Fasting Diets

  • Medical Author:
    Erica Oberg, ND, MPH

    Dr. Erica Oberg, ND, MPH, received a BA in anthropology from the University of Colorado, her doctorate of naturopathic medicine (ND) from Bastyr University, and a masters of public health (MPH) in health services research from the University of Washington. She completed her residency at the Bastyr Center for Natural Health in ambulatory primary care and fellowship training at the Health Promotion Research Center at the University of Washington.

  • Medical Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Quick GuideDiet and Weight Loss: Healthy Dieting Myths and Facts

Diet and Weight Loss: Healthy Dieting Myths and Facts

What are the health risks of fasting diets?

Although more research is needed to fully understand the long-term benefits and risks of fasting diets, the short-term risks to consider include headaches, irritability, and fatigue. Electrolytes can be disrupted by fasting and can be monitored with blood tests.

Anyone considering a fasting or detox diet should first consult with a health-care professional, and certain people should never try one of these diets. People who are on medications for blood pressure or diabetes may have to reduce their medications while fasting; in addition, some diabetics may have dangerous high and/or lows in glucose levels if they attempt certain diets. They should be monitored and work in partnership with a health-care provider (for example, their primary-care provider and/or specialist). Also, fasting or any other type of diet that severely restricts calories is not recommended for pregnant or women who are breastfeeding.


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Goldhamer, A.C., et al. "Water-only fasting and an exclusively plant foods diet in the management of stage IIIa, low-grade follicular lymphoma." BMJ Case Rep Dec. 10, 2015.

Heilbronn, L.K., et al. "Effect of 6-month calorie restriction on biomarkers of longevity, metabolic adaptation, and oxidative stress in overweight individuals: a randomized controlled trial." JAMA 295.13 Apr. 5, 2006: 1539-1548.

Horne, B.D., J.B. Muhlestein, and J.L. Anderson. "Health effects of intermittent fasting: hormesis or harm? A systematic review." Am J Clin Nutr 102.2 Aug. 2015: 464-470.

Longo, V.D., and M.P. Mattson. "Fasting: molecular mechanisms and clinical applications." Cell Metab 19.2 Feb. 4, 2014: 181-192.

Medically Reviewed by a Doctor on 5/6/2016

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  • Fasting Diets - Experience

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  • Fasting Diets - Benefits

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