Understanding sweet liking and disliking: re-evaluating sweet taste as a driver of overconsumption

Given the role of taste hedonics in directing ingestive behaviour, the abundance of highly palatable foods that characterises the modern food environment may contribute to the high prevalence of unhealthy eating habits and obesity globally. Sweetness has long been considered to elicit strong liking and, therefore, to drive overconsumption, possibly leading to weight gain. Despite these claims, Chapter 2 identified over 70 research papers reporting large variations in hedonic response to sweetness. Using sucrose solutions and hierarchical cluster analysis, Chapter 3 confirmed this variation, demonstrating three distinct sweet-liking patterns: a rise in liking with increasing sucrose concentration (sweet liker phenotype, SL), an inverted-U response pattern, and a decline in liking as concentration increased (sweet disliker phenotype, SD). Chapter 2 also identified inconsistencies, methodological weaknesses or limitations in adoption for large-scale studies in the previous methods used to quantify different sweet-liking patterns. To facilitate future research, Chapter 3established rapid and reliable swee-liking phenotype classification criteria. Chapter 4 confirmed the robustness of these criteria in a cross-country sample, and also explored the effect of phenotype on selected anthropometric, dietary, and behavioural characteristics: SLs had either lower fat mass or greater fat free mass than SDs and behavioural characteristics analogous to those of high interoceptive performers. A possible interaction between the obesogenic environment and most phenotype-specific effects was also suggested. In Chapter 5, SLs were found to perform better than SDs in objective cross-modal interoception tasks and to be more mindful and intuitive eaters. Chapter 6 tested the effect on affective responses to different tastants of an 8-day exposure to a diet high in simple sugars versus a control group. Contrary to liking for sucrose solutions, findings indicated a phenotype by condition interaction for hedonic responses to highly palatable foods and drinks with SDs experiencing the largest effect (increase)