Researchers at Wageningen University in the Netherlands and Bournemouth University in the UK split 180 adults into three groups: a low-sweetness diet, a regular-sweetness diet, and a high-sweetness diet, maintained for six months. The sweetness came from a mix of sources — sugar, naturally sweet foods like fruit and dairy, and low-calorie sweeteners. At one, three, and six months, the team measured sweet preference, weight, blood sugar, and markers of cardiovascular and diabetes risk. The result: no meaningful differences between the groups on any measure, and participants drifted back to their usual sweet intake after the trial ended.
The study's lead authors were direct about the takeaway. "It's not about eating less sweet food to reduce obesity levels," said Katherine Appleton of Bournemouth University. "The health concerns relate to sugar consumption." Some foods that taste sweet — fruit and dairy — are associated with health benefits, while some fast-food items that do not taste sweet at all contain high levels of sugar. The distinction matters because much public health advice has focused on sweetness rather than sugar.
For stone patients, the Sweet Tooth Trial lands on a familiar tension: the stone diet already limits sugar-sweetened beverages and high-oxalate sweets, but the reason has always been about sugar and oxalate, not about "training" the palate. The trial's finding that sweetness preference does not shift with intake is actually good news for patients — it means a stone-safe diet does not need to make desserts taste less appealing over time to work. What the diet needs to control is the sugar and the oxalate columns, which are measurable and stable.
The sweet items on the stone table split into two groups. Dairy-based sweets — milk, yogurt, and ice cream made with real dairy — deliver calcium that binds oxalate while tasting sweet. Fruit-based desserts like peach crisp and apple pie measure low oxalate and add fiber. The items to manage are the sugar-heavy, oxalate-concentrated ones: chocolate measures about 61 mg of oxalate per ounce (caution range), and sweetened berry pies concentrate both sugar and oxalate. The trial's logic — control sugar, not sweetness — maps directly onto that measured list.
The table below separates the common sweet items by their measured oxalate, which is the column that matters for stones. The trial reminds us that the sugar column matters for general health, and the oxalate column matters for stone risk — and the two do not always move together.
| Food | Oxalate (mg) | Serving | Rating |
|---|---|---|---|
| Milk, cow's | 0 | 1 cup | Safe |
| Greek yogurt, plain | 0 | 1 cup | Safe |
| Peaches, fresh | 3 | 1/2 cup | Safe |
| Apples, fresh | 2 | 1 medium | Safe |
| Bananas | 6 | 1 medium | Safe |
| Chocolate, dark | 61 | 1 oz | Caution |
| Blueberries, fresh | 27 | 1 cup | Caution |
| Blackberries, fresh | 45 | 1 cup | Caution |
The practical translation for stone patients: keep the sugar-sweetened beverages limited (they add sugar and displace water and milk), keep the dairy at meals for calcium, and treat the high-oxalate sweets — chocolate, nut-heavy treats, berry pies without dairy — as portioned items rather than daily staples. Do not expect the cravings to disappear, and do not treat a craving as a failure. The trial's six-month finding is that preference is stable; the stone plan does not need preference to change, only portions and pairing to hold.
One more measured point from the trial applies directly: participants naturally returned to their usual sweet intake after the intervention ended. For stone patients, that means the diet's durability depends on structure — the dairy-first plate, the water bottle, the portioned dessert — rather than on any single food being "off limits." A stone plan that survives the natural return of sweet cravings is a plan built on defaults, not on willpower.
No. The trial found that reducing sweet-tasting foods did not change cravings or health markers — the concern is sugar and energy-dense foods, not sweetness itself. For stones, the measured issue remains what it always was: sugar-sweetened drinks displace water and milk, and high-oxalate sweets add to the oxalate column.
Yes, measured. Dairy sweets (milk, yogurt) deliver calcium and taste sweet; fruit desserts are mostly low-oxalate. The items to portion are chocolate (61 mg/oz, caution), berry-heavy pies, and any nut-and-sugar treat. Portions and dairy pairing carry the plan.
According to this trial, cutting sweet foods may not reduce cravings — preference appears stable over six months. The stone plan does not depend on cravings disappearing; it depends on structure: dairy at meals, water as the drink, and sweets as measured portions.
See how oxalate values are measured and verified on our data methodology page.