An exploratory study of sweetness preference for habitual sugar and non-nutritive sweetener consumers revealed by explicit and implicit measures

Abstract This study investigated whether hunger and satiety modulate hedonic, affective, autonomic, and prefrontal hemodynamic responses to sweetness-matched solutions in habitual consumers of sugar and non-nutritive sweeteners. Three iso-sweet stimuli (full-sucrose, half-sucrose, and zero-sucrose) were validated against a 6% sucrose reference using time-intensity and triangle tests. During hunger and satiety states, 15 participants per group evaluated the solutions using explicit measures (hedonic scales, Self-Assessment Manikins, and EsSense profile in check-all-that-apply format), while implicit physiological responses were recorded via electrocardiogram and functional near-infrared spectroscopy. Hunger increased liking for sweet solutions in both groups without selectively favoring caloric sugar over non-caloric sweetness. It also slightly enhanced emotional arousal and valence, shifting emotional profiles from “mild/bored” toward “joyful/interested/satisfied”. This shift was accompanied by significantly shorter R-R intervals and higher heart rate without significant increases in high-frequency power or root mean square of successive differences, indicating greater physiological arousal under hunger. Additionally, habitual non-nutritive sweetener consumption did not alter self-reported liking, affective responses, or electrocardiogram-derived autonomic indices under blind tasting. However, non-sugar group participants showed significantly higher oxygenated hemoglobin responses in the left dorsolateral prefrontal cortex, suggesting enhanced control-related prefrontal processing during sweet-taste evaluation. These findings suggested that sweetness itself, rather than caloric content, drives hunger-related increases in immediate liking and physiological arousal. They also raised the possibility of sensory substitutability of non-nutritive sweeteners for fulfilling hedonic rather than metabolic needs.