This study examined the effects of a novel treatment package consisting of Acceptance and Commitment Therapy (ACT)-based activities with and without contingent rewards on children's consumption of low-preferred healthy foods. Participants were 6, 3-5-year-old children who attended a local day care center. The effects of the two treatment packages on children's tasting, approach, and amount of food consumed were assessed using a multiple baseline design across food categories. During the ACT-based mindfulness condition, the experimenter led a set of four ACT activities prior to the presentation of food. This condition produced a mean increase in foods tasted of 7.4% for fruits but 0% for vegetables, and mean increases in the approach of 18.6% for fruits and 8.7% for vegetables. A second condition consisting of the same ACT activities plus rewards delivered contingent upon tasting the foods produced mean increases in foods tasted of 69.2% for vegetables, 25.3% fruits, and 43.2% for beans, and increases for foods approached of 54.7% for vegetables, 16.2% for fruits, and 44.6% for beans. Both intervention conditions resulted in low mean amounts of food consumed with 0% of vegetables and 17.4% of fruits consumed during the ACT condition, and 1.6%, 6.7%, and 2.6% consumed during the ACT plus rewards condition for vegetables, fruits, and beans respectively. Implications of the results are discussed in terms of their relevance to past and future research.

A prospective, longitudinal and observational study, using a non-clinical population of mother-child dyads was conducted to evaluate the contribution of family-environmental factors in predicting child food avoidance and feeding problems across early childhood. The contribution of maternal feeding practices, mealtime structure and interactional behaviour during mealtimes, were explored in predicting child food avoidance between 2 and 5 years, whilst also evaluating the role of maternal psychopathology and child temperament. This thesis also assessed the validity of maternal reports of child eating behaviour and feeding practices by obtaining independent observations of these constructs, and explored the longitudinal stability and continuity of both independent observations and maternal reports of child eating behaviour and maternal feeding practices. Concurrently and prospectively, observations of mothers eating with their child, displaying high sensitivity, low control, and more positive emotion and verbalisation during mealtimes predicted less avoidant child eating behaviour. Reports of mothers providing a healthy food-related home environment, encouraging balanced food intake, and involving their child in food planning, in addition to a less emotional child temperament, were also significant longitudinal predictors of less avoidant child eating behaviour. Maternal descriptions of their child s eating behaviour were validated by independent observations; however maternal descriptions of their own feeding practices were not. Child eating behaviour and maternal feeding practices were predominantly stable and continuous across early childhood, with the exception of child difficulty to feed and maternal pressure to eat which decreased between the ages of 3 and 4. This thesis demonstrates many interesting and novel findings but primarily through the utilisation of observational and longitudinal data it demonstrates the important causal contribution of family-environmental factors in the development of food avoidant eating behaviours during early childhood.

Objective: Although patients with avoidant/restrictive food intake disorder (ARFID) often consult general pediatric services initially, existing literature mostly concentrated on ntensive eating disorder treatment settings. This cross-sectional study sought to describe symptoms of ARFID and their associations with eating disorder psychopathology, quality of life, anthropometry, and physical comorbidities in a general pediatric sample. Methods: In N = 111 patients (8-18 years) seeking treatment for physical diseases, prevalence of ARFID-related restrictive eating behaviors was estimated by self-report and compared to population-based data (N = 799). Using self-report and medical record data, further ARFID diagnostic criteria were evaluated. Patients with versus without symptoms of ARFID based on self-report and medical records were compared in diverse clinical variables. Results: The prevalence of self-reported symptoms of ARFID was not higher in the inpatient than population-based sample. Only picky eating and shape concern were more common in the inpatient than population-based sample. Although 69% of the inpatient sample reported any restrictive eating behaviors, only 7.2% of patients showed symptoms of ARFID based on medical records in addition to self-report, particularly those with underweight, without significant effects for age, sex, and medical diagnoses. Discussion: The study revealed the importance of considering ARFID within the treatment of children and adolescents with physical diseases, especially for those with underweight. Further research is needed to replicate the findings with interview-based measures and to investigate the direction of effects in ARFID and its physical correlates.

Although restrictive eating behaviors are very common during early childhood, their precise nature and clinical correlates remain unclear. Especially, there is little evidence on restrictive eating behaviors in older children and their associations with children's shape concern. The present population-based study sought to delineate subgroups of restrictive eating patterns in N = 799 7-14 year old children. Using Latent Class Analysis, children were classified based on six restrictive eating behaviors (for example, picky eating, food neophobia, and eating-related anxiety) and shape concern, separately in three age groups. For cluster validation, sociodemographic and objective anthropometric data, parental feeding practices, and general and eating disorder psychopathology were used. The results showed a 3-cluster solution across all age groups: an asymptomatic class (Cluster 1), a class with restrictive eating behaviors without shape concern (Cluster 2), and a class showing restrictive eating behaviors with prominent shape concern (Cluster 3). The clusters differed in all variables used for validation. Particularly, the proportion of children with symptoms of avoidant/restrictive food intake disorder was greater in Cluster 2 than Clusters 1 and 3. The study underlined the importance of considering shape concern to distinguish between different phenotypes of children's restrictive eating patterns. Longitudinal data are needed to evaluate the clusters' predictive effects on children's growth and development of clinical eating disorders.

Objective: This study sought to determine the factor structure of the newly developed self-report screening questionnaire Eating Disturbances in Youth-Questionnaire (EDY-Q) as well as to report the distribution of variants of early-onset restrictive eating disturbances characteristic of avoidant/restrictive food intake disorder (ARFID) in a middle childhood population sample. Method: Using the EDY-Q, a total of 1444 children aged 8-13 years were screened in elementary schools in Switzerland via self-report. The factor analysis of the 12 items covering ARFID related symptoms was performed using a principal component analysis (PCA). Results: The PCA showed a four factor solution, with clear allocation to the scales covering three variants of early-onset restrictive eating disturbances and weight problems. Inadequate overall food intake was reported by 19.3% of the children, a limited accepted amount of food by 26.1%, and food avoidance based on a specific underlying fear by 5.0%. Discussion: The postulated factor structure of the EDY-Q was confirmed, further supporting the existence of distinct variants of early-onset restrictive eating disturbances. Avoidant/restrictive eating behavior seems to be a common experience in middle childhood, but results have to be confirmed using validated interviews.

Objective: This study sought to determine the factor structure of the newly developed self-report screening questionnaire Eating Disturbances in Youth-Questionnaire (EDY-Q) as well as to report the distribution of variants of early-onset restrictive eating disturbances characteristic of avoidant/restrictive food intake disorder (ARFID) in a middle childhood population sample. Method: Using the EDY-Q, a total of 1444 children aged 8-13 years were screened in elementary schools in Switzerland via self-report. The factor analysis of the 12 items covering ARFID related symptoms was performed using a principal component analysis (PCA). Results: The PCA showed a four factor solution, with clear allocation to the scales covering three variants of early-onset restrictive eating disturbances and weight problems. Inadequate overall food intake was reported by 19.3% of the children, a limited accepted amount of food by 26.1%, and food avoidance based on a specific underlying fear by 5.0%. Discussion: The postulated factor structure of the EDY-Q was confirmed, further supporting the existence of distinct variants of early-onset restrictive eating disturbances. Avoidant/restrictive eating behavior seems to be a common experience in middle childhood, but results have to be confirmed using validated interviews.