What Is “The Sweet Tooth Trial”?
For years, public health guidelines have operated under the assumption that cutting back on sweet-tasting foods will retrain the palate, lower cravings for sweetness, and ultimately reduce calorie and sugar intake.
To test this “sweet tooth” hypothesis, researchers at Wageningen University & Research in the Netherlands and Bournemouth University in the UK conducted a comprehensive 180-participant clinical trial published in the American Journal of Clinical Nutrition.
Study Overview & Methodology:
- Participants: 180 healthy adults divided into three distinct dietary groups.
- Duration: 6-month dietary intervention followed by a 4-month post-trial follow-up.
- Controlled Exposure: Provided foods making up ~50% of daily energy needs tailored to specific sweetness exposure levels:
- Low Sweetness Group (7% sweet foods)
- Regular Sweetness Group (35% sweet foods)
- High Sweetness Group (80% sweet foods)
- Sources of Sweetness: Sweetness came from a combination of natural sugars (fruit, dairy), added sugars, and low-calorie artificial sweeteners.
Key Findings: Why Dietary Sweetness Doesn’t Retrain Your Palate
The study tracked sensory perception, food choices, calorie intake, body weight, and blood/urine biomarkers for diabetes and cardiovascular disease across the six-month period.
Dietary Sweetness Intervention (6 Months)
├── Low Exposure (7%) ──> No Change in Sweet Liking / No Weight Loss
├── Regular (35%) ──> No Change in Sweet Liking / Baseline Health
└── High Exposure (80%) ──> No Change in Sweet Liking / No Health Risk Increase1. Sweet Preferences Remain Remarkably Stable
Despite major differences in daily sweetness exposure, participants in the low-sweetness group liked sweet foods just as much after six months as those in the high-sweetness group. Furthermore, their perception of sweetness intensity did not change.
2. No Effect on Heart Health or Diabetes Biomarkers
Blood and urine tests revealed no meaningful differences in blood glucose, insulin, HbA1c, or cholesterol levels among participants on high, low, or average sweetness diets.
3. Spontaneous Return to Baseline
Once the six-month intervention concluded, participants across all groups naturally reverted to their original dietary sweetness preferences.
Experts Call for Rethinking Obesity & Sugar Advice
The trial’s authors argue that public health messaging needs to pivot away from targeting general “sweetness” and focus specifically on added sugar and calorie density.
“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. 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.”
— Professor Katherine Appleton, Corresponding Author & Psychology Professor at Bournemouth University
Nutritional Distinction: Sweetness vs. Sugar
The study emphasizes that judging food based purely on sweet taste overlooks critical nutritional differences between whole foods, low-calorie options, and ultra-processed items.
| Food Source | Sweetness Origin | Additional Nutritional Value | Impact on Health & Satiety |
|---|---|---|---|
| Fresh Fruit & Dairy | Naturally occurring sugars | High (Fiber, vitamins, minerals, protein) | Beneficial; promotes fullness and overall health |
| Diet / Zero-Calorie Items | Non-nutritive sweeteners | Variable | Provides sweet taste without added calorie density |
| Ultra-Processed Sweets | Added refined sugars | Low / Minimal | High energy density; risk factor for weight gain |
| Savoriness/Fast Food | Refined carbohydrates & fats | Low (Often hidden added sugars) | High calorie density despite lacking a sweet taste |
Key Takeaway: Professor Appleton highlights that public health campaigns should prioritize helping individuals reduce energy-dense, high-sugar foods—some of which may not even taste overtly sweet—rather than demonizing all sweet-tasting items.
sweet taste preference study. Sweet Tooth Trial, reducing sweet foods obesity, Bournemouth University sweetness study, American Journal of Clinical Nutrition, Katherine Appleton.
