We read with interest the Comment article by Kimber Stanhope (Guidelines to lower intake of added sugar are necessary and justified. Nat. Rev. Cardiol. 19, 569–570 (2022))1, in which she criticized our recent narrative review2. We feel that our views were misrepresented and would like to clarify them.

Our original intention was to call for caution regarding the over-extrapolation of results from studies on sugar-sweetened beverages (SSBs), as Dr Stanhope correctly stated1. However, we did not intend to exonerate added sugars as being harmless to health. We were pointing out that most, if not all, the available evidence linking added sugars to ill health comes from studies on SSBs. If we follow the principles of evidence-based medicine3, the appropriate conclusion to draw is that added or free sugars from SSBs are harmful to health — and no more than that. Extrapolating results from SSB studies to demonize all forms of added sugars is not evidence-based but, instead, best guess. Even if it is the most logical line of thought, one should not ‘sugar coat’ such extrapolation as being evidence-based.

Dr Stanhope also claimed that we did not outline the potential negative consequences of a recommendation to reduce the intake of added or free sugars to <10% of daily energy intake1. However, we did point out in our review the possible negative consequences of blanket reductions of added or free sugars in the food supply2, such as increased exposure to artificial sweeteners in non-low-calorie products4 and the nutrient dilution effect of a stringent diet that is low in added or free sugars5, which Dr Stanhope overlooked.

Evidence gathered to inform the World Health Organization (WHO) guidelines demonstrates that both solid and liquid sources of added sugars cause dental caries6. However, articles from peer-reviewed journals and the popular media that cite the WHO guidelines generally refer to the guidelines in the context of reducing the risk of being overweight or obese and rarely mention that the WHO itself concluded that the evidence linking added sugar to being overweight or obese was of only moderate to low quality7. Indeed, the WHO contradicted this conclusion from the quality-of-evidence assessment and stated that “reducing free sugars intake to less than 10% of total energy” is a strong recommendation. Of note, the quality-of-evidence assessment used by the WHO was based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach that Dr Stanhope criticized Erickson and colleagues8 for using to conclude that the evidence underpinning the WHO guidelines was of low quality.

We looked at the publisher’s website for the article reviewing studies from >40 years ago9 to which Dr Stanhope referred, but we were unable to locate it. Nonetheless, if opposing results can be found only in an article that was published in 1985 (and no newer studies have shown similar findings), perhaps it is appropriate to say that its omission did not drastically affect the conclusion of our review.

In summary, we would like to reiterate that we agree that added or free sugars from SSBs should be reduced, given that the evidence has consistently shown an association between SSBs and ill health10. We remain sceptical about the quality of the evidence (if any) on the reduction of added or free sugars from all types of food, especially solid foods, to improve overall health.

There is a reply to this letter by Stanhope, K. L. Nat. Rev. Cardiol. https://doi.org/10.1038/s41569-022-00793-8 (2022).