Recent research published in journals Food quality and safety It has been suggested that feeling hungry amplifies the immediate enjoyment of sweet tastes, regardless of whether the sweetness comes from sugar or a zero-calorie alternative. The study also shows evidence that people who regularly consume artificial sweeteners have increased brain activity in areas associated with self-control when tasting sugary drinks. These findings suggest that switching to zero-calorie options may subtly change how the brain processes sweet temptations over time.
Excess sugar intake plays a major role in the development of obesity, type 2 diabetes, and cardiovascular disease. To reduce calorie intake, many people are turning to non-nutritive sweeteners. This is an artificial or plant-based additive that tastes sweet but provides little or no metabolic energy. The widespread use of these low-calorie alternatives has raised questions about how they affect human biology.
Some scientists suggest that consuming sweet tastes without calories can disrupt the body’s natural energy signals. This disruption can change a person’s taste preferences and change how the brain’s reward system responds to food.
Previous long-term trials have yielded mixed results regarding these potential changes. Some reports show that using artificial sweeteners changes a person’s preference for sweet foods, while others say there is no noticeable difference. A factor that can explain these different results is the physical state of your body, especially whether you are hungry or full.
Hunger naturally increases our biological drive for energy, which tends to make high-calorie foods more appealing. Satiety, or the feeling of being full after a meal, suppresses the natural urge to seek food. Physiological state greatly influences eating behavior, so assessing these factors together will allow us to better understand how eating habits shape human food preferences.
The research team included scientists from Jiangnan University in China and Oxford University in the UK. They aimed to understand how metabolic state and habitual sweetener use combine to influence sweet preferences at both conscious and subconscious levels.
To investigate these dynamics, the researchers recruited 30 participants between the ages of 19 and 27. The sample was divided into two equal groups of 15 people each based on their usual dietary habits. One group consisted of habitual sugar consumers who regularly drank sugar-sweetened beverages but rarely used zero-calorie sweeteners. The second group consisted of habitual non-nutritive sweetener consumers who regularly drink zero-calorie options but rarely consume regular sugar.
The experimental procedure required each participant to participate in two separate testing sessions. One session took place when participants were fasting, meaning they had fasted for at least 3.5 hours. The other session took place when they were full, and within an hour of eating a full meal.
During each session, participants tasted three different sweet solutions provided in small 10-ml portions. The three drinks contained a full-sugar solution, a half-sugar solution mixed with a zero-calorie sweetener, and a zero-sugar solution containing only a zero-calorie sweetener. The researchers adjusted all three solutions to have exactly the same level of sweetness, so that participants could not consciously differentiate them based solely on taste intensity.
The test included both explicit and implicit measurements to get a complete picture of participants’ responses. As an explicit measure, participants rated their drink preferences on a 9-point scale. They also completed a questionnaire designed to assess emotional responses, assessing basic emotions such as excitement and comfort. A separate survey provided 25 specific emotional words, allowing participants to build detailed emotional profiles for each drink.
As an implicit measure, scientists monitored participants’ bodies and brains and recorded automatic biological responses. They measured heart rate and nervous system activity using an electrocardiogram, a medical device that records the heart’s electrical signals. They also used functional near-infrared spectroscopy, a non-invasive brain imaging technique that uses light to monitor blood flow and oxygen levels in the brain.
The data show evidence that hunger significantly increased how much participants liked all sugary drinks. Participants consistently gave higher ratings to drinks on an empty stomach than on a full stomach. This increase in enjoyment occurred regardless of whether the drink contained full sugar, half sugar, or no sugar at all.
This particular finding suggests that the physical state of hunger makes the sensory experience of sweetness itself more appealing. It appears that the body does not selectively favor the calorie content of sugar the moment it is tasted. The desire for energy tends to increase the amount of sweet taste, making any sweet sensation highly valuable in the short term.
Electrocardiogram data matched these assessments of consciousness by showing physical signs of wakefulness in the fasted state. When fasting, participants experienced shorter heartbeat intervals and an increase in overall heart rate while sampling the drink. These changes indicate activation of the sympathetic nervous system, a physiological network that triggers the body’s active alarm response.
Brain imaging results reveal clear differences between the two consumer groups. People who habitually consumed zero-calorie sweeteners showed significantly stronger oxygenated blood flow in the left dorsolateral prefrontal cortex compared to those who consumed sugar. This particular area of the brain is deeply involved in cognitive control, dietary self-regulation, and the ability to resist temptation.
This increase in brain activity occurred even though the participants did not know what type of sweetener they were tasting. The two groups also reported similar levels of conscious enjoyment and emotional reactivity. The findings suggest that long-term use of zero-calorie sweeteners may train the brain to engage more self-control and surveillance networks when experiencing sweet tastes.
These results provide practical guidance for public health efforts and the food industry. Hunger increases the appeal of any sweet taste, so replacing sugar in your snacks with artificial sweeteners may satisfy your cravings without adding extra calories. Developing products that are less sweet overall while still remaining satisfying can be a highly effective long-term strategy for reducing sugar intake.
The authors noted several limitations in the experimental design that provide context for these conclusions. This study relied on a relatively small sample size, limiting the ability to generalize the results to a larger population. Some participant data had to be excluded from brain imaging analysis due to reduced signal quality caused by hair occlusion, reducing the sample size for that particular measurement. Sentiment analysis also includes a small sample, so these particular results should be interpreted with caution.
The participant group included significantly more women than men. This imbalance means that the results may not capture potential physiological differences in how men and women process food rewards. Future research projects would benefit from using larger participant groups with equal gender representation.
Another limitation includes the use of self-report questionnaires to determine participants’ eating habits. Self-reports are often subject to memory bias, and people may not remember their sugar and artificial sweetener intake accurately. Future studies could use long-term dietary records or medical biomarkers to more accurately track nutrient intake.
The test environment also lacked real-world food choice context. Participants drank a plain solution from a transparent cup. This eliminated the influence of food packaging, branding, and nutrition labels. In everyday life, knowing that a drink has zero calories can have a significant impact on a person’s expectations and eating behavior.
Future studies could measure actual food consumption after the tasting session and see whether these brain patterns influence how much people eat later in the day. Investigating these factors in a more natural dietary environment can help explain how artificial sweeteners fit into long-term dietary health.
The study was titled “An Exploratory Study of Sweetness Preferences of Habitual Consumers of Sugar and Nonnutritive Sweeteners Revealed by Explicit and Implicit Measures” and was authored by Jiaona Jiang, Fang Zhong, Feifei Xu, Yixun Xia, and Charles Spence.
