Understanding and Changing Eating Behavior : In-the-Moment Assessments Provide New Perspectives for Health Promotion

The rising prevalence of non-communicable diseases challenges health psychology research to find effective intervention strategies to change people´s health behaviors. It is particularly important to change eating behavior since this constitutes one of the most important preventive health behaviors. To facilitate eating behavior changes, new technologies such as smartphone applications (apps) are booming and are increasingly being considered in intervention development. App-based mobile interventions not only include a wide range of technical options along with the capability to reach a broad spectrum of the population, but also the possibility to intervene in real-life and real-time.In order to use these advantages and open up new perspectives for changing eating behavior, the present dissertation aims to determine and quantify the potential of app-based mobile interventions for changing eating behavior by synthesizing the existing evidence. Moreover, deriving conclusions for future intervention development first requires a comprehensive understanding of eating behavior and its underlying psychological determinants as a necessary initial step towards changing it. For this purpose, the core determinants of daily eating behavior, including in-the-moment eating motives and eating happiness, are examined using an Ecological Momentary Assessment approach.The first step of the present dissertation is to detemine the potential of app-based mobile interventions as an effective strategy for achieving changes in eating behavior in a large spectrum of the population. For this purpose, a systematic review and meta-analysis is conducted, including 41 studies and comprising 6,348 participants and 373 investigated outcomes. This shows that app-based mobile interventions are effective in changing eating behavior, including positive effects on fruit and vegetable intake. Moreover, positive changes in nutrition-related health outcomes such as obesity indices and clinical parameters are observed, showing small-to-moderate effect sizes. Overall, the present evidence confirm the high potential of app-based mobile interventions for health promotion, and can support both research and practice in further exploiting their full potential.In a second and third step, the core psychological determinants of daily eating behavior are investigated by analyzing in-the-moment eating motives and eating happiness experienced in-the-moment to achieve a comprehensive understanding of the targeted behavior. In both studies, a smartphone-based Ecological Momentary Assessment is conducted over the course of a week to assess eating behavior, along with eating motives and eating happiness. Moreover, in addition to this real-life and real-time assessment approach, the present dissertation aims to point out new paths for data analysis, and a new visualization approach is introduced to handle the resulting high-dimensional data and allow an analysis at the between- and within-person levels. By combining the ecological valid assessment method with this comprehensive data analysis, the present dissertation gains considerable insight into the psychological determinants of daily eating behavior.The investigation of eating motives as core motivators for daily food choices reveals differences between why people think they eat (dispositional assessment) and why they actually eat in the moment of consumption (in-the-moment assessment). In particular, visual appeal, liking, and pleasure show a high impact on in-the-moment eating behavior and can therefore contribute to the development of future app-based mobile interventions. Moreover, a more sophisticated analysis on the person and motive levels indicates considerably inter- and intra-individual differences, highlighting the importance of tailoring interventions not only to the individual but also to the situation.Further, the investigation of eating happiness experienced in-the-moment as one important determinant of daily food choices indicates promising results for health promotion. Comparing eating happiness among different food categories reveals that healthy food choices such as fruits and vegetables evoke at least comparable to or even higher eating happiness than unhealthy food choices. Out of 14 different food categories, vegetable consumption contributes the largest proportion of total eating happiness, which indicates a ‘happy = healthy’ association. On the basis of these findings, it can be concluded that healthy food choices seem to also be happy food choices, and that the consumption of fruits and vegetables has both immediate and long-term beneficial psychological effects.Bringing the present findings together, could pave the way towards a new approach in health promotion. By using in-the-moment interventions, eating happiness could be promoted as an important motivator that both drives human food choices and acts as an important cue for healthy eating. This might constitute an innovative intervention strategy that not only triggers healthy but also happy eating behaviors and enables the focus to be shifted towards a more positive and wellbeing-centered perspective on eating behavior.publishe