Beliefs about dietary fat and sugar and their association with self-reported dietary adjustments leading up to cognitively demanding situations : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Psychology at Massey University, Albany, New Zealand

Abstract

Diet has for a long time been known to play a crucial role in human health and well-being. While fat and sugar are both essential to healthy brain function, long-term overconsumption– particularly of refined sugars, saturated fats, and trans fats–has been linked to negative effects on cognition and mood. Attitudes and beliefs significantly influence health-related behaviours, including dietary choices, emphasizing the importance of understanding public perceptions to promote healthier eating habits. While the effects of dietary fat and sugar on health have been extensively studied, little is known about how the public perceives their impact on mood and cognition. Given the prevalence of negative attitudes and narratives surrounding fat and sugar, it is possible that people also hold negative beliefs about their effect on mood and cognition. The present study surveyed 205 participants on their beliefs regarding fat and sugar’s impact on cognitive performance and mood across several domains using agree/disagree scales. Participants also reported how they would modify their diet leading up to hypothetical cognitively demanding scenarios, such as university exams or job interviews. The results of this study provide some evidence of a popular belief that fat and sugar negatively affect both mood and cognition. Additionally, reported changes in dietary consumption were found to be associated with beliefs about mood but not cognition. Possible explanations for these findings are discussed in relation to the health belief model, alongside study limitations and directions for future research.