The World Health Organization (WHO) recently issued a “conditional recommendation” on non-sugar sweeteners (NSS), sparking discussions and concerns regarding their potential impact on human health. This guideline is based on a comprehensive systematic review of Randomized Controlled Trials (RCTs) and particularly observational studies, which advises against using NNS for weight control. Considering the limitations of available evidence and the need for further research, it is important to take a balanced perspective on the WHO recommendation on NSS. We asked Michelle Pang, a PhD-student at Maastricht University involved in WP3 of the SWEET H2020 Project to discuss the SWEET consortium position on the WHO guideline on NNS.

Conditional Recommendations and Limited Evidence:

Interpreting the meaning of “conditional recommendation” is vital when understanding the WHO guidelines on NNS. These guidelines acknowledge the limitations of the available evidence to draw definitive conclusions. The phrase “conditional recommendations” is used when the research reviewed does not unequivocally demonstrate that the benefits of NSS outweigh any negative effects. This highlights the need for further research to gain a clearer and more robust understanding of the impact of NSS on human health.

Observational Evidence vs. Short-term RCTs:

Existing observational evidence has raised concerns about potential negative associations between NSS intake and health outcomes. Considering the possibility of reverse causation in these studies is crucial, as individuals at elevated disease risk might initiate or increase their NSS use due to their risk status, rather than NSS causing increased risk in otherwise healthy individuals. Some studies indicate that NSS users have a higher prevalence of relevant risk factors, such as pre-existing overweight and obesity, which are associated with adverse outcomes. Conversely, short-term RCTs more often show neutral or positive effects on various health outcomes. However, the short-term nature of these RCTs limits their ability to comprehensively address the long-term consequences of NSS consumption.
Importance of Longer-term RCTs:
Within the context of ongoing research, Michelle Pang, highlights the importance of investigating longer-term effects. WP3 specifically focuses on conducting comprehensive RCTs to understand the lasting consequences of NNS consumption on body weight control and the risk on noncommunicable diseases (NCDs). By carrying out these longer-term studies, WP3 contributes to building a more reliable knowledge base, potentially assisting the WHO and policymakers in formulating evidence-based guidelines.


Due to uncertainties regarding risks and beneficial effects, the guideline on NNS is positioned as a “conditional recommendation”. However, the guideline is based on limited evidence, necessitating further research to fully understand the impact of NSS on human health.

Maintaining a balanced perspective and avoiding sensationalism is essential as we await more conclusive findings. The ongoing activities within the SWEET Project contribute to our understanding of NSS, but additional research will be required even after the project concludes. Media characterization of the WHO guideline should be approached critically, as it can sway public opinion and NSS adoption. By keeping informed and remaining open to results from further research, we can make more informed decisions about NSS consumption and its potential role in promoting overall well-being.

The WHO guideline is available for download via the WHO website: 

EU Flag icon

The project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 774293. The material presented and views expressed here are the responsibility of the author(s) only. The EU Commission takes no responsibility for any use made of the information set out.