Telling Someone a Drink Has Sugar Changes How Much They Enjoy It - Even When It Doesn't

The way a food is labeled changes how it tastes. This is not a marketing claim - it is a measurable neurological phenomenon. When people expect a flavor or ingredient, the brain begins processing the anticipated experience before the substance even reaches the taste receptors. That anticipatory processing can amplify, diminish, or redirect the actual sensory signal.

A study published in JNeurosci by Elena Mainetto of Radboud University, Margaret Westwater of the University of Oxford, and colleagues at the University of Cambridge provides a specific and well-controlled example of this effect at work with artificial sweeteners. The findings reveal that expecting sugar in a drink - even when none is present - measurably increases how much a person enjoys that drink, and that the effect involves a specific brain region associated with reward processing.

The Experimental Design

The researchers recruited 99 healthy adults averaging 24 years of age, selecting only participants who reported liking artificial sweeteners and sugar equivalently. This screening step was essential: the experiment needed a starting population without strong prior preferences for one type of sweetener, so that any shift in enjoyment during the study could be attributed to the manipulated expectations rather than to pre-existing attitudes.

Participants received beverages containing either real sugar or artificial sweeteners. Crucially, the labels they saw were sometimes accurate and sometimes deliberately wrong. Some participants received artificially sweetened drinks while being told the drinks contained sugar. Others received sugar-containing drinks while being told the drinks contained artificial sweeteners.

The mismatch between label and content drove clear and measurable changes in enjoyment. When participants falsely believed they were drinking a sugar-containing beverage but were actually consuming artificial sweeteners, their enjoyment of the drink increased compared with a condition in which the label accurately indicated artificial sweeteners. The reverse also held: when the sugar label was removed from an actual sugar drink - when participants expected artificial sweeteners but received sugar - their enjoyment of that drink decreased.

Brain Activation Follows Expectations, Not Content

The neural imaging data added a specific dimension to the behavioral findings. When participants expected sugar and received artificially sweetened beverages, their brains showed increased activation in the dopaminergic midbrain - a region centrally involved in reward processing and motivation. This activation pattern mirrors what the brain typically shows when anticipating a caloric reward.

"This could mean that this brain area, the dopaminergic midbrain, processes increased nutrients or calories of sweet flavors, which supports rodent work showing that this brain region is important for sugar seeking," said Westwater.

The implication is that the brain is not just passively receiving sweetness signals - it is actively predicting caloric content and calibrating its reward response to those predictions. When the prediction is "sugar," the midbrain fires accordingly, even if the actual beverage contains no calories. When the prediction is "artificial sweetener," that reward signal is dampened, even if the drink contains real sugar.

What This Suggests for Dietary Change

The findings have practical implications for how lower-calorie foods and beverages are framed. Current labeling conventions often emphasize what has been removed or reduced - "diet," "sugar-free," "low-calorie" - language that may prime negative expectations and reduce enjoyment. The study suggests that framing these products positively, emphasizing what they contain rather than what has been taken out, might produce more favorable taste experiences.

"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 study used a relatively homogeneous sample of young healthy adults. How these expectancy effects operate in people with different relationships to food - including those with eating disorders, obesity, or strong prior preferences for sweetened products - would require separate investigation. The effects observed here reflect an average across 99 participants; individual variation in expectancy sensitivity could be substantial.