavioural treatment program in small groups, followed by weekly individual problem-solving-based booster sessions. In order to change their lifestyle, the youngsters were taught self-modulating skills, such as self-regulation (e.g., self-observation and self-instruction), self-evaluation, and self-reward. Finally, the program also involved the parents. Theywereprovided information in how the lifestyle of their child could change within the family. 2.3. Materials 2.3.1. Extrinsic Affective Simon Task Participants conducted two EASTs: One task was related to physical activity, and one related to food. An EAST assessing attitudes consists of attribute stimuli (words carrying a clear valence) and target stimuli (stimuli of which the attitudes are assessed). Individually selected attractive food and physical activity words were used for the attribute stimuli. In the physical activity EAST, targets were nine pre-selected words related to physical activity, divided into three categories: sedentary activities (e.g., watching television), moderate intense activities (e.g., swimming) and high intense activities (e.g., exercising). In the food EAST, targets were pre-selected words related to food, divided into two categories: unhealthy food (e.g., French fries) and healthy food (e.g., apple). All target stimuli words are presented in the Appendix. For a more extended description of the EASTs, we refer to Craeynest et al. (2005). 2.3.2. Self-reports Participants had to rate the valence of the food and physical activity target stimuli words of the EASTs on a 7-point rating scale, ranging from ‘dislike’ (−3) to ‘like’ (+3). 2.4. Procedure M. Craeynest et al. / Eating Behaviors 9 (2008) 41–51 This study was approved by the Ethical committee of Ghent University. To investigate their change over the treatment period, participants were tested three times: at baseline (during the first three weeks of the treatment; T1), 1 The Body Mass Index (BMI; weight/height 2 ; kg/m 2 ) is accepted as a reliable and valid index of relative adiposity. However, as mean normal values of BMI vary substantially with age and values for individuals of different ages are difficult to compare, an adjusted BMI (ABMI) was used. ABMI was calculated using the formula (actual BMI/ideal BMI [50th percentile for same sex and age])×100 (Valverde, Patin, Oliveira, Lopez, & Vitolo, 1998). The 50th percentiles were derived from Flemish growth reference charts. An ABMI of 100% is considered ideal. 43
Page 1: Abstract The role of implicit attit
Page 5 and 6: Table 1 Mean and standardized (SD)
Page 7 and 8: Table 3 Regression analyses predict
Page 9 and 10: 3.5.2. Implicit attitudes towards f
Page 11: Target stimuli physical activity: S

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