What if how much you enjoy a drink depends less on what’s in it and more on what you think is in it?
A new peer-reviewed study published in JNeurosci suggests that expectations about whether a beverage contains sugar or artificial sweetener can significantly influence how pleasant it tastes and how the brain responds to it.
Researchers from Radboud University, the University of Oxford and the University of Cambridge recruited 99 healthy adults with similar reported liking for sugar and artificial sweeteners. Participants tasted beverages that contained either sugar or an artificial sweetener. In some cases, they were told the correct ingredient. In other cases, researchers deliberately misled them.
The results showed that expectations shifted both enjoyment and brain activity.
When participants believed they were drinking a beverage with artificial sweetener, they rated sugar-containing drinks as less pleasant. Conversely, when they believed they were drinking sugar, they rated artificially sweetened drinks as more pleasant.
Brain imaging revealed a similar pattern. When participants received artificial sweetener but expected sugar, researchers observed greater activation in a midbrain region associated with reward processing compared with when participants knowingly received artificial sweetener.
“This could mean that this brain area, the dopaminergic midbrain, processes increased nutrients or calories of sweet flavors,” Westwater said, noting that the finding aligns with animal research linking this brain region to sugar-seeking behavior.
The study highlights how beliefs and learned associations can shape sensory experience. The sweetness itself did not change, but expectations appeared to alter how rewarding it felt.
Importantly, the research does not suggest that artificial sweeteners and sugar are metabolically equivalent or interchangeable from a health standpoint. The study focused on perceived pleasantness and neural response in a laboratory setting, not on long-term dietary outcomes or weight change.
Still, the findings may have implications for how food and beverages are described and marketed.
“If we emphasize that healthier food alternatives are ‘nutrient rich,’ or have ‘minimal added sugars,’ this may create more positive expectations than using terms like ‘diet’ or ‘low calories,’” Westwater said. “This may help people align their food choices with the brain’s preference for calories while supporting behavior change.”
The results add to growing evidence that taste perception is shaped not only by chemistry but also by context. Labels, prior experience and expectation can influence how much people enjoy what they consume.
The study was conducted in young adults with an average age of 24, and it examined short-term reactions during a controlled experimental task. Real-world eating behavior is influenced by many additional factors, including habits, hunger, social context and access to food.
But the research underscores a broader point: enjoyment of sweetness is not determined solely by what is in the cup. The brain’s response appears sensitive to what it anticipates.
For consumers navigating choices between sugar-sweetened and artificially sweetened products, that insight may help explain why some “diet” beverages feel less satisfying and why perception can shift under different framing.
The research was supported by the Bernard Wolfe Health Neuroscience Fund; a Wellcome Trust Investigator Award; a Wellcome Trust Sir Henry Wellcome Postdoctoral Fellowship; and an Academy of Medical Sciences Springboard Award. Research at the University of Cambridge Department of Psychiatry is supported by the NIHR Cambridge Biomedical Research Centre and the NIHR Applied Research Collaboration East of England.