Hunger can make sweet foods harder to ignore. A new exploratory study suggests that may have less to do with calories than with sweetness itself.
The study, published in Food Quality and Safety, compared habitual sugar consumers and habitual non-nutritive sweetener consumers as they tasted sweetness-matched solutions while hungry and after eating. Researchers found that participants rated sweet solutions as more enjoyable when hungry, whether the sweetness came from sugar or a non-nutritive sweetener. The study does not show that sugar substitutes are good or bad for weight, cravings or metabolic health. It also does not prove that non-nutritive sweeteners improve self-control.
The findings add a small but interesting piece to a larger question: How do hunger, habit and sweet taste shape what people want to eat?
Researchers from Jiangnan University in China and the University of Oxford studied responses to sweet solutions using several measures, including self-reported liking, emotional assessments, electrocardiogram readings and functional near-infrared spectroscopy, a brain-imaging method that can measure changes in blood oxygenation.
Participants consistently rated sweet solutions as more enjoyable when they were hungry. That pattern held whether the solutions contained sugar or non-nutritive sweeteners. In other words, hunger appeared to increase the appeal of sweet taste itself, not only sweetness paired with calories.
The researchers also saw signs of physiological arousal when participants tasted sweet solutions while hungry, including increased heart rate. That does not mean sweetness caused stress or danger. It suggests the body may become more responsive to sweet taste when energy needs feel more immediate.
“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 study also found a difference between habitual sugar consumers and habitual non-nutritive sweetener consumers. People who regularly consumed non-nutritive sweeteners showed stronger activity in the left dorsolateral prefrontal cortex, a brain region involved in cognitive control and self-regulation, while tasting sweet solutions.
That finding is intriguing, but it should be interpreted carefully. Stronger activity in a self-control-related brain region does not prove that sweeteners train the brain, reduce cravings or help people make healthier food choices. It may reflect attention, learned restraint or another form of mental processing around sweet taste.
The authors described the pattern as a possible sign that habitual non-nutritive sweetener users were working harder to regulate their response to sweetness.
“It is as if their brains are working a little harder to keep their sweet intake in check,” the authors said. “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 has several limits. It was exploratory, meaning it was designed to look for patterns rather than deliver a final answer. It measured immediate responses to sweet solutions, not what people ate later in real life. The emotional assessment portion also involved a relatively small sample of 15 participants per group, so those findings should be treated as early evidence.
That caution matters because sugar substitutes are often discussed in extremes. Some people see them as an easy way to reduce added sugar. Others worry they may keep people attached to highly sweet tastes. This study does not settle that debate.
What it does suggest is simpler and more relatable: Hunger may make sweetness more appealing in the moment, whether it comes from sugar or a non-nutritive sweetener. For people trying to understand cravings, that may be useful context. The pull toward something sweet may not always be about needing sugar specifically. Sometimes, the hungry brain may simply find sweetness more rewarding.
The study was funded by the National Key Research and Development Program of China and the Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, China.