Project
Sweet tooth: nature or nurture?
In the Western food environment, overconsumption is prevalent. Reducing dietary sweetness is a recommended strategy to lower energy intake. This project investigated the impact of dietary sweetness exposure on sweet taste preferences.
For a healthy diet, it is important to reduce free sugar intake. 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. 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 – was a dietary intervention study with partial food provision. It collected 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.
The study shows that people who followed a low-sweetness diet for six months remained just as fond of sweet as before. Those who consumed extra-sweet foods did not grow to like sweet flavours more. Also no effects were found on body weight and markers associated with diabetes and cardiovascular disease.
‘Our sweet taste preference turns out to be more stubborn than thought,’ concludes PhD student Eva Čad. The trick to temper your sweet tooth by temporarily cutting down on sugar and sweeteners does not seem to work after all. Read the full article here Lees het volledige artikel hier.
Eva Marija Čad will defend her PhD thesis on this research on Friday 13 June at Wageningen University & Research (Division of Human Nutrition and Health).
Frequently Asked Questions (FAQ)
Why was the Sweet Tooth study done?
Many people believe that the more we eat or drink sweet-tasting things, the more we crave and consume sweetness or, in other words, grow a “sweet tooth”. This common belief is also echoed by several public health organizations that recommend cutting back on sweet-tasting foods in our diets, regardless whether the sweetness comes from sugar or sugar substitutes, like low-calorie sweeteners. 1,2,3,4
The idea is that reducing intake of sweetness lowers our preference for sweetness, ultimately helping us consume less sugar and fewer calories — an important step in preventing obesity.
However, scientific support for this narrative is limited and not consistent in its findings. Most studies are short term and suggest a lower preference for sweet taste after sweet exposure, possible due to sensory satiety. On long term there are limited effects shown. Studies are often small and did not define taste exposure very well.
The sweet tooth study was performed to give an answer to the question whether sweetness consumption affects our liking for sweetness.
References
What was the main research?
What other questions can be answered?
Does consuming more↑ or less↓ sweet-tasting foods and drinks for 6 months impact how we perceive sweetness and what we choose to eat?
How does it affect body weight and blood markers related to heart disease and diabetes?
What did the Sweet Tooth study find?
Changing how many sweet-tasting foods and drinks we consume does not affect our preference for sweetness.
The study also did not show an effect on energy intake or on body weight or blood markers for diabetes and heart disease.
What are the implications of the Sweet Tooth study results?
The common belief that eating or drinking more sweet-tasting things leads to stronger cravings for sweetness over time – the “sweet tooth” effect – is not confirmed.
The idea that cutting back on sweet-tasting foods and drinks shifts our food preferences or choices over time is not supported and not likely to be an effective strategy. The advice to reduce the risk of overconsumption by lowering exposure to sweetness – regardless of source - should be re-evaluated.
To improve health recommendations, we encourage policymakers and other influencers in society to focus on evidence based dietary advice. Such as, regulating energy intake by favouring smaller portions and foods with a low energy intake rate, supporting satiety without excess calories.
What was the intervention like?
How did you change the sweetness of the 3 different diets?
The participants either received foods that were:
* not sweet tasting (low sweet group, 14% energy from sweet tasting foods),
* only foods that were sweet tasting (high sweet group, 27,2%), or
* a combination of the two (regular sweet group, 20,5)
How do you know whether people really ate the foods you provided?
What is the average sweet-tasting food intake in the Netherlands?
Is sweetness liking related to sweet food intake?
No, liking a sweet taste does not necessarily mean that someone eats a lot of sweet-tasting foods.
https://www.wur.nl/en/publication-details.htm?publicationId=bf4d7a7f-8ea1-4272-b90d-9bb366f9757c
How was the study funded?
The study received funding from both public institutions and private companies (TKI-AF-17107).
The study was conducted under the TiFN framework, now Next Food Collective, which facilitates public–private partnerships while ensuring compliance with ethical standards. To prevent any conflicts of interests special attention went to the governance of the project, including an advisory and a steering committee.
Advisory committee: The private funders were part of an Advisory Committee, they did not have decision-making power over the study's design or results. The members were: American Beverage Association, Apura Ingredients, Arla Foods, Cargill, Cosun Nutrition Center, DSM-Firmenich, International Sweeteners Association, SinoSweet Co., Ltd, and Unilever Foods Innovation Centre Wageningen.
Steering committee: An independent Steering Committee had the authority to approve study protocols and publications, helping to manage potential conflicts of interest. This committee included experts from universities (Leeds and Copenhagen), France's National Research Institute for Agriculture, Food and Environment (INRAE), the Dutch Institute of Public Health (RIVM), and the Dutch Diabetes Fund. They provided binding advice on the study's design, execution, and reporting to ensure scientific integrity.
Was the study protocol and the analyses pre-registered?
Was the study monitored?
Was the study approved by an ethical committee?
registration number NL72134.081.19.
Did participants experience any weight changes or health issues from eating more sweet-tasting foods?
Does this mean it is healthy to eat sweet foods?
No, this does not mean that it is healthy to eat sweet foods.
We tested the effect of sweet tasting foods and our primary interest was a change in preference.
We measured a limited number of health related outcomes, so we cannot rule out any effects of the sugar or sweeteners on other health related outcomes than the ones we measured.
We refer to the national dietary guidelines to eat a balance and varied diet, for the Netherlands these are the dietary guidelines of the Health council1, translated into public dietary advice by the nutrition centre.
1 Dutch dietary guidelines 2015 | Advisory report | The Health Council of the Netherlands