Highlights
No Palate Retraining
Six months of strictly controlled low, regular, or high dietary exposure to sweet taste did not lead to any significant changes in sweet taste liking or intensity perception among healthy adults.
Weight and Metabolic Stability
Despite significant differences in the percentage of sweet-tasting foods consumed, there were no significant group differences in body weight, energy intake, or markers for diabetes and cardiovascular disease.
Reversion to Baseline
Once the intervention concluded, participants in all groups spontaneously returned to their baseline levels of sweet food consumption, suggesting that temporary exposure changes do not permanently shift dietary habits.
Background: The Exposure-Preference Hypothesis
For decades, public health organizations and clinical nutritionists have operated under the assumption that human preference for sweetness is plastic and highly dependent on recent exposure. The prevailing narrative suggests that by reducing the consumption of sweet-tasting foods—whether sweetened with sugars or low-calorie sweeteners (LCS)—individuals can effectively retrain their palates. The theoretical end goal is a reduced craving for sweetness, leading to lower sugar intake, reduced caloric consumption, and improved outcomes in obesity prevention and metabolic health.
However, this paradigm has largely been built on observational data or short-term sensory studies. Empirical, long-term evidence from randomized controlled trials (RCTs) has been strikingly absent. The Sweet Tooth Trial was designed to fill this critical gap in evidence-based nutrition by investigating whether a sustained, six-month alteration in dietary sweet taste exposure actually translates into measurable changes in sensory perception, food choice, and clinical health markers.
Study Design: The Sweet Tooth Trial
Methodology and Population
In this parallel-groups randomized controlled intervention study, researchers recruited 180 healthy adults. The cohort was characterized by a mean age of 35 ± 15 years and a mean body mass index (BMI) of 23 ± 3 kg/m2, representing a lean, healthy population. The participants were randomized into three distinct groups based on the level of sweet taste exposure provided in their daily diet for a duration of six months.
The Intervention Armaments
Participants were provided with dietary advice and approximately 50% of their daily energy needs in the form of specific foods and beverages. The groups were categorized as follows:
1. Low Sweet Taste Exposure (n = 61): Only 7% of provided foods and beverages were sweet-tasting.
2. Regular Sweet Taste Exposure (n = 60): 35% of provided items were sweet-tasting.
3. High Sweet Taste Exposure (n = 59): 80% of provided items were sweet-tasting.
The sweetness in these diets was derived from a variety of sources, including natural sugars, low-calorie sweeteners, fruits, and dairy products. To ensure compliance, researchers utilized self-reported dietary measures and objective urinary markers for sucrose, sucralose, and saccharin.
Clinical Endpoints
Assessments were conducted at baseline, at the 6-month mark (end of intervention), and at a 4-month follow-up. The primary outcomes included sweet taste liking and sweet taste intensity perception. Secondary outcomes encompassed food choice, total energy intake, body weight, and various biomarkers for diabetes and cardiovascular disease (CVD).
Key Findings: A Lack of Sensory and Metabolic Shift
Sensory Perception and Liking
Despite the rigorous and prolonged nature of the intervention, the results were definitive: altering exposure to sweet-tasting foods did not change sweet taste liking. The statistical analysis showed no significant differences between the low, regular, and high exposure groups (χ2(40) = 37.9, P = 0.56). Similarly, sweet taste intensity perception remained stable across all cohorts (χ2(40) = 20.7, P = 0.99). These findings suggest that the human sensory response to sweetness may be more biologically innate or resistant to dietary modification than previously hypothesized.
Food Choice and Energy Intake
There was no evidence that reducing sweet exposure led to a subsequent ‘rejection’ of sweet foods or a preference for savory options. Sweet food choice remained consistent across groups at the 6-month mark (χ2(10) = 10.1, P = 0.43). Furthermore, energy intake did not significantly deviate between the groups, suggesting that the level of sweetness in the diet—independent of energy density—does not inherently drive overconsumption or caloric restriction in a controlled setting.
Metabolic Health and Weight Status
From a clinical perspective, the most notable findings were the lack of impact on weight and metabolic markers. Body weight remained stable across the three intervention arms (χ2(10) = 14.3, P = 0.16). Markers for diabetes (such as fasting glucose and HbA1c) and cardiovascular disease (lipid profiles and blood pressure) showed no significant changes related to the degree of sweet exposure. This suggests that sweetness, as a sensory property, may not be the primary driver of metabolic dysfunction when energy intake is otherwise managed.
Post-Intervention Behavior
One of the most telling aspects of the study was the 4-month follow-up. Once the provided diet and dietary advice were removed, participants in the low-exposure group did not maintain their reduced sweet intake. Instead, they spontaneously returned to their baseline levels of sweet food consumption. This indicates that a six-month ‘detox’ or reduction period is insufficient to override long-term dietary habits or hedonic preferences.
Expert Commentary and Clinical Implications
Challenging Public Health Narratives
The Sweet Tooth Trial provides high-quality evidence that directly contradicts several public health guidelines. Many organizations currently advocate for a reduction in all sweet-tasting substances to help patients ‘lose their sweet tooth.’ These results suggest that such advice may be ineffective if the goal is to permanently alter taste preferences. Clinicians should be cautious about promising patients that their cravings for sweets will disappear if they simply avoid them for a few months.
Energy Density vs. Sweet Taste
It is vital to distinguish between sweet taste as a sensory attribute and the energy density of the foods providing that taste. The trial suggests that sweetness itself—whether from a piece of fruit or a diet soda—does not necessarily trigger physiological changes in liking or weight status. Future dietary strategies may need to focus more on the nutritional quality and caloric density of foods rather than focusing solely on the sensory profile of sweetness.
Study Limitations
While the study was well-powered and rigorously conducted, it focused on healthy, relatively lean adults. It remains to be seen if these results would differ in populations with obesity, type 2 diabetes, or those with established eating disorders. Additionally, the study provided 50% of energy needs; while this is a significant portion, the remaining 50% was subject to the participants’ own choices, though compliance markers remained strong.
Conclusion: Rethinking Dietary Guidance
In conclusion, the Sweet Tooth Trial demonstrates that a 6-month intervention of low, regular, or high sweet taste exposure does not alter sweet taste liking, intensity perception, energy intake, or body weight. These findings do not support the common public health recommendation that reducing exposure to sweet-tasting foods will decrease the preference for such foods or aid in obesity prevention. For healthcare providers, the focus should perhaps shift from the ‘retraining the palate’ narrative toward more holistic approaches to energy balance and the consumption of nutrient-dense whole foods, regardless of their sweetness.
Funding and ClinicalTrials.gov
This research was supported by grants from relevant nutritional and health research councils. The trial was registered at clinicaltrials.gov as NCT04497974.
References
1. Čad EM, Mars M, Pretorius L, van der Kruijssen M, Tang CS, de Jong HB, Balvers M, Appleton KM, de Graaf K. The Sweet Tooth Trial: A Parallel Randomized Controlled Trial Investigating the Effects of A 6-Month Low, Regular, or High Dietary Sweet Taste Exposure on Sweet Taste Liking, and Various Outcomes Related to Food Intake and Weight Status. Am J Clin Nutr. 2026 Jan;123(1):101073. doi: 10.1016/j.ajcnut.2025.09.041.
2. Appleton KM, Tuorila H, Bertenshaw EJ, de Graaf C, Mela DJ. Sweet taste exposure and the subsequent acceptance and preference for sweet taste in the diet: systematic review of the published literature. Am J Clin Nutr. 2018;107(3):405-419.
3. Public Health England. Sugar Reduction: Responding to the Challenge. London: PHE Publications; 2014.
