Hunger Boosts Sweet Appeal; Zero-Calorie Sweeteners May Alter Brain Control

A groundbreaking study published in Food Quality and Safety reveals that hunger amplifies the appeal of sweetness itself, regardless of caloric content. Researchers from Jiangnan University and the University of Oxford found that hungry participants rated sweet solutions as more enjoyable whether they contained sugar or non-nutritive sweeteners (NNS). This was accompanied by physiological signs of arousal, such as increased heart rate. The study, led by scientists in China and the UK, used subjective ratings, emotional assessments, electrocardiogram (ECG), and functional near-infrared spectroscopy (fNIRS) to dissociate perceived liking from neural responses.

The research compared habitual sugar consumers with habitual NNS consumers under hungry and satiated conditions. While both groups reported similar liking and emotional responses, NNS consumers showed significantly stronger oxygenated hemoglobin responses in the left dorsolateral prefrontal cortex (DLPFC), a brain region linked to self-control and dietary regulation. This neural activity suggests that long-term NNS use may strengthen cognitive control during sweet taste processing, potentially helping individuals manage hedonic urges. The findings challenge the assumption that zero-calorie sweeteners are neutral, indicating they may reshape brain function over time.

The study's implications for public health and the food industry are significant. Since hunger enhances the appeal of any sweet taste, replacing sugar with NNS in between-meal snacks could satisfy cravings without adding calories. However, the heightened brain activity in NNS users raises questions about whether these sweeteners reinforce cognitive control or merely reflect an ongoing struggle with temptation. The authors caution that the emotion analysis involved a small sample, but the core message is clear: sweetness itself, not just its energy, drives hunger-related eating behavior. Reformulating products to be less sweet overall may be a more effective long-term strategy than simply swapping sugar for alternatives.