KenDBerryMD - BEWARE: Fasting is Dangerous? [American Heart press release] - 2026

Short Summary

Main recommendation: Dr. KenDBerry argues that the American Heart Association's press release linking intermittent fasting to higher cardiovascular death risk is not credible, and that longer fasts are not dangerous and may be one of the healthiest things you can do. He bases this on the claim that the underlying poster presentation is unpeer-reviewed, unpublished, and built on weak observational data.

Key Points

• The source is a poster presentation at an American Heart Association event, not a peer-reviewed or published study, and the speaker says it should not have been treated as a study.
• The analysis used NHANES data from roughly 2003 to 2014 or 2018, when intermittent fasting was not a common practice, and relied on food frequency questionnaires asking participants to recall what they ate up to a year earlier.
• The reported hazard ratio for cardiovascular death was 1.91 for people fasting 16 or more hours a day, which the speaker says is a weak association in epidemiology, while the study found no increase in all-cause mortality.
• The speaker argues the fasting group likely included people fasting for reasons such as poverty, stress, depression, or nicotine and drug use, which he says cannot be reliably separated from people doing time-restricted eating.
• The speaker criticizes the American Heart Association for issuing a press release on unvetted research and questions its motive, which he says led mainstream outlets to report it widely.

Details Worth Noting

• Concrete instructions: The video gives no step-by-step fasting protocol. Its only actionable advice is to ask the American Heart Association, on Twitter/X, YouTube, or elsewhere, why it issued the press release on this poster presentation, and to hold off on trusting or republishing future association press releases until the research is vetted.
• The speaker says the study covered two food frequency questionnaires administered across the NHANES dataset, a method he describes as notoriously unreliable.
• Dr. Berry says that in other research disciplines, including veterinary and porcine nutrition, a hazard ratio under 2 is generally considered background noise and would not usually be published.
• He cites anthropological evidence that humans fasted for days historically, and that long fasts were a routine part of major religious traditions for adults who were not pregnant or breastfeeding.
• He says mainstream outlets are not at fault for relying on the press release, noting many no longer employ science editors to vet such claims.

Bottom Line

The speaker argues the headline fasting risk is based on a preliminary, unvetted observational analysis that he considers unreliable, so viewers should treat it cautiously rather than as an established health warning.