Sweet tooth: nature or nurture?

For a healthy diet, it is important to reduce free sugar intake. The World Health Organization (WHO) recommends reducing daily intake of free sugars to less than 10% of total energy intake, with further reduction to less than 5% for additional health benefits. To facilitate this, general advice suggests lowering dietary sweetness to reduce preferences for sweet tastes, which would subsequently lead to reduced sugar intake and improved health. However, the evidence for an association between dietary sweetness and subsequent sweet taste preferences and increased sugar intake is not clear. For example, it is not known whether exposure to diets high or low in sweetness results in a change in sweetness preference and sweet food intake.

In other words, do we get used to a lower sweetness level and therefore automatically choose less sweet-tasting foods? Or do we choose sweeter foods after a period of sweetness reduction?

The Sweet Tooth randomized trial – called i-sense – is a dietary intervention study with partial food provision. It collects data on the effect of 6 months of low, regular, and high sweetness exposure on sweetness preferences, sweetness perception, dietary choice and intake, body weight, and biomarkers for diabetes and cardiovascular disease from 180 adult participants. Currently all data is collected and the first results will be published over the course of 2025.