Monday, Aug 31, 2026 The claims desk. Receipts included. POWERED BY LENZ
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Intermittent fasting is generally safe for most studied adults.

The Claim

Intermittent fasting is harmful to human health.

The Short Version

Current evidence does not support characterizing intermittent fasting as generally harmful. Clinical reviews and trial meta-analyses find no overall increase in adverse events and report some weight and cardiometabolic benefits. Risks remain for people who are pregnant, have eating disorders, take certain diabetes medications, or follow fasting regimens without appropriate supervision; long-term evidence is also less certain.

Caveats

  • Safety evidence is strongest for studied adult populations, often those with overweight or obesity; long-term outcomes remain less certain.
  • Fasting may be inappropriate during pregnancy or for people with eating disorders and can require medical supervision when diabetes medications are used.
  • Reported cardiovascular mortality associations are not established as causal and should not outweigh synthesized clinical-trial evidence.

The Receipts

  1. Clinical application of intermittent fasting for weight loss: progress and future directions | Nature Reviews Endocrinology

    nature.com

  2. Intermittent fasting strategies and their effects on body ...

    bmj.com

  3. Intermittent Fasting and Obesity-Related Health Outcomes

    jamanetwork.com

  4. Intermittent fasting to treat diabetes: time to update clinical practice guidelines - The Lancet Diabetes & Endocrinology

    thelancet.com

  5. Adverse events profile associated with intermittent fasting in ...

    pmc.ncbi.nlm.nih.gov

  6. Intermittent fasting and health outcomes: an umbrella review of systematic reviews and meta-analyses of randomised controlled trials

    doi.org

  7. Intermittent fasting improves metabolic outcomes in metabolic syndrome: a systematic review and meta-analysis with GRADE evaluation - PMC

    pmc.ncbi.nlm.nih.gov

  8. The effect of intermittent fasting on insulin resistance, lipid profile, and inflammation on metabolic syndrome: a GRADE assessed systematic review and meta-analysis | Journal of Health, Population and Nutrition | Springer Nature Link

    link.springer.com

  9. Overweight | Adverse events profile associated with intermittent fasting in adults with overweight or obesity: a systematic review and meta-analysis of randomized controlled trials | springermedicine.com

    springermedicine.com

  10. Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: systematic review and network meta-analysis of randomised clinical trials

    doi.org

+ 23 more sources — see the full list on Lenz

Filed Under

Intermittent Fasting

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