Excessive sugar intake is a major driver of obesity, type 2 diabetes, and cardiovascular disease. In response, non-nutritive sweeteners have become widely used as low-calorie alternatives. However, concerns have grown that chronic non-nutritive sweetener consumption might decouple sweet taste from metabolic energy signaling, potentially reshaping taste preferences and reward pathways in unexpected ways. Long-term trials have so far produced conflicting results, with some studies showing shifts in sweet preference and others finding no change. Based on these challenges, a deeper investigation into how metabolic state and habitual non-nutritive sweetener use jointly influence sweet preference is urgently needed.
Researchers from Jiangnan University in China and the University of Oxford in the United Kingdom published (DOI: 10.1093/fqsafe/fyag046) their findings in the journal Food Quality and Safety on May 20, 2026. The study directly compared habitual sugar consumers and habitual non-nutritive sweetener consumers, measuring their responses to sweetness-matched solutions under both hungry and satiated conditions. Using a combination of subjective ratings, emotional assessments, electrocardiogram (ECG), and functional near-infrared spectroscopy (fNIRS), the team uncovered a dissociation between what people say they like and how their brains and bodies respond.
Participants consistently rated all sweet solutions as more enjoyable when hungry, regardless of whether those solutions contained sugar or only non-nutritive sweeteners. This hunger-driven boost in liking was accompanied by clear physiological signs of sympathetic nervous system arousal, including significantly shortened R-R intervals (RR-I) and increased heart rate (HR). Contrary to the team's initial hypothesis, hunger did not selectively favor caloric sugar over non-caloric sweetness. In other words, the craving for energy made sweetness itself more appealing, not the calories behind it.
More strikingly, habitual non-nutritive sweetener consumers showed a distinct neural signature. While their self-reported liking and emotional responses did not differ from sugar consumers, functional near-infrared spectroscopy revealed significantly stronger oxygenated hemoglobin (O₂Hb) responses in their left dorsolateral prefrontal cortex (DLPFC) — a key region for cognitive control, dietary self-regulation, and resisting temptation. This neural difference emerged even though all samples were tasted blindly and matched perfectly for sweetness intensity, ruling out simple perceptual explanations. Notably, the study's CATA（check-all-that-apply）emotion analysis involved a relatively small sample of 15 participants per group, so those findings should be interpreted with caution.
The findings suggest that long-term use of non-nutritive sweeteners may be associated with enhanced prefrontal surveillance during sweet taste processing, potentially reflecting a learned cognitive strategy to manage the hedonic appeal of sweet foods.
“Hunger seems to turn up the volume on sweetness itself, making it more appealing whether it comes with calories or not,” the authors said. “That was a surprise — we expected hungry people to reach specifically for sugar. But we also saw that habitual non-nutritive sweetener users showed a stronger brain response in a region linked to self-control. It is as if their brains are working a little harder to keep their sweet intake in check. This doesn’t prove that zero-calorie sweeteners are good or bad, but it does suggest they are not simply neutral — they may change how our brains handle sweet tastes over time.”
These findings offer practical guidance for public health and the food industry. Because hunger enhances the appeal of any sweet taste, replacing sugar with non-nutritive sweeteners in snacks consumed between meals might still satisfy cravings without adding calories. The heightened brain activity in habitual non-nutritive sweetener users raises the possibility that these sweeteners could help reinforce cognitive control over food choices, though this remains to be tested. For now, the study suggests that sweetness itself — not just its energy content — powerfully drives hunger-related eating behavior. Reformulating products to be less sweet overall, while ensuring they are still pleasurable, may be a more effective long-term strategy than simply swapping sugar for zero-calorie alternatives.
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References
DOI
10.1093/fqsafe/fyag046
Original Source URL
https://doi.org/10.1093/fqsafe/fyag046
Funding information
National Key Research and Development Program of China (Grant No. 2025YFF1107600); Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, China
About Food Quality and Safety
Food Quality and Safety is an open access, international, peer-reviewed journal providing a platform to highlight emerging and innovative science and technology in the agro-food field, publishing up-to-date research in the areas of food quality, food safety, food nutrition and human health. It is covered by SCI-E and the 2025 Impact Factor (IF)=4.9, 5-yr IF=4.9