Confusing Opinions with Evidence Yields Scientific Puffery

The attention economy has been getting a lot of, well, attention lately. In fact, the phenomenon is nothing new. People have been competing for the attention of Americans since the rise of cheap daily newspapers in the 19th century. But lately it seems that the quest to command attention is taking over more and more of our lives – perhaps even creeping into the pursuit of science and medicine. It becomes easy to confuse expert opinions with scientific evidence at the risk of producing puffery.

A new letter by Emily Dhurandhar and a long list of nutrition scholars in the American Journal of Clinical Nutrition shines a light on this concern. They point out that a recent advisory on nutrition in the context of GLP-1 therapy takes a step in that direction. Regarding that advisory, they write:

“Use of the terms ‘evidence-based’ and ‘pivotal’ in the abstract conclusion overstates the certainty and strength of the available evidence, blurring the line between expert opinion and evidence-based guidance.”

Expert Guidance

In the publication that prompted this concern, Dariush Mozaffarian and colleagues relied on “limited available evidence and expert opinion to help guide clinicians in addressing real-world questions raised in practice.” This is information that clinicians need.

But the authors of that guidance conclude by saying:

“Evidence-based nutritional and lifestyle strategies play a pivotal role to address key challenges around GLP-1 treatment of obesity, making clinicians more effective in advancing their patients’ health.”

That was a mistake. It blurs the line between evidence and opinion. Perhaps more important, it suggests a “pivotal” role for the guidance in health outcomes. Such a thought is a reasonable opinion, but it is not an evidence-based recommendation.

Scientific Puffery

Keeping a clear distinction between expert opinions and evidence-based guidance is essential for promoting trust in science and medicine. In the attention economy, scientific puffery might be attractive, but it works against credibility. And right now, scientific credibility is under siege.

Click here for the new letter and here for the guidance it references. Other responses to that guidance may be found here and here. The authors of the guidance respond here. For further perspective, click here and here. This subject obviously stirs a lot of interest.

Puff Pastry, photograph by Marc LE PRINCE, licensed under CC BY-SA 3.0

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September 14, 2025