Master of Science / Department of Human Nutrition / Tandalayo Kidd / Weiqun Wang / The number of overweight and obese college students in the United States has remained high, which could be related to the comfort food and beverages consumed. Sugar-sweetened beverages and fried potatoes are beverages and comfort food commonly consumed by college students. Furthermore, people’s behavior is affected by their perceptions and goals. Thus, this study aimed to assess the correlations between the perception, goal of body weight, and sugar-sweetened beverages and fried potatoes consumption behaviours of college students. A cross-sectional survey of 371 college students was conducted via a self-reporting questionnaire that included information related to sugar-sweetened beverages and fried potato consumption behavior in the past month. The involved students also described their body weight perception and future goal. Spearman correlation and Chi-square analyses were performed to examine the associations. There were significant associations (p<0.0001) between perception of body weight and goal of body weight, regular soda consumption and other sweetened beverage consumption, regular soda consumption and fried potato consumption, and other sweetened beverage consumption and fried potatoes consumption. In addition, there were significant correlations between goals of body weight and other sweetened beverage consumption (p=0.0370). These findings confirmed that perception of body weight was associated with goal of body weight and provided a significant importance for educational intervention to students on improving awareness of healthy body weight and eating.

Många drabbas av social ångest. Vikt och kroppsuppfattning relaterar till social ångest men sambandet behöver tydliggöras. Syftet med studien var att se hur mycket av variationen i social ångest över tid som kan förklaras av vikt-, och kroppsrelaterade mått, samt undersöka könsskillnader. Studien var longitudinell och baserades på en enkätundersökning vid två insamlingstillfällen med ett års mellanrum (N=361). Resultatet visade att upplevd övervikt, felaktigt upplevd övervikt, kön och kroppsnöjdhet tillsammans förklarade 7 % av variationen i social ångest över tid. Tjejer som var missnöjda med sina kroppar löpte ökad risk att rapportera högre grad av social ångest vid tidpunkt 2. Slutsatsen är att tjejer och killar har olika relation till sina kroppar vilket bör beaktas vid behandling och prevention. / Many people suffer from social anxiety. There is a relationship between weight and body perception connected to social anxiety but the link needs to be sorted out. The aim with our study was to clarify to what extent social anxiety is due to weight and body related concerns and to examine gender differences. The study was longitudinal and based on a survey performed at two occasions with one year interval (N=361). The result showed that perceived overweight, incorrectly perceived overweight, gender and body satisfaction predicts 7 % of the variety in social anxiety one year ahead. Girls who were dissatisfied with their bodies ran an increased risk reporting a higher level of social anxiety at the second occasion. Conclusively, as girls' and boys' relationships with their bodies differ, this findings should be considered in treatments and preventive programs.

Cette thèse a pour objectif l’examen des conséquences de la stigmatisation du surpoids chez les jeunes femmes qui se perçoivent en surpoids (que cette perception soit justifiée ou non) via le phénomène de menace du stéréotype (Steele & Aronson, 1995). Nous proposons que des contextes menaçants, en lien avec les stéréotypes négatifs qui portent sur les comportements alimentaires des personnes en surpoids, peuvent biaiser l’estimation que ces femmes font des aliments et augmenter leur consommation d’aliments réconfortants. Les études expérimentales de ce travail doctoral confirment ces hypothèses : leurs résultats indiquent que plus les femmes pensent avoir un excès de poids, (i) moins elles réussissent à estimer la teneur calorique des aliments et à sélectionner les plats en fonction de leurs valeurs nutritionnelles, et (ii) plus elles consomment d’aliments gras et sucrés. Nous investiguons également le rôle médiateur des émotions (et notamment celui de l’anxiété) ainsi que sur celui de la réduction des ressources disponibles en mémoire de travail dans ces effets. Si nos études ne permettent pas d’affirmer l’implication de mécanismes émotionnels, une de nos études met en cause la diminution des ressources en mémoire de travail.Bien que d’autres études ont déjà fait état des conséquences de la menace du stéréotype lié au surpoids chez les personnes objectivement en surpoids (e.g., Brochu & Dovidio, 2014), les études de cette thèse sont les premières à mettre en évidence les conséquences de ce phénomène chez les femmes qui se perçoivent en surpoids, et à confirmer qu’il est nécessaire de prendre en compte cette variable dans l’étude des conséquences de la stigmatisation du surpoids. / This thesis aims to examine the consequences the stigma of overweight among young women who perceive themselves as overweight (whether this perception is justified or not), via the phenomenon of stereotype threat (Steele & Aronson, 1995). We propose that threatening contexts (in which negative stereotypes are about the eating behaviours of overweight people are activated), can (i) bias overweight self-perceived women's nutritional values assessment, and thus lead them to select dishes that are not adapted to their needs, and (ii) increase their consumption of comfort food. The experimental studies of this doctoral work tend to confirm these hypotheses: their results indicate that the more young women think they are overweight, (i) the less successful they are at estimating the calorie content of foods and selecting dishes on the basis of their nutritional values, (ii) the more they consume fatty and sugary foods. We also investigate the roles of emotions (especially anxiety) and working memory resources in these effects. Although our studies do not allow us to assert the involvement of emotional mechanisms, one of our studies underlines the role of a decrease in working memory resources. While other studies have already reported the deleterious consequences of overweight stereotype threat in objectively overweight individuals (e.g., Brochu & Dovidio, 2014), ours are the first to report on the consequences of this phenomenon in overweight self-perceived women, and confirm that weight perception must be taken into account in studies on the negative health consequences associated with weight stigma.

This study explored the perception of weight in virtual reality using the combination of limiting the velocity with which an object can be lifted and control/display ratio modification and what affordances and challenges the combination might bring. Both interaction methods have thus far been explored independently, but not together. A virtual reality environment was designed that allowed each interaction method to be tested independently and together. A between-subjects user study was conducted where participants did multiple weight discrimination tasks along with a task involving absolute weight estimation. Results indicated that the combination of the two interaction methods increased the accuracy of weight discrimination considerably while not allowing for absolute weight estimation. It also increased the likelihood of noticing the interaction method with some participants that tested only one interaction method struggling to distinguish between the weights. Future work is required to reduce the frustrations that dropping objects due to the velocity limit caused among participants. / Denna studie undersökte uppfattningen om vikt i virtuell verklighet genom att kombinera begränsning av lyftförmågan hos ett objekt med ä ndring av kontroll-/visningsförhållande och vilka möjligheter och utmaningar denna kombination kan medföra. Båda interaktionsmetoderna har hittills undersökts separat, men inte tillsammans. En virtuell verklighetsmiljö utformades som möjliggjorde testning av varje interaktionsmetod separat och tillsammans. En användarstudie med mellangruppsdesign genomfördes där deltagarna utförde flera uppgifter för viktdiskriminering samt en uppgift för att uppskatta absolut vikt. Resultaten indikerade att kombinationen av de två interaktionsmetoderna avsevärt ökade noggrannheten för viktdiskriminering samtidigt som den inte tillät uppskattning av absolut vikt. Det ökade också sannolikheten för att märka interaktionsmetoden hos vissa deltagare, där de som endast testade en interaktionsmetod hade svårt att skilja mellan vikterna. Framtida arbete krävs för att minska frustrationen då ett objekt tappas på grund av hastighetsbegränsningen vilket orsakades bland deltagarna.