A randomized trial of 180 adults found that substantially increasing or decreasing exposure to sweet-tasting foods for six months did not significantly change participants’ preference for sweetness, body weight, energy intake or measured markers of diabetes and cardiovascular risk.
By yourNEWS Media Newsroom.
Reducing how much sweet-tasting food people eat may not diminish their preference for sweetness or produce measurable improvements in weight and cardiometabolic health, according to a six-month randomized controlled trial that challenges the idea that people can weaken a “sweet tooth” simply by eating fewer sweet foods.
Researchers from Wageningen University and Research in the Netherlands and Bournemouth University in the United Kingdom randomly assigned 180 healthy adults to diets containing low, regular or high levels of sweet-tasting foods and beverages.
After six months, investigators found no statistically significant differences among the groups in sweet taste preference, perceived sweetness, selection of sweet foods, energy intake, body weight, or biomarkers associated with diabetes and cardiovascular disease. The groups also did not differ significantly in adverse events.
The study, called the Sweet Tooth Trial, was published online Nov. 27, 2025, and appeared in the January 2026 issue of the American Journal of Clinical Nutrition. Researchers said the results call into question dietary recommendations based on the premise that frequent exposure to sweetness strengthens a person’s preference for sweet foods and subsequently increases sugar consumption, calorie intake and body weight.
“People have a natural love of sweet taste which has led many organizations, including the World Health Organization, to offer dietary advice on reducing the amount of sweetness in our diets altogether,” said Katherine Appleton, professor of psychology at Bournemouth University and corresponding author for the study. “However, our results do not support this advice, which does not consider whether the sweet taste comes from sugar, low-calorie sweeteners, or natural sources.”
The distinction between sweetness and sugar was central to the research.
Foods in the trial derived their sweet taste from several sources, including sugar, fruit and dairy products, and low-calorie sweeteners. Researchers were testing exposure to sweet taste itself rather than whether consuming more or less added sugar improves health.
That distinction is important because the study does not conclude that diets high in added sugar are harmless. The World Health Organization continues to recommend that adults and children limit free sugars to less than 10% of total energy intake and suggests reducing them below 5% for additional health benefits. WHO’s recommendations are based in part on evidence concerning unhealthy weight gain and dental disease.
WHO has separately advised against relying on non-sugar sweeteners for long-term weight control and stated in its 2023 guidance that people should consider reducing the overall sweetness of their diets. That latter assumption — that reducing exposure to sweetness itself could alter preferences and health outcomes — is what the Sweet Tooth Trial directly tested.
The 180 participants included 123 women and 57 men. Their average age was 35, and their average body mass index was approximately 23, placing the typical participant within the normal-weight range. Participants were healthy, Dutch-speaking adults between 18 and 65 years old.
Researchers divided them into three approximately equal groups: 61 participants received the low-sweetness intervention, 60 were assigned to regular sweetness and 59 to high sweetness.
The researchers supplied approximately half of participants’ daily energy needs and gave them dietary plans for the remainder.
In the low-sweetness group, about 7% of the supplied foods and beverages were sweet-tasting. That proportion rose to about 35% in the regular-sweetness group and 80% in the high-sweetness group. Participants were advised to obtain approximately 10% to 15% of their overall energy from sweet foods in the low-exposure group, 25% to 30% in the regular group and 40% to 45% in the high group.
The foods were commercially available products rather than specially formulated laboratory meals. Examples ranged from nuts, crackers and savory spreads to fruit, yogurt products, chocolate, jams and sweetened beverages.
Researchers intentionally designed the diets to be comparable in overall energy, energy density, macronutrient composition and food form. That allowed them to examine sweetness exposure while reducing the likelihood that major differences in calories, fat, protein or other dietary characteristics would explain the results.
Participants were assessed repeatedly during the intervention and after it ended. The research schedule included visits at baseline and at one, three and six months, followed by assessments one and four months after completion of the intervention.
Researchers used several methods to determine whether participants’ preferences changed.
Participants tasted familiar and unfamiliar foods and beverages at different levels of sweetness. Test foods included flavored lemonades, custards and cakes prepared in five sweetness concentrations. Participants rated how much they liked the samples and how sweet they perceived them to be.
Investigators also measured food choices and energy intake, recorded body weight and collected blood and urine samples to examine biomarkers related to diabetes and cardiovascular health.
The dietary intervention succeeded in creating substantially different levels of sweet-food consumption among the three groups. Both self-reported dietary measurements and urinary biomarkers confirmed that participants were exposed to different amounts of sweet foods during the intervention.
Those differences in exposure, however, did not produce corresponding differences in the principal outcomes.
People consuming the high-sweetness diet did not become significantly more fond of sweet tastes. Participants assigned to sharply reduce their exposure did not develop a significantly weaker preference for sweetness.
Researchers likewise found no significant between-group effect on how intensely participants perceived sweetness or on which sweet foods they selected.
There was also no significant difference in energy intake or body weight after six months.
Blood and urine measurements used to examine indicators associated with diabetes and cardiovascular health similarly showed no significant overall difference attributable to the level of sweet taste exposure.
Of the 180 people initially randomized, 163 completed the six-month intervention and 159 completed the four-month follow-up, according to the published study. Dropout rates did not differ significantly among the groups.
Another finding emerged after researchers stopped directing participants’ diets: people tended to return spontaneously toward the amount of sweet food they had consumed before entering the trial.
That return toward baseline occurred regardless of whether participants had spent six months eating a diet deliberately designed to be much sweeter or much less sweet. Researchers said the pattern provided additional evidence that prolonged exposure alone did not permanently reset sweet-food preferences.
The results build on earlier work by the research group. Bournemouth University researchers previously reported little evidence that changing exposure to sweetness alters preferences for other sweet foods, including shorter interventions involving sweet versus nonsweet breakfasts and temporary increases or decreases in sweet-food intake.
Appleton said the latest findings indicate that dietary advice should distinguish between a food’s taste and its nutritional composition.
“Our results do not support this advice,” Appleton said of recommendations to reduce sweetness overall.
She emphasized that a food’s perceived sweetness is not a reliable measure of how much sugar or energy it provides.
“It’s not about eating less sweet food to reduce obesity levels,” Appleton said. “The health concerns relate to sugar consumption. Some fast-food items may not taste sweet but can contain high levels of sugar. Similarly, many naturally sweet products such as fresh fruit and dairy products can have health benefits. Public advice therefore needs to concentrate on how people can reduce the amount of sugar and energy-dense foods they consume.”
WHO guidance similarly distinguishes naturally occurring sugars in whole foods from free sugars and recommends fresh fruit as an alternative to foods containing large quantities of added or free sugars.
The trial also does not resolve broader questions surrounding individual low-calorie sweeteners.
WHO’s 2023 recommendation against using non-sugar sweeteners for weight control was based on a separate body of research examining long-term health outcomes. WHO classified that recommendation as conditional because associations found in observational research could partly reflect characteristics of people who choose to use sweeteners rather than effects caused by the sweeteners themselves.
The Sweet Tooth Trial instead examined whether exposure to sweet taste — regardless of whether it came from sugar, low-calorie sweeteners or naturally sweet foods — changes preference, intake and selected health measures.
Researchers cautioned that their participants were generally healthy and relatively lean, with an average BMI of 23. The findings therefore cannot establish that the same results would necessarily occur among people with obesity, diabetes or other metabolic conditions.
The authors also noted that the intervention provided about half of participants’ food and that participants otherwise continued living normally rather than residing in a controlled research facility.
Still, the trial’s randomized design, six-month duration, objective measures of dietary compliance and follow-up period allowed researchers to test directly a dietary assumption that had previously been supported by relatively little long-term experimental evidence.
The authors concluded that changing exposure to sweet-tasting foods alone did not alter sweet preference or the other measured outcomes and said their findings do not support recommending lower sweet-taste exposure independently of factors such as a food’s calorie density and physical form.
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