Food and emotions: Assessing the effects of food behaviors and prior associations on the emotional response to food consumption

Because of the impact diet and food choice have on health, and the role that emotion may play in food choice, a growing research interest in the links between food and emotion has emerged. The research presented in this thesis attempted to further the understanding of the relationships between food and emotion, focusing particularly on the effects of certain food behaviors on mood, and the formation of emotional associations with food. The objective of Part 1 was to determine whether having a choice of meal components (vs. no choice) and/or preparing a meal (vs. someone else preparing) influenced the stress-relieving and mood-boosting effects of food and eating. One hundred eighteen participants completed a laboratory stress task in which they were asked to deliver an impromptu speech and to do complex mental arithmetic. Following the stress task, participants consumed a pasta meal. Participants either chose the components of their pasta meal or not (experimenter chose the components for them), and either prepared it themselves or not (experimenter prepared it for them). Stress (salivary cortisol, heart rate, and blood pressure) and mood (adapted Profile of Mood States) were measured several times throughout the experiment. Not choosing the meal components resulted in greater reductions in anxiety and anger than choosing. Systolic blood pressure was reduced more in the no choice than in the choice condition after the meal. Preparing versus not preparing had little effect on stress and mood measures. Given that people generally have emotional responses to food and eating experiences, the second part of this thesis explored why and how those emotional associations are formed. The main objective of Part 2 was to attempt to induce positive emotional associations with novel foods in the laboratory by conditioning the foods with emotionally positive film clips. The effect of calorie content of foods on formation of emotional associations was also examined, as was the relationship between liking ratings of the novel foods and emotional associations. One hundred participants completed a conditioning procedure in which they ate novel foods (High-Calorie foods or Low-Calorie foods) while viewing film clips (Positive film clips or Neutral film clips) for four consecutive days. Prior to conditioning, they made baseline ratings of explicit (Positive and Negative Affect Schedule) and implicit (Implicit Positive and Negative Affect Test) emotional associations and liking (9-point hedonic scale). On the day after the last conditioning session, and also one week later, participants rated explicit and implicit emotional associations and liking again. Positive emotional associations were not successfully induced with novel foods. No differences in emotional associations between high-calorie and low-calorie foods were observed. A major limitation was that the film clips did not reliably increase participants' positive mood, which may have contributed to the failure of our conditioning procedure. Liking ratings of the novel foods increased throughout the duration of the study, and were positively associated with positive emotional associations. The research presented in this thesis demonstrates the complexity of the relationships between food and emotions, and sheds light on the many methodological issues to consider when studying these relationships.