Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • News & Views
  • Published:


Safety and efficacy of alternate day fasting

Alternate day fasting (ADF) has gained considerable popularity as a weight loss intervention. A new study provides data showing that zero-calorie ADF (defined as 36-hour water fast alternating with 12-hour feast) is a safe and effective intervention to lower body weight and metabolic disease risk in participants who did not have obesity.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout


  1. Hoddy, K. K. et al. Meal timing during alternate day fasting: impact on body weight and cardiovascular disease risk in obese adults. Obesity 22, 2524–2531 (2014).

    Article  CAS  Google Scholar 

  2. Patterson, R. E. & Sears, D. D. Metabolic effects of intermittent fasting. Annu. Rev. Nutr. 37, 371–393 (2017).

    Article  CAS  Google Scholar 

  3. Trepanowski, J. F. et al. Effect of alternate-day fasting on weight loss, weight maintenance, and cardioprotection among metabolically healthy obese adults: a randomized clinical trial. JAMA Intern. Med. 177, 930–938 (2017).

    Article  Google Scholar 

  4. Gabel, K. et al. Differential effects of alternate-day fasting versus daily calorie restriction on insulin resistance. Obesity 27, 1443–1450 (2019).

    CAS  PubMed  Google Scholar 

  5. Stekovic, S. et al. Alternate day fasting improves physiological and molecular markers of aging in healthy, non-obese humans. Cell Metab. 30, 462–476 (2019).

    Article  CAS  Google Scholar 

  6. Barnosky, A. et al. Effect of alternate day fasting on markers of bone metabolism: an exploratory analysis of a 6-month randomized controlled trial. Nutr. Healthy Aging 4, 255–263 (2017).

    Article  CAS  Google Scholar 

  7. Hoddy, K. K. et al. Safety of alternate day fasting and effect on disordered eating behaviors. Nutr. J. 14, 44 (2015).

    Article  Google Scholar 

  8. Catenacci, V. A. et al. A randomized pilot study comparing zero-calorie alternate-day fasting to daily caloric restriction in adults with obesity. Obesity 24, 1874–1883 (2016).

    Article  CAS  Google Scholar 

  9. Heilbronn, L. K. et al. Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism. Am. J. Clin. Nutr. 81, 69–73 (2005).

    Article  CAS  Google Scholar 

  10. Cioffi, I. et al. Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials. J. Transl Med. 16, 371 (2018).

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Krista A. Varady.

Ethics declarations

Competing interests

K.A.V. received author fees from Hachette Book Group for the book The Every Other Day Diet. K.G. declares no competing interests.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Varady, K.A., Gabel, K. Safety and efficacy of alternate day fasting. Nat Rev Endocrinol 15, 686–687 (2019).

Download citation

  • Published:

  • Issue Date:

  • DOI:


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing