A new study published in Food Quality and Safety on May 20, 2026, reveals that hunger amplifies the appeal of sweet tastes regardless of whether they contain calories, and that habitual consumers of non-nutritive sweeteners (NNS) exhibit heightened activity in a brain region linked to self-control when tasting sweet solutions. The findings, from researchers at Jiangnan University in China and the University of Oxford in the United Kingdom, challenge assumptions about how metabolic state and long-term sweetener use shape taste preferences.
Excessive sugar intake is a major driver of obesity, type 2 diabetes, and cardiovascular disease, prompting widespread use of non-nutritive sweeteners as low-calorie alternatives. However, concerns have grown that chronic NNS consumption might decouple sweet taste from metabolic energy signaling, potentially reshaping taste preferences and reward pathways. Long-term trials have produced conflicting results, with some studies showing shifts in sweet preference and others finding no change. This study directly compared habitual sugar consumers and habitual NNS 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 participants said they liked and how their brains and bodies responded. Participants consistently rated all sweet solutions as more enjoyable when hungry, regardless of whether those solutions contained sugar or only NNS. 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).
“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.” The results indicate that the craving for energy made sweetness itself more appealing, not the calories behind it.
More strikingly, habitual NNS consumers showed a distinct neural signature. While their self-reported liking and emotional responses did not differ from sugar consumers, fNIRS 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. “It is as if their brains are working a little harder to keep their sweet intake in check,” the authors noted. “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.”
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. Nonetheless, the results offer practical guidance for public health and the food industry. Because hunger enhances the appeal of any sweet taste, replacing sugar with NNS in snacks consumed between meals might still satisfy cravings without adding calories. The heightened brain activity in habitual NNS 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. The research was supported by the National Key Research and Development Program of China (Grant No. 2025YFF1107600) and the Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, China. The full study is available at https://doi.org/10.1093/fqsafe/fyag046.
