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Regular Fasting May Boost Heart Health


2 Star


Regular Fasting May Boost Heart Health

Our Review Summary

This story hinted at other factors that might explain the statistical association – but didn’t drive home the limitations of an observational study. It also didn’t point out that such a cross-sectional study (the exposure – fasting – and the outcome – coronary artery disease, as measured by angiography – were measured at the same time) can’t draw any conclusions about causality.

Single source stories like this – from a team promoting its current and past line of research – demands independent perspectives.  But this story didn’t provide any.


Why This Matters

Stories about talks at scientific meetings require caveats because the data has not undergone rigorous peer review.

Stories about observational studies require more explanation and more careful language than provided in this story.


Does the story adequately discuss the costs of the intervention?

Not Applicable

Not applicable.  Cost of fasting not an issue.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The story states that “people who fasted regularly had a 58 percent lower risk of coronary disease compared with those who said they didn’t fast.”  But 58% of what?  The story could have noted baseline risk in the general population or in people diagnosed with coronary heart disease.  But even in the latter category, that’s a very wide spectrum of disease.  All of which shows how the 58% figure lacks any context for readers.

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

The only discussion of potential harms of fasting was this: “Any fast should include water because dehydration can raise risk for stroke.”  Over what period of time?  What’s the evidence base?  In what kinds of people? What could happen if people at risk for cardiovascular disease, such as diabetics, fast?

Even the previous line in the story suggests a broader issue than that when it said “fasting is causing some major stress.”  What does that mean, and what are the broader implications for potential harms?

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

Mixed bag, but the negatives outweighed the positives.

Good point:

  • The story stated that “the study showed only an association between fasting and better heart health, which means it’s possible that fasting may not have a direct effect.”

Followed by a weak point:

  • The story went on to say that a second smaller study suggests that the “effects of fasting…”  But wait. Observational studies can’t prove cause and effect – a statement that should have been made more strongly.  Yet this followup sentence seems to want to affirm that there were, indeed, established “effects of fasting.”

The story also never mentioned the inherent limitations in drawing conclusions from a study of 30 people over 24 hours’ time.  Nor did it mention that this conference presentation had not yet undergone rigorous peer review.

Does the story commit disease-mongering?


No overt disease mongering.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

No independent expert was quoted, something sorely lacking in the story.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

Another mixed bag, but with a confusing message that warrants an unsatisfactory grade.

The story points out that one of the limitations in the study may have been that its subjects – Mormons – abstain from alcohol, smoking and caffeine – all factors that could affect heart health.

But later in the story it allows the researcher to say “what it does suggest is that fasting is not a marker for other healthy lifestyle behaviors.”

Huh?  That seems to convey some independent protective effect that the study simply can’t prove.  And it seems to minimize the other confounding factors acknowledged earlier in the story.

Does the story establish the true novelty of the approach?


The story at least noted that the same research team published an earlier, larger study in 2008.

Does the story appear to rely solely or largely on a news release?


The story appears to have included an interview with the researcher, so we think it’s unlikely that it relied solely on a news release.

Total Score: 3 of 8 Satisfactory


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